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Low-temperature X-ray diffraction experiments were em­ployed to investigate the crystal structures of an ortho­rhom­bic polymorph of the intra­molecular cyclization product of perindopril, a popular angiotensive-converting enzyme (ACE) inhibitor, namely ethyl (2S)-2-[(3S,5aS,9aS,10aS)-3-methyl-1,4-dioxo-5a,6,7,8,9,9a,10,10a-octa­hydro-3H-pyrazino­[1,2-a]indol-2-yl]penta­noate, C19H30N2O4, (Io), and its tetra­gonal equivalent, (It), which was previously reported at ambient temperature [Bojarska et al. (2013). J. Chil. Chem. Soc. 58, 1415-1417]. Polymorph (Io) crystallizes in the ortho­rhom­bic space group P212121 with two mol­ecules in the asymmetric unit, while tetra­gonal form (It) crystallizes in the space group P41212 with one mol­ecule in the asymmetric unit. The geometric parameters of (Io) are very similar to those of (It). The six-membered rings in both polymorphs adopt a slightly deformed chair conformation and the piperazinedione rings are in a boat conformation. However, the proline rings adopt an envelope conformation in (Io), while in (It) the ring exists in a slightly deformed half-chair conformation. The most significant difference between the two structures is the orientation of the ethyl penta­noate chain. Mol­ecules associate in pairs in a head-to-tail manner forming infinite columns. In (Io), mol­ecules are related by a twofold screw axis forming identical columns, while in (It), mol­ecules in successive neighbouring columns are related by alternating twofold screw axes and fourfold screw axes. In both cases, the crystal packing is stabilized by weak inter­molecular C-H...O inter­actions only.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270113011025/tp3019sup1.cif
Contains datablocks global, Io, It

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270113011025/tp3019Iosup2.hkl
Contains datablock Io

cml

Chemical Markup Language (CML) file https://doi.org/10.1107/S0108270113011025/tp3019Iosup4.cml
Supplementary material

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270113011025/tp3019Itsup3.hkl
Contains datablock It

cml

Chemical Markup Language (CML) file https://doi.org/10.1107/S0108270113011025/tp3019Itsup5.cml
Supplementary material

CCDC references: 950437; 950438

Comment top

Perindopril has particularly valuable pharmacological properties because it belongs to a group of angiotensive-converting enzyme (ACE) inhibitors, which show biological activity in the treatment of high blood pressure and heart failure (Ferrari, 2005, 2008). In view of the medicinal value of this compound, it has been of prime importance to synthesize it with very high purity. Nevertheless, perindopril, similarly to other dipeptide drugs, is liable to degradation inter alia via isomerization at some chiral centres, hydrolysis of the side-chain ester group or cyclization (Harn & Furlan, 2010). Diketopiperazine derivatives (DKP) are degradation products of perindopril, from its intramolecular cyclization (Medenica et al., 2007). The DKP formation mechanism was decribed by Gomes et al. (2007). It is worth mentioning that DKP forming is principally a stability problem not only for perindopril but also for other ACE inhibitors such as enalapril, moexipril, lisinopril, ramipril and quinapril. Despite the fact that perindopril has been known since the early 1980s (Vincent et al., 1982), this compound has not been well structurally characterized. We published recently the first crystal structures of perindopril erbumine (Remko et al., 2011). Currently, we are focusing our attention on the perindopril cyclization products, which resulted in the publication of the first polymorph of DKP-perindopril {systematic name: ethyl (2S)-2-[(3S,5aS,9aS,10aS)-3-methyl-1,4-dioxo-5a,6,7,8,9,9a,10,10a-octahydro-3H-pyrazino[1,2-a]indol-2-yl]pentanoate}, crystallized from a nitrobenzene solution. The room-temperature structure proved to be tetragonal, with the P41212 space group (It') (Bojarska et al., 2013).

Herein we report an orthorhombic polymorph, (Io), of (It'), which was recrystallizated from an acetic acid/water solution. To compare the two polymorphs, a redetermination of the crystal structure of the tetragonal polymorph form (It) was carried out at 100 K. As expected, the unit-cell dimensions and atomic coordinates show that the phase is the same at low temperature as at ambient temperature. Likewise, the geometric parameters of the redetermined structure agree well with those previously reported, but with improved precision. The low-temperature structure (It) refined to R = 0.0391 for 3352 data with I > 2σ(I) and R = 0.0391 for all 3356 data, while the structure determined previously at room temperature, (It'), refined to R = 0.0485 for 3549 data with I > 2σ(I) and R = 0.0494 for all 3644 data. It is worth mentioning that at both temperatures the terminal groups of the alkyl chain are disordered and exist in two equally occupied conformations. The Flack parameter at 100 K is 0.1 (3) (Flack, 1983). Thus, the standard uncertainty value is greater than 0.1 (regarded as the upper limit for a compound recognized as enantiopure) (Flack & Bernardinelli, 2000). On the other hand, Bayesian analysis of the Bijvoet-pair intensity differences carried out within PLATON (Spek, 2009) made it possible to calculate the Hooft parameter of 0.12 (7) (Hooft et al., 2008), suggesting that the absolute configuration is correctly established.

We reveal that (Io) crystallizes in the noncentrosymmetric space group P212121. The crystal structure is comprises two crystallographically independent molecules in the asymmetric unit (Fig. 1), while (It) structure contains one molecule per assymetric unit. There is a good geometrical agreement between the two analyzed polymorphs. The C—C, C—O and C—N bond lengths found in (Io) are very similar to those found in (It). As for (It), both molecules of (Io) (labelled with the suffixes A and B) have the same S configuration at all five chiral C atoms.

In (Io), the conformations of molecules A and B are similar, favouring a slightly deformed chair for both six-membered rings (C3–C8), an envelope conformation for the proline rings (N1/C1–C3/C8) and a boat conformation for the diketopiperazine rings (N1/C1–C15/N2/C9–C10). The ring-puckering parameters (Cremer & Pople, 1975; Spek, 2009) are provided in the Supplementary materials. The diketopiperazine ring conformation defines the position of the O atoms of the carbonyl groups (O1 and O4), which lie on the same side of the pyrrolidine ring in both molecules of (Io). This is the same for (It). For (Io), the conformation of the ethyl pentanoate chain is either antiperiplanar or synclinal, with C17—O3—C18—C19 having torsion angles of 175.7 (5) and 79.2 (4)° for molecules A and B, respectively. In (It), the disordered ethyl pentanoate chain is oriented in an anticlinal or in an antiperiplanar conformation, as indicated by the dihedral [torsion?] angle values of 97.5 (4) and 156.4 (5)°, respectively. We also observed a subtle distinction between the two polymorphs in the conformation of the proline rings. As mentioned previously, the proline rings adopt an envelope conformation for (Io), while in (It) the proline ring exists in a slightly deformed half-chair conformation. Overlaying both structures (Fig. 2) demonstrates that they are conformational polymorphs.

Some similarities between the packing of (Io) and (It) are observed (Figs. 3 and 4). In both polymorphs, the DKP–perindopril molecules pack in separate columns extending through the crystal. However, in (Io), molecules are arranged in a head-to-tail motif in pairs around a crystallographic twofold screw axis in identical columns, while in (It) molecules are arranged in two different types of columns which alternate. Molecules in the first type of column are packed in the same manner as in ((Io), while molecules in the second type are related by the fourfold screw axes, maintaing the same head-to-tail motif.

Both (It) and (Io) are stabilized only by intermolecular C—H···O interactions (Table 1 and 2). However, it is well known that such weak interactions can play an important role in drug action and polymorphism (Umezawa & Nishio, 2005; Desiraju, 1997, 2005; Braga et al., 2009). In the case of (Io), four such contacts exist within the accepted range for C—H···O hydrogen bonds (Desiraju, 1996; Table 1). The C19B–H19E···O1Biii interaction links the molecules into an infinite 10-membered chain along the a axis with the C(10) graph-set motif [symmetry code: (iii) x-1, y, z]. A similar contact, C10A–H10A···O4B, participates in the formation of two additional chains, viz. C22(11) along the b axis with C11A–H11A···O2Bii and C22(10) along the a axis with C10B–H10B···O4Ai (Etter et al., 1990; Bernstein et al., (1995) [symmetry codes: (i) x+1, y, z; (ii) -x+1, y+1/2, -z+3/2]. These chains together result in the graph-set descriptor R33(18). Furthermore, edge-fused rings with the R55(28) motif are also present (Fig. 5).

In conclusion, (It) and (Io) can be classified as conformational polymorphs displaying significant similarities but also differences, particularly in the packing motifs.

Related literature top

For related literature, see: Bernstein et al. (1995); Braga et al. (2009); Cremer & Pople (1975); Desiraju (1996, 1997, 2005); Etter et al. (1990); Ferrari (2005, 2008); Flack (1983); Flack & Bernardinelli (2000); Gomes et al. (2007); Harn & Furlan (2010); Hooft et al. (2008); Medenica et al. (2007); Remko et al. (2011); Spek (2009); Umezawa & Nishio (2005); Vincent et al. (1982).

Experimental top

Perindopril has been obtained in accordance with the procedure described by Vincent (Vincent et al., 1982). During recrystallization, colourless needle-shaped crystals of (Io) and plate-shaped crystals of the tetragonal form (It) were grown from solutions in acetic acid and water (1:1 v/v) and methylene chloride, respectively, by slow evaporation at room temperature over a period of several weeks.

Refinement top

All H atoms were visible in difference Fourier maps and subsequently positioned geometrically and refined using a riding model, with fixed C—H distances (0.97–1.00 Å) and with Uiso(H) = 1.5Ueq(C) for methyl H atoms or 1.2Ueq(C) otherwise. In the case of (It), the terminal ethyl group (C18—C19) of the n-alkyl chain was treated as disordered over two equal sets of positions using DFIX restraints for the C—C and C—O distances of 1.525 and 1.400 Å, respectively.

Computing details top

For both compounds, data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-Plus (Bruker, 2008); data reduction: SAINT-Plus (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009) and Mercury (Macrae et al., 2008); software used to prepare material for publication: PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, (Io), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. The molecular structure of polymorph (It), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 3] Fig. 3. A superimposition of the structures showing the conformational differences between molecules A and B of (Io) (Mercury; Macrae et al., 2008). The overlay was carried out using a least-squares fit of the common amide plane; the A and B molecules of (Io) are shown in blue and green, respectively, and the two conformers of tetragonal polymorph (It) in medium grey and black. H atoms have been omitted for clarity.
[Figure 4] Fig. 4. The crystal packing of (Io), showing the columnar arrangement of the molecules along the a axis. All H atoms have been omitted for clarity.
[Figure 5] Fig. 5. The crystal packing of (It), projected down the b axis. All H atoms have been omitted for clarity.
[Figure 6] Fig. 6. The intermolecular hydrogen bonding in (Io) determining the packing of molecules in the crystal. H atoms not involved in the hydrogen bonds have been omitted for clarity. [Symmetry codes: (i) x+1, y, z; (ii) -x+1, y+1/2, -z+3/2; (iii) x-1, y, z].
(Io) Ethyl (2S)-2-[(3S,5aS,9aS,10aS)-3-methyl-1,4-dioxo-5a,6,7,8,9,9a,10,10a-octahydro-3H-pyrazino[1,2-a]indol-2-yl]pentanoate top
Crystal data top
C19H30N2O4F(000) = 1520
Mr = 350.45Dx = 1.186 Mg m3
Orthorhombic, P212121Cu Kα radiation, λ = 1.54178 Å
Hall symbol: P 2ac 2abCell parameters from 9895 reflections
a = 9.2089 (10) Åθ = 3.1–73.7°
b = 17.9875 (17) ŵ = 0.67 mm1
c = 23.697 (2) ÅT = 100 K
V = 3925.3 (7) Å3Needle, colourless
Z = 80.50 × 0.15 × 0.10 mm
Data collection top
Bruker APEXII CCD
diffractometer
6791 independent reflections
Radiation source: 30W microsource with MonoCap capillary5706 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.043
ω scanθmax = 66.0°, θmin = 3.1°
Absorption correction: multi-scan
SADABS (Sheldrick, 2003)
h = 109
Tmin = 0.886, Tmax = 0.935k = 2121
39028 measured reflectionsl = 2828
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.057 w = 1/[σ2(Fo2) + (0.04P)2 + 4.25P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.145(Δ/σ)max < 0.001
S = 1.12Δρmax = 0.46 e Å3
6791 reflectionsΔρmin = 0.37 e Å3
458 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), FC*=KFC[1+0.001XFC2Λ3/SIN(2Θ)]-1/4
0 restraintsExtinction coefficient: 0.00149 (10)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983), 2958 Friedel pairs
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 0.1 (3)
Crystal data top
C19H30N2O4V = 3925.3 (7) Å3
Mr = 350.45Z = 8
Orthorhombic, P212121Cu Kα radiation
a = 9.2089 (10) ŵ = 0.67 mm1
b = 17.9875 (17) ÅT = 100 K
c = 23.697 (2) Å0.50 × 0.15 × 0.10 mm
Data collection top
Bruker APEXII CCD
diffractometer
6791 independent reflections
Absorption correction: multi-scan
SADABS (Sheldrick, 2003)
5706 reflections with I > 2σ(I)
Tmin = 0.886, Tmax = 0.935Rint = 0.043
39028 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.057H-atom parameters constrained
wR(F2) = 0.145Δρmax = 0.46 e Å3
S = 1.12Δρmin = 0.37 e Å3
6791 reflectionsAbsolute structure: Flack (1983), 2958 Friedel pairs
458 parametersAbsolute structure parameter: 0.1 (3)
0 restraints
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating -R-factor-obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O1A0.7338 (3)0.41481 (16)0.87882 (11)0.0527 (10)
O2A0.1003 (3)0.50744 (16)0.76821 (13)0.0607 (11)
O3A0.2297 (3)0.47699 (14)0.84504 (11)0.0463 (9)
O4A0.2614 (3)0.34392 (13)0.77119 (10)0.0395 (8)
N1A0.5933 (3)0.32183 (14)0.84485 (11)0.0334 (9)
N2A0.4493 (3)0.42472 (14)0.78054 (12)0.0328 (9)
C1A0.4916 (4)0.29456 (17)0.80141 (13)0.0325 (10)
C2A0.4151 (4)0.22878 (18)0.82979 (13)0.0353 (10)
C3A0.5239 (4)0.20366 (19)0.87538 (15)0.0377 (11)
C4A0.4633 (5)0.1542 (2)0.92239 (16)0.0463 (14)
C5A0.3683 (5)0.1957 (2)0.96486 (15)0.0448 (13)
C6A0.4480 (5)0.2628 (3)0.98799 (16)0.0563 (16)
C7A0.4896 (5)0.3151 (2)0.94022 (15)0.0469 (14)
C8A0.5877 (4)0.27718 (19)0.89694 (14)0.0393 (11)
C9A0.6520 (4)0.39003 (19)0.84227 (15)0.0380 (11)
C10A0.6091 (4)0.43329 (18)0.78956 (15)0.0366 (11)
C11A0.3586 (4)0.48495 (19)0.75859 (15)0.0406 (11)
C12A0.3245 (5)0.4775 (2)0.69494 (17)0.0567 (16)
C13A0.4523 (5)0.4716 (3)0.65728 (19)0.0637 (17)
C14A0.4069 (5)0.4600 (3)0.59610 (16)0.0540 (16)
C15A0.3904 (4)0.35630 (18)0.78305 (13)0.0343 (10)
C16A0.6593 (5)0.5132 (2)0.79400 (19)0.0516 (15)
C17A0.2153 (5)0.48902 (19)0.79004 (17)0.0440 (13)
C18A0.0964 (6)0.4800 (3)0.8786 (2)0.078 (2)
C19A0.1357 (8)0.4593 (5)0.9376 (2)0.127 (4)
O1B1.1714 (3)0.26860 (15)0.56453 (10)0.0436 (8)
O2B0.6227 (3)0.15899 (13)0.69843 (11)0.0432 (8)
O3B0.7491 (3)0.19440 (14)0.62110 (9)0.0413 (8)
O4B0.7550 (3)0.32544 (12)0.69933 (9)0.0343 (7)
N1B1.0488 (3)0.36023 (15)0.61012 (11)0.0339 (9)
N2B0.9550 (3)0.25450 (13)0.68466 (11)0.0277 (8)
C1B0.9700 (4)0.38430 (17)0.66130 (13)0.0318 (10)
C2B0.8816 (5)0.45143 (18)0.64114 (15)0.0398 (11)
C3B0.9712 (4)0.48045 (19)0.59099 (16)0.0404 (11)
C4B0.8977 (5)0.5355 (2)0.55098 (18)0.0520 (14)
C5B0.7866 (5)0.5011 (2)0.51198 (17)0.0533 (16)
C6B0.8478 (5)0.4337 (3)0.48134 (17)0.0567 (16)
C7B0.9001 (4)0.3758 (2)0.52393 (14)0.0438 (11)
C8B1.0181 (4)0.40849 (19)0.56144 (14)0.0382 (11)
C9B1.1134 (4)0.29335 (18)0.60717 (14)0.0328 (10)
C10B1.1083 (4)0.25243 (17)0.66388 (14)0.0298 (10)
C11B0.8782 (4)0.18962 (17)0.70666 (13)0.0309 (10)
C12B0.8596 (4)0.1923 (2)0.77036 (13)0.0368 (11)
C13B1.0036 (4)0.1904 (3)0.80206 (15)0.0482 (13)
C14B0.9805 (5)0.2035 (3)0.86498 (16)0.0653 (18)
C15B0.8841 (4)0.31925 (17)0.68340 (12)0.0292 (10)
C16B1.1708 (4)0.17499 (19)0.65836 (17)0.0421 (11)
C17B0.7341 (4)0.18089 (18)0.67560 (14)0.0358 (10)
C18B0.6162 (4)0.1927 (2)0.58709 (16)0.0507 (14)
C19B0.5336 (5)0.2633 (2)0.59375 (19)0.0557 (16)
H1A0.547800.276300.768100.0390*
H2A0.321900.244400.846900.0420*
H2B0.396200.188400.802400.0420*
H3A0.603600.175600.856200.0450*
H4A0.545500.131000.942800.0550*
H4B0.405400.113800.905100.0550*
H5A0.342200.161900.996200.0540*
H5B0.277500.212000.946200.0540*
H6A0.536600.246301.008100.0680*
H6B0.385100.289201.015300.0680*
H7A0.400400.332900.921200.0560*
H7B0.540500.358900.956000.0560*
H8A0.687300.269400.912600.0470*
H10A0.659900.410200.756600.0440*
H11A0.411400.532900.764600.0490*
H12A0.266700.521300.683200.0680*
H12B0.263200.432900.689400.0680*
H13A0.511000.517500.660200.0760*
H13B0.513600.429300.669600.0760*
H14A0.346300.501800.583800.0810*
H14B0.351600.413600.592900.0810*
H14C0.493600.457100.572200.0810*
H16A0.643600.538400.757800.0770*
H16B0.603900.538600.823600.0770*
H16C0.762900.514400.803400.0770*
H18A0.023600.444800.863300.0930*
H18B0.054800.530700.877600.0930*
H19A0.164000.406800.938800.1910*
H19B0.216900.490100.950400.1910*
H19C0.051800.467200.962300.1910*
H1B1.041400.400700.690600.0380*
H2C0.873400.489500.671100.0480*
H2D0.783000.436400.629100.0480*
H3B1.060300.504800.606400.0490*
H4C0.973400.559900.527800.0620*
H4D0.849600.574500.573700.0620*
H5C0.700400.485900.534200.0640*
H5D0.755100.538500.483900.0640*
H6C0.771900.411600.457000.0680*
H6D0.929800.449100.457000.0680*
H7C0.938800.331900.503600.0530*
H7D0.817500.359300.547500.0530*
H8B1.108700.417100.539100.0460*
H10B1.169800.280700.691300.0360*
H11B0.938500.144900.697700.0370*
H12C0.806900.238300.780600.0440*
H12D0.799600.149500.782400.0440*
H13C1.050600.141400.796300.0580*
H13D1.069100.229100.786800.0580*
H14D0.938100.252900.870800.0980*
H14E0.914600.165600.880000.0980*
H14F1.074000.200500.884600.0980*
H16D1.170100.150600.695300.0630*
H16E1.111900.146100.631800.0630*
H16F1.270800.178100.644400.0630*
H18C0.641700.185500.546900.0610*
H18D0.554900.150300.599100.0610*
H19D0.594400.305200.581900.0840*
H19E0.446000.261500.570300.0840*
H19F0.505900.269600.633400.0840*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O1A0.0523 (18)0.0608 (18)0.0451 (15)0.0187 (14)0.0020 (14)0.0108 (13)
O2A0.059 (2)0.0472 (16)0.076 (2)0.0077 (15)0.0148 (17)0.0109 (15)
O3A0.0462 (16)0.0469 (15)0.0458 (15)0.0085 (13)0.0123 (13)0.0016 (12)
O4A0.0427 (15)0.0331 (12)0.0428 (13)0.0025 (11)0.0072 (12)0.0039 (10)
N1A0.0382 (17)0.0303 (14)0.0316 (14)0.0032 (13)0.0050 (13)0.0032 (12)
N2A0.0359 (17)0.0239 (13)0.0386 (15)0.0023 (12)0.0026 (13)0.0024 (11)
C1A0.046 (2)0.0235 (16)0.0279 (16)0.0017 (14)0.0041 (15)0.0044 (13)
C2A0.050 (2)0.0269 (16)0.0289 (17)0.0063 (16)0.0025 (16)0.0047 (13)
C3A0.044 (2)0.0314 (18)0.0378 (18)0.0066 (16)0.0026 (17)0.0004 (15)
C4A0.058 (3)0.0388 (19)0.042 (2)0.0036 (19)0.0044 (19)0.0071 (16)
C5A0.057 (3)0.045 (2)0.0325 (18)0.0048 (19)0.0004 (18)0.0005 (16)
C6A0.069 (3)0.068 (3)0.032 (2)0.020 (2)0.0030 (19)0.0098 (19)
C7A0.057 (3)0.046 (2)0.0378 (19)0.015 (2)0.0030 (18)0.0166 (17)
C8A0.045 (2)0.0404 (19)0.0326 (18)0.0017 (17)0.0034 (16)0.0000 (15)
C9A0.042 (2)0.0371 (19)0.0349 (18)0.0040 (16)0.0037 (17)0.0105 (16)
C10A0.039 (2)0.0287 (17)0.0420 (19)0.0094 (15)0.0023 (16)0.0081 (15)
C11A0.053 (2)0.0259 (17)0.043 (2)0.0091 (17)0.0085 (18)0.0012 (15)
C12A0.070 (3)0.054 (3)0.046 (2)0.016 (2)0.010 (2)0.009 (2)
C13A0.062 (3)0.076 (3)0.053 (3)0.004 (3)0.007 (2)0.010 (2)
C14A0.050 (3)0.071 (3)0.041 (2)0.004 (2)0.0072 (19)0.003 (2)
C15A0.047 (2)0.0265 (16)0.0295 (16)0.0034 (15)0.0013 (16)0.0049 (13)
C16A0.059 (3)0.0299 (19)0.066 (3)0.0144 (18)0.012 (2)0.0126 (18)
C17A0.053 (3)0.0261 (18)0.053 (2)0.0019 (17)0.0037 (19)0.0026 (16)
C18A0.061 (3)0.083 (4)0.089 (4)0.027 (3)0.043 (3)0.030 (3)
C19A0.108 (6)0.195 (8)0.079 (4)0.062 (5)0.053 (4)0.050 (5)
O1B0.0447 (16)0.0525 (15)0.0337 (13)0.0121 (13)0.0097 (12)0.0026 (12)
O2B0.0450 (16)0.0354 (13)0.0492 (14)0.0069 (12)0.0032 (13)0.0050 (11)
O3B0.0421 (15)0.0497 (15)0.0321 (12)0.0026 (12)0.0066 (11)0.0071 (11)
O4B0.0401 (14)0.0319 (12)0.0310 (11)0.0022 (10)0.0071 (11)0.0016 (9)
N1B0.0413 (18)0.0313 (15)0.0290 (14)0.0007 (13)0.0085 (13)0.0075 (11)
N2B0.0324 (15)0.0223 (13)0.0285 (14)0.0042 (11)0.0056 (12)0.0001 (10)
C1B0.043 (2)0.0241 (15)0.0283 (16)0.0019 (15)0.0042 (15)0.0023 (13)
C2B0.050 (2)0.0254 (17)0.044 (2)0.0035 (16)0.0051 (18)0.0043 (14)
C3B0.042 (2)0.0313 (18)0.048 (2)0.0012 (16)0.0024 (17)0.0133 (16)
C4B0.054 (3)0.044 (2)0.058 (2)0.010 (2)0.007 (2)0.0239 (19)
C5B0.052 (3)0.061 (3)0.047 (2)0.018 (2)0.0051 (19)0.018 (2)
C6B0.056 (3)0.077 (3)0.037 (2)0.022 (2)0.0001 (19)0.009 (2)
C7B0.048 (2)0.054 (2)0.0293 (17)0.0089 (19)0.0064 (17)0.0008 (16)
C8B0.041 (2)0.0408 (19)0.0327 (18)0.0049 (17)0.0069 (16)0.0140 (15)
C9B0.0346 (19)0.0324 (17)0.0315 (17)0.0009 (15)0.0018 (15)0.0014 (14)
C10B0.0265 (17)0.0298 (16)0.0330 (17)0.0033 (14)0.0072 (14)0.0017 (13)
C11B0.0344 (19)0.0251 (15)0.0331 (17)0.0041 (14)0.0005 (15)0.0035 (13)
C12B0.041 (2)0.0389 (19)0.0304 (17)0.0031 (16)0.0019 (15)0.0045 (14)
C13B0.045 (2)0.068 (3)0.0316 (18)0.005 (2)0.0035 (17)0.0093 (18)
C14B0.053 (3)0.109 (4)0.034 (2)0.005 (3)0.0064 (19)0.007 (2)
C15B0.040 (2)0.0277 (16)0.0199 (14)0.0016 (15)0.0057 (14)0.0029 (12)
C16B0.046 (2)0.0313 (18)0.049 (2)0.0109 (16)0.0092 (18)0.0037 (16)
C17B0.048 (2)0.0234 (16)0.0360 (18)0.0059 (16)0.0021 (17)0.0018 (13)
C18B0.042 (2)0.069 (3)0.041 (2)0.006 (2)0.0149 (18)0.0111 (19)
C19B0.047 (3)0.065 (3)0.055 (2)0.001 (2)0.013 (2)0.002 (2)
Geometric parameters (Å, º) top
O1A—C9A1.231 (4)C14A—H14A0.9800
O2A—C17A1.224 (5)C14A—H14B0.9800
O3A—C17A1.328 (5)C14A—H14C0.9800
O3A—C18A1.464 (6)C16A—H16C0.9800
O4A—C15A1.241 (5)C16A—H16A0.9800
O1B—C9B1.227 (4)C16A—H16B0.9800
O2B—C17B1.225 (4)C18A—H18B0.9900
O3B—C17B1.321 (4)C18A—H18A0.9900
O3B—C18B1.466 (5)C19A—H19B0.9800
O4B—C15B1.252 (5)C19A—H19C0.9800
N1A—C1A1.476 (4)C19A—H19A0.9800
N1A—C8A1.474 (4)C1B—C2B1.533 (5)
N1A—C9A1.342 (4)C1B—C15B1.506 (5)
N2A—C11A1.464 (4)C2B—C3B1.538 (5)
N2A—C15A1.346 (4)C3B—C4B1.529 (5)
N2A—C10A1.495 (5)C3B—C8B1.534 (5)
N1B—C1B1.478 (4)C4B—C5B1.511 (6)
N1B—C8B1.471 (4)C5B—C6B1.521 (6)
N1B—C9B1.344 (4)C6B—C7B1.528 (6)
N2B—C10B1.496 (5)C7B—C8B1.522 (5)
N2B—C11B1.461 (4)C9B—C10B1.533 (5)
N2B—C15B1.336 (4)C10B—C16B1.513 (5)
C1A—C2A1.533 (5)C11B—C12B1.520 (4)
C1A—C15A1.514 (5)C11B—C17B1.526 (5)
C2A—C3A1.541 (5)C12B—C13B1.525 (5)
C3A—C4A1.531 (5)C13B—C14B1.524 (5)
C3A—C8A1.535 (5)C18B—C19B1.489 (5)
C4A—C5A1.528 (6)C1B—H1B1.0000
C5A—C6A1.515 (6)C2B—H2C0.9900
C6A—C7A1.521 (6)C2B—H2D0.9900
C7A—C8A1.528 (5)C3B—H3B1.0000
C9A—C10A1.524 (5)C4B—H4C0.9900
C10A—C16A1.514 (5)C4B—H4D0.9900
C11A—C17A1.517 (6)C5B—H5C0.9900
C11A—C12A1.547 (5)C5B—H5D0.9900
C12A—C13A1.481 (6)C6B—H6C0.9900
C13A—C14A1.523 (6)C6B—H6D0.9900
C18A—C19A1.491 (7)C7B—H7C0.9900
C1A—H1A1.0000C7B—H7D0.9900
C2A—H2B0.9900C8B—H8B1.0000
C2A—H2A0.9900C10B—H10B1.0000
C3A—H3A1.0000C11B—H11B1.0000
C4A—H4B0.9900C12B—H12C0.9900
C4A—H4A0.9900C12B—H12D0.9900
C5A—H5B0.9900C13B—H13C0.9900
C5A—H5A0.9900C13B—H13D0.9900
C6A—H6A0.9900C14B—H14D0.9800
C6A—H6B0.9900C14B—H14E0.9800
C7A—H7B0.9900C14B—H14F0.9800
C7A—H7A0.9900C16B—H16D0.9800
C8A—H8A1.0000C16B—H16E0.9800
C10A—H10A1.0000C16B—H16F0.9800
C11A—H11A1.0000C18B—H18C0.9900
C12A—H12A0.9900C18B—H18D0.9900
C12A—H12B0.9900C19B—H19D0.9800
C13A—H13B0.9900C19B—H19E0.9800
C13A—H13A0.9900C19B—H19F0.9800
C17A—O3A—C18A116.3 (3)H18A—C18A—H18B109.00
C17B—O3B—C18B116.5 (3)C18A—C19A—H19A109.00
C1A—N1A—C8A112.4 (2)C18A—C19A—H19B110.00
C1A—N1A—C9A121.9 (3)C18A—C19A—H19C109.00
C8A—N1A—C9A123.4 (3)H19A—C19A—H19B109.00
C10A—N2A—C15A119.0 (3)H19A—C19A—H19C109.00
C11A—N2A—C15A117.6 (3)H19B—C19A—H19C110.00
C10A—N2A—C11A122.4 (3)N1B—C1B—C2B103.6 (3)
C8B—N1B—C9B124.9 (3)N1B—C1B—C15B108.4 (2)
C1B—N1B—C8B112.1 (3)C2B—C1B—C15B116.2 (3)
C1B—N1B—C9B121.5 (3)C1B—C2B—C3B102.9 (3)
C10B—N2B—C15B118.4 (3)C2B—C3B—C4B117.5 (3)
C11B—N2B—C15B117.9 (3)C2B—C3B—C8B102.6 (3)
C10B—N2B—C11B123.7 (2)C4B—C3B—C8B112.8 (3)
C2A—C1A—C15A114.2 (3)C3B—C4B—C5B114.4 (3)
N1A—C1A—C2A104.0 (2)C4B—C5B—C6B111.6 (4)
N1A—C1A—C15A110.3 (2)C5B—C6B—C7B110.2 (3)
C1A—C2A—C3A103.6 (3)C6B—C7B—C8B110.3 (3)
C2A—C3A—C4A116.3 (3)N1B—C8B—C3B101.2 (3)
C2A—C3A—C8A103.3 (3)N1B—C8B—C7B111.5 (3)
C4A—C3A—C8A113.5 (3)C3B—C8B—C7B113.1 (3)
C3A—C4A—C5A113.8 (3)O1B—C9B—N1B124.1 (3)
C4A—C5A—C6A110.5 (4)O1B—C9B—C10B124.1 (3)
C5A—C6A—C7A110.2 (3)N1B—C9B—C10B111.8 (3)
C6A—C7A—C8A111.9 (3)N2B—C10B—C9B107.8 (3)
N1A—C8A—C7A109.9 (3)N2B—C10B—C16B114.2 (3)
C3A—C8A—C7A112.5 (3)C9B—C10B—C16B110.8 (3)
N1A—C8A—C3A101.8 (3)N2B—C11B—C12B112.6 (3)
N1A—C9A—C10A113.6 (3)N2B—C11B—C17B109.3 (3)
O1A—C9A—N1A123.0 (3)C12B—C11B—C17B112.6 (3)
O1A—C9A—C10A123.4 (3)C11B—C12B—C13B113.0 (3)
C9A—C10A—C16A110.4 (3)C12B—C13B—C14B110.9 (3)
N2A—C10A—C16A114.1 (3)O4B—C15B—N2B122.3 (3)
N2A—C10A—C9A108.7 (3)O4B—C15B—C1B122.3 (3)
N2A—C11A—C12A113.5 (3)N2B—C15B—C1B115.4 (3)
N2A—C11A—C17A111.0 (3)O2B—C17B—O3B125.3 (3)
C12A—C11A—C17A107.9 (3)O2B—C17B—C11B123.3 (3)
C11A—C12A—C13A115.6 (4)O3B—C17B—C11B111.2 (3)
C12A—C13A—C14A111.4 (4)O3B—C18B—C19B110.5 (3)
O4A—C15A—N2A122.7 (3)N1B—C1B—H1B109.00
O4A—C15A—C1A121.5 (3)C2B—C1B—H1B109.00
N2A—C15A—C1A115.8 (3)C15B—C1B—H1B109.00
O2A—C17A—C11A123.9 (4)C1B—C2B—H2C111.00
O2A—C17A—O3A123.0 (4)C1B—C2B—H2D111.00
O3A—C17A—C11A112.8 (4)C3B—C2B—H2C111.00
O3A—C18A—C19A107.3 (5)C3B—C2B—H2D111.00
C15A—C1A—H1A109.00H2C—C2B—H2D109.00
N1A—C1A—H1A109.00C2B—C3B—H3B108.00
C2A—C1A—H1A109.00C4B—C3B—H3B108.00
C1A—C2A—H2A111.00C8B—C3B—H3B108.00
C1A—C2A—H2B111.00C3B—C4B—H4C109.00
C3A—C2A—H2A111.00C3B—C4B—H4D109.00
C3A—C2A—H2B111.00C5B—C4B—H4C109.00
H2A—C2A—H2B109.00C5B—C4B—H4D109.00
C2A—C3A—H3A108.00H4C—C4B—H4D108.00
C4A—C3A—H3A108.00C4B—C5B—H5C109.00
C8A—C3A—H3A108.00C4B—C5B—H5D109.00
C3A—C4A—H4A109.00C6B—C5B—H5C109.00
C3A—C4A—H4B109.00C6B—C5B—H5D109.00
H4A—C4A—H4B108.00H5C—C5B—H5D108.00
C5A—C4A—H4B109.00C5B—C6B—H6C110.00
C5A—C4A—H4A109.00C5B—C6B—H6D110.00
C6A—C5A—H5B110.00C7B—C6B—H6C109.00
C6A—C5A—H5A110.00C7B—C6B—H6D110.00
C4A—C5A—H5B110.00H6C—C6B—H6D108.00
C4A—C5A—H5A109.00C6B—C7B—H7C110.00
H5A—C5A—H5B108.00C6B—C7B—H7D110.00
C5A—C6A—H6A110.00C8B—C7B—H7C110.00
C5A—C6A—H6B110.00C8B—C7B—H7D110.00
C7A—C6A—H6A110.00H7C—C7B—H7D108.00
C7A—C6A—H6B110.00N1B—C8B—H8B110.00
H6A—C6A—H6B108.00C3B—C8B—H8B110.00
C6A—C7A—H7A109.00C7B—C8B—H8B110.00
C8A—C7A—H7B109.00N2B—C10B—H10B108.00
C6A—C7A—H7B109.00C9B—C10B—H10B108.00
C8A—C7A—H7A109.00C16B—C10B—H10B108.00
H7A—C7A—H7B108.00N2B—C11B—H11B107.00
C7A—C8A—H8A111.00C12B—C11B—H11B107.00
N1A—C8A—H8A111.00C17B—C11B—H11B107.00
C3A—C8A—H8A111.00C11B—C12B—H12C109.00
N2A—C10A—H10A108.00C11B—C12B—H12D109.00
C9A—C10A—H10A108.00C13B—C12B—H12C109.00
C16A—C10A—H10A108.00C13B—C12B—H12D109.00
N2A—C11A—H11A108.00H12C—C12B—H12D108.00
C12A—C11A—H11A108.00C12B—C13B—H13C109.00
C17A—C11A—H11A108.00C12B—C13B—H13D110.00
C11A—C12A—H12A108.00C14B—C13B—H13C109.00
C11A—C12A—H12B108.00C14B—C13B—H13D109.00
C13A—C12A—H12B108.00H13C—C13B—H13D108.00
H12A—C12A—H12B108.00C13B—C14B—H14D109.00
C13A—C12A—H12A108.00C13B—C14B—H14E110.00
H13A—C13A—H13B108.00C13B—C14B—H14F109.00
C14A—C13A—H13B109.00H14D—C14B—H14E109.00
C12A—C13A—H13A109.00H14D—C14B—H14F109.00
C12A—C13A—H13B109.00H14E—C14B—H14F109.00
C14A—C13A—H13A109.00C10B—C16B—H16D109.00
C13A—C14A—H14A110.00C10B—C16B—H16E109.00
C13A—C14A—H14B109.00C10B—C16B—H16F110.00
C13A—C14A—H14C109.00H16D—C16B—H16E109.00
H14A—C14A—H14B110.00H16D—C16B—H16F109.00
H14A—C14A—H14C109.00H16E—C16B—H16F109.00
H14B—C14A—H14C109.00O3B—C18B—H18C110.00
C10A—C16A—H16A109.00O3B—C18B—H18D110.00
C10A—C16A—H16B109.00C19B—C18B—H18C110.00
H16A—C16A—H16C109.00C19B—C18B—H18D110.00
C10A—C16A—H16C110.00H18C—C18B—H18D108.00
H16A—C16A—H16B109.00C18B—C19B—H19D109.00
H16B—C16A—H16C109.00C18B—C19B—H19E109.00
C19A—C18A—H18B110.00C18B—C19B—H19F109.00
O3A—C18A—H18A110.00H19D—C19B—H19E109.00
O3A—C18A—H18B110.00H19D—C19B—H19F110.00
C19A—C18A—H18A110.00H19E—C19B—H19F109.00
C17A—O3A—C18A—C19A175.7 (5)N1A—C1A—C15A—N2A36.3 (4)
C18A—O3A—C17A—O2A5.6 (5)N1A—C1A—C15A—O4A143.6 (3)
C18A—O3A—C17A—C11A179.9 (3)C15A—C1A—C2A—C3A144.4 (3)
C18B—O3B—C17B—O2B8.9 (5)C1A—C2A—C3A—C8A37.6 (3)
C17B—O3B—C18B—C19B79.2 (4)C1A—C2A—C3A—C4A162.6 (3)
C18B—O3B—C17B—C11B176.1 (3)C8A—C3A—C4A—C5A46.1 (5)
C1A—N1A—C9A—O1A177.9 (3)C2A—C3A—C8A—C7A81.5 (3)
C8A—N1A—C1A—C2A1.3 (3)C4A—C3A—C8A—C7A45.3 (4)
C9A—N1A—C1A—C2A161.9 (3)C4A—C3A—C8A—N1A162.8 (3)
C8A—N1A—C9A—O1A16.6 (5)C2A—C3A—C8A—N1A36.0 (3)
C1A—N1A—C9A—C10A2.8 (5)C2A—C3A—C4A—C5A73.5 (4)
C9A—N1A—C8A—C7A65.4 (4)C3A—C4A—C5A—C6A52.8 (4)
C1A—N1A—C8A—C7A97.4 (3)C4A—C5A—C6A—C7A59.0 (5)
C9A—N1A—C8A—C3A175.2 (3)C5A—C6A—C7A—C8A59.6 (5)
C8A—N1A—C1A—C15A124.2 (3)C6A—C7A—C8A—C3A52.4 (4)
C8A—N1A—C9A—C10A164.1 (3)C6A—C7A—C8A—N1A164.9 (3)
C9A—N1A—C1A—C15A39.0 (4)O1A—C9A—C10A—C16A9.6 (5)
C1A—N1A—C8A—C3A22.0 (3)N1A—C9A—C10A—C16A171.0 (3)
C11A—N2A—C10A—C16A20.2 (5)N1A—C9A—C10A—N2A45.2 (4)
C15A—N2A—C10A—C16A171.8 (3)O1A—C9A—C10A—N2A135.5 (3)
C10A—N2A—C11A—C12A100.0 (4)N2A—C11A—C12A—C13A55.8 (4)
C11A—N2A—C15A—O4A4.9 (5)N2A—C11A—C17A—O3A39.4 (4)
C15A—N2A—C10A—C9A48.1 (4)C12A—C11A—C17A—O2A21.4 (5)
C11A—N2A—C10A—C9A143.9 (3)C17A—C11A—C12A—C13A179.1 (3)
C10A—N2A—C15A—C1A6.5 (4)N2A—C11A—C17A—O2A146.3 (3)
C11A—N2A—C15A—C1A175.1 (3)C12A—C11A—C17A—O3A164.3 (3)
C10A—N2A—C15A—O4A173.5 (3)C11A—C12A—C13A—C14A176.7 (4)
C15A—N2A—C11A—C17A53.4 (4)N1B—C1B—C15B—O4B135.4 (3)
C15A—N2A—C11A—C12A68.2 (4)N1B—C1B—C2B—C3B26.1 (3)
C10A—N2A—C11A—C17A138.4 (3)C15B—C1B—C2B—C3B144.9 (3)
C9B—N1B—C1B—C2B165.1 (3)N1B—C1B—C15B—N2B44.4 (4)
C8B—N1B—C9B—O1B9.8 (6)C2B—C1B—C15B—N2B160.6 (3)
C9B—N1B—C1B—C15B41.1 (4)C2B—C1B—C15B—O4B19.2 (4)
C1B—N1B—C9B—O1B174.8 (3)C1B—C2B—C3B—C4B165.1 (3)
C8B—N1B—C1B—C2B1.6 (4)C1B—C2B—C3B—C8B40.8 (3)
C1B—N1B—C8B—C7B96.9 (3)C4B—C3B—C8B—N1B166.3 (3)
C8B—N1B—C1B—C15B125.6 (3)C2B—C3B—C8B—N1B38.9 (3)
C1B—N1B—C8B—C3B23.6 (3)C4B—C3B—C8B—C7B46.9 (4)
C9B—N1B—C8B—C7B69.2 (4)C8B—C3B—C4B—C5B44.9 (5)
C8B—N1B—C9B—C10B171.3 (3)C2B—C3B—C8B—C7B80.5 (4)
C1B—N1B—C9B—C10B6.3 (4)C2B—C3B—C4B—C5B74.2 (4)
C9B—N1B—C8B—C3B170.3 (3)C3B—C4B—C5B—C6B50.7 (5)
C15B—N2B—C10B—C16B170.8 (3)C4B—C5B—C6B—C7B57.8 (5)
C11B—N2B—C15B—C1B178.9 (3)C5B—C6B—C7B—C8B59.9 (4)
C11B—N2B—C15B—O4B1.3 (4)C6B—C7B—C8B—C3B54.7 (4)
C11B—N2B—C10B—C16B9.6 (4)C6B—C7B—C8B—N1B168.0 (3)
C10B—N2B—C15B—O4B179.0 (3)O1B—C9B—C10B—N2B131.3 (3)
C15B—N2B—C10B—C9B47.2 (4)N1B—C9B—C10B—N2B49.8 (4)
C10B—N2B—C11B—C12B106.7 (3)N1B—C9B—C10B—C16B175.5 (3)
C11B—N2B—C10B—C9B133.1 (3)O1B—C9B—C10B—C16B5.6 (5)
C15B—N2B—C11B—C17B53.1 (4)N2B—C11B—C12B—C13B63.7 (4)
C10B—N2B—C11B—C17B127.3 (3)C17B—C11B—C12B—C13B172.2 (3)
C10B—N2B—C15B—C1B0.8 (4)N2B—C11B—C17B—O2B144.0 (3)
C15B—N2B—C11B—C12B72.9 (4)N2B—C11B—C17B—O3B40.8 (4)
C2A—C1A—C15A—O4A26.9 (4)C12B—C11B—C17B—O2B18.1 (4)
C2A—C1A—C15A—N2A153.1 (3)C12B—C11B—C17B—O3B166.7 (3)
N1A—C1A—C2A—C3A24.1 (3)C11B—C12B—C13B—C14B172.5 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C10A—H10A···O4B1.002.223.184 (4)161
C10B—H10B···O4Ai1.002.363.341 (4)165
C11A—H11A···O2Bii1.002.453.297 (4)142
C19B—H19E···O1Biii0.982.543.408 (5)148
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1/2, z+3/2; (iii) x1, y, z.
(It) Ethyl (2S)-2-[(3S,5aS,9aS,10aS)-3-methyl-1,4-dioxo-5a,6,7,8,9,9a,10,10a-octahydro-3H-pyrazino[1,2-a]indol-2-yl]pentanoate top
Crystal data top
C19H30N2O4Dx = 1.210 Mg m3
Mr = 350.45Cu Kα radiation, λ = 1.54178 Å
Tetragonal, P41212Cell parameters from 9913 reflections
Hall symbol: P 4abw 2nwθ = 3.9–71.7°
a = 9.2606 (8) ŵ = 0.68 mm1
c = 44.847 (4) ÅT = 100 K
V = 3846.0 (7) Å3Plate, colourless
Z = 80.45 × 0.40 × 0.20 mm
F(000) = 1520
Data collection top
Bruker APEXII CCD
diffractometer
3359 independent reflections
Radiation source: 30W microsource with MonoCap capillary3355 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.022
ω scanθmax = 66.0°, θmin = 3.9°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
h = 1010
Tmin = 0.772, Tmax = 0.872k = 108
39411 measured reflectionsl = 5353
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.039 w = 1/[σ2(Fo2) + (0.055P)2 + 1.8942P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.107(Δ/σ)max < 0.001
S = 1.05Δρmax = 0.44 e Å3
3359 reflectionsΔρmin = 0.26 e Å3
250 parametersExtinction correction: SHELXL, FC*=KFC[1+0.001XFC2Λ3/SIN(2Θ)]-1/4
13 restraintsExtinction coefficient: 0.00079 (13)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983), 1291 Friedel pairs
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 0.1 (2)
Crystal data top
C19H30N2O4Z = 8
Mr = 350.45Cu Kα radiation
Tetragonal, P41212µ = 0.68 mm1
a = 9.2606 (8) ÅT = 100 K
c = 44.847 (4) Å0.45 × 0.40 × 0.20 mm
V = 3846.0 (7) Å3
Data collection top
Bruker APEXII CCD
diffractometer
3359 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
3355 reflections with I > 2σ(I)
Tmin = 0.772, Tmax = 0.872Rint = 0.022
39411 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.039H-atom parameters constrained
wR(F2) = 0.107Δρmax = 0.44 e Å3
S = 1.05Δρmin = 0.26 e Å3
3359 reflectionsAbsolute structure: Flack (1983), 1291 Friedel pairs
250 parametersAbsolute structure parameter: 0.1 (2)
13 restraints
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating -R-factor-obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
O10.62988 (16)0.03979 (17)0.04593 (3)0.0413 (5)
O20.39233 (17)0.63530 (17)0.11258 (4)0.0441 (5)
O30.45637 (19)0.52133 (17)0.07042 (3)0.0467 (5)
O40.71201 (15)0.50032 (14)0.10981 (3)0.0294 (4)
N10.79170 (17)0.18912 (17)0.06767 (3)0.0258 (4)
N20.57318 (17)0.30308 (17)0.10164 (3)0.0266 (5)
C10.82940 (19)0.2842 (2)0.09277 (4)0.0245 (5)
C20.9579 (2)0.3705 (2)0.08089 (4)0.0281 (5)
C31.0289 (2)0.2638 (2)0.05915 (4)0.0271 (5)
C41.1428 (2)0.3266 (2)0.03803 (4)0.0307 (6)
C51.0800 (2)0.4071 (2)0.01127 (4)0.0357 (6)
C60.9664 (2)0.3172 (3)0.00445 (4)0.0369 (6)
C70.8426 (2)0.2823 (2)0.01698 (4)0.0334 (6)
C80.8986 (2)0.1945 (2)0.04342 (4)0.0271 (5)
C90.6646 (2)0.1196 (2)0.06639 (4)0.0285 (6)
C100.5676 (2)0.1465 (2)0.09365 (4)0.0266 (5)
C110.4486 (2)0.3808 (2)0.11428 (5)0.0328 (6)
C120.4602 (3)0.3994 (2)0.14839 (5)0.0397 (7)
C130.4814 (3)0.2604 (3)0.16523 (4)0.0513 (8)
C140.5036 (4)0.2894 (3)0.19837 (4)0.0649 (12)
C150.7002 (2)0.3735 (2)0.10207 (4)0.0249 (5)
C160.4165 (2)0.0917 (2)0.08769 (5)0.0342 (6)
C170.4315 (2)0.5276 (2)0.09973 (5)0.0333 (6)
C18A0.4387 (6)0.6446 (6)0.05262 (18)0.054 (2)0.521 (9)
C19A0.5933 (6)0.6999 (5)0.05042 (14)0.055 (2)0.521 (9)
C19B0.5623 (8)0.6557 (7)0.02783 (16)0.067 (3)0.479 (9)
C18B0.4772 (12)0.6563 (4)0.05692 (18)0.063 (3)0.479 (9)
H2B0.926300.457300.070700.0340*
H31.075800.188500.071100.0320*
H4A1.203900.392300.049200.0370*
H4B1.203300.248500.030800.0370*
H5A1.037200.497000.017900.0430*
H5B1.156900.430100.002600.0430*
H2A1.023500.396900.096800.0340*
H6B0.929300.369900.021500.0440*
H7A0.799600.371300.024100.0400*
H7B0.768800.227800.006600.0400*
H80.922900.096400.037000.0330*
H100.607200.091500.110400.0320*
H110.361500.324400.110000.0390*
H6A1.009400.228200.011600.0440*
H12B0.372900.445700.155600.0480*
H13A0.564800.209900.157300.0620*
H13B0.397500.199100.162500.0620*
H14D0.588900.346800.201100.0970*
H14E0.514400.199300.208700.0970*
H14F0.421500.340300.206100.0970*
H16A0.360100.098400.105600.0510*
H16B0.420800.007200.081300.0510*
H16C0.372500.149100.072400.0510*
H18A0.376000.714800.062100.0660*0.521 (9)
H18B0.400200.620200.033200.0660*0.521 (9)
H19A0.629000.721200.070000.0810*0.521 (9)
H19B0.595300.785900.038500.0810*0.521 (9)
H19C0.653000.627400.041400.0810*0.521 (9)
H12A0.540500.463200.152700.0480*
H10.861100.225100.109700.0290*
H18C0.526700.718600.071000.0750*0.479 (9)
H18D0.383200.698700.053100.0750*0.479 (9)
H19D0.656100.614600.031200.1000*0.479 (9)
H19E0.572800.752900.020700.1000*0.479 (9)
H19F0.511800.599200.013200.1000*0.479 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0326 (8)0.0483 (9)0.0431 (8)0.0083 (7)0.0003 (7)0.0183 (7)
O20.0393 (9)0.0342 (8)0.0588 (9)0.0097 (7)0.0025 (7)0.0052 (7)
O30.0557 (10)0.0446 (9)0.0398 (8)0.0176 (8)0.0090 (7)0.0027 (7)
O40.0281 (7)0.0279 (7)0.0321 (7)0.0006 (5)0.0012 (5)0.0048 (6)
N10.0233 (8)0.0273 (8)0.0268 (7)0.0000 (7)0.0014 (6)0.0032 (6)
N20.0199 (8)0.0273 (8)0.0327 (8)0.0016 (7)0.0005 (6)0.0011 (6)
C10.0207 (9)0.0271 (9)0.0257 (8)0.0003 (7)0.0026 (7)0.0015 (7)
C20.0248 (9)0.0306 (10)0.0288 (9)0.0030 (8)0.0007 (7)0.0029 (8)
C30.0256 (9)0.0265 (10)0.0291 (9)0.0045 (7)0.0019 (8)0.0001 (7)
C40.0260 (9)0.0316 (11)0.0346 (9)0.0010 (8)0.0035 (8)0.0046 (8)
C50.0382 (11)0.0332 (11)0.0357 (10)0.0037 (9)0.0100 (8)0.0020 (8)
C60.0306 (11)0.0527 (13)0.0273 (9)0.0076 (9)0.0035 (8)0.0035 (9)
C70.0259 (10)0.0454 (12)0.0290 (9)0.0046 (9)0.0002 (8)0.0022 (9)
C80.0234 (9)0.0275 (10)0.0303 (9)0.0023 (7)0.0017 (7)0.0048 (8)
C90.0245 (10)0.0292 (10)0.0319 (9)0.0023 (8)0.0048 (7)0.0018 (8)
C100.0225 (9)0.0239 (9)0.0334 (9)0.0002 (7)0.0037 (7)0.0010 (8)
C110.0229 (10)0.0304 (10)0.0451 (11)0.0051 (8)0.0017 (8)0.0006 (9)
C120.0359 (11)0.0354 (11)0.0479 (12)0.0083 (9)0.0107 (9)0.0007 (9)
C130.0683 (17)0.0351 (12)0.0506 (13)0.0031 (11)0.0205 (12)0.0006 (10)
C140.117 (3)0.0350 (13)0.0428 (13)0.0058 (14)0.0272 (15)0.0022 (10)
C150.0252 (9)0.0281 (10)0.0215 (8)0.0016 (8)0.0046 (7)0.0009 (7)
C160.0265 (10)0.0339 (11)0.0422 (11)0.0047 (8)0.0007 (8)0.0043 (9)
C170.0228 (10)0.0332 (11)0.0439 (11)0.0059 (8)0.0067 (8)0.0041 (9)
C18A0.056 (5)0.061 (4)0.046 (3)0.029 (3)0.014 (3)0.023 (3)
C19A0.069 (4)0.032 (3)0.063 (4)0.003 (2)0.004 (3)0.015 (2)
C19B0.078 (5)0.055 (4)0.067 (5)0.021 (3)0.010 (3)0.018 (3)
C18B0.047 (5)0.072 (6)0.070 (6)0.031 (4)0.006 (4)0.026 (4)
Geometric parameters (Å, º) top
O1—C91.221 (2)C3—H30.9800
O2—C171.208 (3)C4—H4A0.9700
O3—C171.336 (3)C4—H4B0.9700
O3—C18A1.403 (7)C5—H5A0.9700
O3—C18B1.402 (5)C5—H5B0.9700
O4—C151.230 (2)C6—H6A0.9700
N1—C11.471 (2)C6—H6B0.9700
N1—C81.472 (2)C7—H7A0.9700
N1—C91.343 (2)C7—H7B0.9700
N2—C101.495 (2)C8—H80.9800
N2—C111.473 (2)C10—H100.9800
N2—C151.345 (2)C11—H110.9800
C1—C21.529 (3)C12—H12A0.9700
C1—C151.513 (3)C12—H12B0.9700
C2—C31.536 (3)C13—H13A0.9700
C3—C41.532 (3)C13—H13B0.9700
C3—C81.538 (3)C14—H14D0.9600
C4—C51.528 (3)C14—H14E0.9600
C5—C61.516 (3)C14—H14F0.9600
C6—C71.531 (3)C16—H16A0.9600
C7—C81.528 (3)C16—H16B0.9600
C9—C101.537 (3)C16—H16C0.9600
C10—C161.512 (3)C18A—H18A0.9700
C11—C121.543 (3)C18A—H18B0.9700
C11—C171.516 (3)C18B—H18C0.9700
C12—C131.505 (3)C18B—H18D0.9700
C13—C141.524 (3)C19A—H19C0.9600
C18A—C19A1.524 (8)C19A—H19A0.9600
C18B—C19B1.524 (12)C19A—H19B0.9600
C1—H10.9800C19B—H19D0.9600
C2—H2A0.9700C19B—H19E0.9600
C2—H2B0.9700C19B—H19F0.9600
C17—O3—C18A120.3 (3)C5—C6—H6B110.00
C17—O3—C18B114.2 (3)C7—C6—H6A110.00
C1—N1—C8112.68 (14)C7—C6—H6B110.00
C1—N1—C9121.85 (15)H6A—C6—H6B108.00
C8—N1—C9125.05 (15)C6—C7—H7A110.00
C10—N2—C11122.63 (15)C6—C7—H7B110.00
C10—N2—C15120.27 (15)C8—C7—H7A110.00
C11—N2—C15116.26 (15)C8—C7—H7B110.00
N1—C1—C2103.35 (14)H7A—C7—H7B108.00
N1—C1—C15110.51 (14)N1—C8—H8110.00
C2—C1—C15115.20 (15)C3—C8—H8110.00
C1—C2—C3102.60 (15)C7—C8—H8110.00
C2—C3—C4116.29 (15)N2—C10—H10108.00
C2—C3—C8102.93 (15)C9—C10—H10108.00
C4—C3—C8114.51 (15)C16—C10—H10108.00
C3—C4—C5114.12 (15)N2—C11—H11108.00
C4—C5—C6111.20 (16)C12—C11—H11108.00
C5—C6—C7110.11 (15)C17—C11—H11108.00
C6—C7—C8110.20 (15)C11—C12—H12A109.00
N1—C8—C3101.71 (14)C11—C12—H12B109.00
N1—C8—C7111.29 (15)C13—C12—H12A109.00
C3—C8—C7113.58 (15)C13—C12—H12B109.00
O1—C9—N1123.58 (17)H12A—C12—H12B108.00
O1—C9—C10122.80 (17)C12—C13—H13A109.00
N1—C9—C10113.61 (15)C12—C13—H13B109.00
N2—C10—C9109.13 (14)C14—C13—H13A110.00
N2—C10—C16113.58 (15)C14—C13—H13B110.00
C9—C10—C16110.23 (15)H13A—C13—H13B108.00
N2—C11—C12112.42 (17)C13—C14—H14D109.00
N2—C11—C17110.75 (16)C13—C14—H14E109.00
C12—C11—C17109.50 (16)C13—C14—H14F109.00
C11—C12—C13114.27 (16)H14D—C14—H14E110.00
C12—C13—C14110.9 (2)H14D—C14—H14F110.00
O4—C15—N2123.02 (17)H14E—C14—H14F110.00
O4—C15—C1121.98 (17)C10—C16—H16A110.00
N2—C15—C1115.00 (16)C10—C16—H16B110.00
O2—C17—O3123.87 (19)C10—C16—H16C109.00
O2—C17—C11124.5 (2)H16A—C16—H16B109.00
O3—C17—C11111.50 (17)H16A—C16—H16C109.00
O3—C18A—C19A101.6 (4)H16B—C16—H16C109.00
O3—C18B—C19B115.9 (5)O3—C18A—H18A111.00
N1—C1—H1109.00O3—C18A—H18B111.00
C2—C1—H1109.00C19A—C18A—H18A111.00
C15—C1—H1109.00C19A—C18A—H18B111.00
C1—C2—H2A111.00H18A—C18A—H18B109.00
C1—C2—H2B111.00O3—C18B—H18D108.00
C3—C2—H2A111.00C19B—C18B—H18C108.00
C3—C2—H2B111.00C19B—C18B—H18D108.00
H2A—C2—H2B109.00H18C—C18B—H18D107.00
C2—C3—H3107.00O3—C18B—H18C108.00
C4—C3—H3108.00H19A—C19A—H19C109.00
C8—C3—H3108.00H19B—C19A—H19C110.00
C3—C4—H4A109.00C18A—C19A—H19A110.00
C3—C4—H4B109.00C18A—C19A—H19B109.00
C5—C4—H4A109.00C18A—C19A—H19C109.00
C5—C4—H4B109.00H19A—C19A—H19B109.00
H4A—C4—H4B108.00C18B—C19B—H19D110.00
C4—C5—H5A110.00C18B—C19B—H19E110.00
C4—C5—H5B109.00C18B—C19B—H19F110.00
C6—C5—H5A109.00H19D—C19B—H19E109.00
C6—C5—H5B109.00H19D—C19B—H19F109.00
H5A—C5—H5B108.00H19E—C19B—H19F109.00
C5—C6—H6A110.00
C17—O3—C18A—C19A97.5 (4)C15—C1—C2—C3150.98 (15)
C18A—O3—C17—O20.6 (4)N1—C1—C15—N239.3 (2)
C18A—O3—C17—C11176.7 (3)C2—C1—C15—N2155.96 (15)
C8—N1—C1—C28.57 (19)C2—C1—C15—O425.0 (2)
C9—N1—C8—C768.1 (2)C1—C2—C3—C4167.06 (15)
C1—N1—C9—O1179.90 (17)C1—C2—C3—C841.03 (17)
C8—N1—C9—O18.1 (3)C4—C3—C8—N1162.27 (15)
C1—N1—C9—C101.5 (2)C2—C3—C8—N135.11 (17)
C9—N1—C1—C2164.36 (16)C4—C3—C8—C742.6 (2)
C8—N1—C1—C15132.35 (16)C8—C3—C4—C541.2 (2)
C9—N1—C1—C1540.6 (2)C2—C3—C8—C784.57 (17)
C9—N1—C8—C3170.58 (17)C2—C3—C4—C578.8 (2)
C1—N1—C8—C7104.53 (17)C3—C4—C5—C650.0 (2)
C1—N1—C8—C316.75 (19)C4—C5—C6—C760.2 (2)
C8—N1—C9—C10173.52 (16)C5—C6—C7—C861.3 (2)
C11—N2—C10—C1623.4 (2)C6—C7—C8—C352.3 (2)
C10—N2—C11—C12100.56 (19)C6—C7—C8—N1166.37 (16)
C15—N2—C10—C16167.49 (16)O1—C9—C10—N2138.95 (18)
C11—N2—C10—C9146.83 (16)N1—C9—C10—N242.6 (2)
C15—N2—C10—C944.1 (2)N1—C9—C10—C16168.01 (16)
C11—N2—C15—O46.8 (3)O1—C9—C10—C1613.6 (3)
C10—N2—C15—C12.5 (2)N2—C11—C12—C1355.0 (3)
C11—N2—C15—C1172.25 (15)C17—C11—C12—C13178.5 (2)
C10—N2—C15—O4176.51 (16)N2—C11—C17—O2143.77 (19)
C15—N2—C11—C1753.9 (2)N2—C11—C17—O340.2 (2)
C15—N2—C11—C1268.9 (2)C12—C11—C17—O219.2 (3)
C10—N2—C11—C17136.59 (16)C12—C11—C17—O3164.71 (18)
N1—C1—C15—O4141.67 (17)C11—C12—C13—C14175.5 (2)
N1—C1—C2—C330.35 (17)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1···O4i0.982.583.403 (2)141
C10—H10···O4i0.982.303.218 (2)155
C19A—H19B···O1ii0.962.403.172 (5)138
Symmetry codes: (i) x+3/2, y1/2, z+1/4; (ii) x, y+1, z.

Experimental details

(Io)(It)
Crystal data
Chemical formulaC19H30N2O4C19H30N2O4
Mr350.45350.45
Crystal system, space groupOrthorhombic, P212121Tetragonal, P41212
Temperature (K)100100
a, b, c (Å)9.2089 (10), 17.9875 (17), 23.697 (2)9.2606 (8), 9.2606 (8), 44.847 (4)
α, β, γ (°)90, 90, 9090, 90, 90
V3)3925.3 (7)3846.0 (7)
Z88
Radiation typeCu KαCu Kα
µ (mm1)0.670.68
Crystal size (mm)0.50 × 0.15 × 0.100.45 × 0.40 × 0.20
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Bruker APEXII CCD
diffractometer
Absorption correctionMulti-scan
SADABS (Sheldrick, 2003)
Multi-scan
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.886, 0.9350.772, 0.872
No. of measured, independent and
observed [I > 2σ(I)] reflections
39028, 6791, 5706 39411, 3359, 3355
Rint0.0430.022
(sin θ/λ)max1)0.5930.593
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.057, 0.145, 1.12 0.039, 0.107, 1.05
No. of reflections67913359
No. of parameters458250
No. of restraints013
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.46, 0.370.44, 0.26
Absolute structureFlack (1983), 2958 Friedel pairsFlack (1983), 1291 Friedel pairs
Absolute structure parameter0.1 (3)0.1 (2)

Computer programs: APEX2 (Bruker, 2005), SAINT-Plus (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and Mercury (Macrae et al., 2008), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) for (Io) top
D—H···AD—HH···AD···AD—H···A
C10A—H10A···O4B1.002.223.184 (4)161
C10B—H10B···O4Ai1.002.363.341 (4)165
C11A—H11A···O2Bii1.002.453.297 (4)142
C19B—H19E···O1Biii0.982.543.408 (5)148
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1/2, z+3/2; (iii) x1, y, z.
Hydrogen-bond geometry (Å, º) for (It) top
D—H···AD—HH···AD···AD—H···A
C1—H1···O4i0.982.583.403 (2)141
C10—H10···O4i0.982.303.218 (2)155
C19A—H19B···O1ii0.962.403.172 (5)138
Symmetry codes: (i) x+3/2, y1/2, z+1/4; (ii) x, y+1, z.
The ring-puckering parameters of orthorhombic (Io) and tetragonal (It) polymorphs (Cremer &amp; Pople, 1975; Spek, 2009). top
Six-membered ringProline ringDiketopiperazine ring
(Io), molecule Aϕ = 359 (2)°, θ = 169.6 (4)°ϕ = 284.9 (5)°ϕ = 59.9 (3)°, θ = 94.6 (3)°
(Io), molecule Aϕ = 17 (2)°, θ = 169.0 (4)°ϕ = 284.7 (5)°ϕ = 65.2 (3)°, θ = 93.0 (3)°
(It)ϕ = 7.2 (8)°, θ = 165.1 (2)°ϕ = 275.7 (3)°ϕ = 61.71 (18)°, θ = 92.28 (19)°
Torsion angles (°) of the alkyl chains in polymorphs (Io) and (It) top
(Io), molecule A(Io), molecule B(It), conformer A(It), conformer B
C10—N2—C11—C12100.0 (4)106.7 (3)100.56 (19)
C10—N2—C11—C17-138.4 (3)-127.3 (3)-136.60 (16)
C11—C12—C13—C14176.7 (4)172.5 (4)175.5 (2)
C12—C11—C17—O2-21.4 (5)-18.1 (4)-19.3 (3)
C12—C11—C17—O3164.3 (3)166.7 (3)164.72 (18)
N2—C11—C17—O2-146.3 (3)-144.0 (3)-143.78 (19)
N2—C11—C17—O339.4 (4)40.8 (4)40.2 (2)
N2—C11—C12—C13-55.8 (4)-63.7 (4)-55.0 (3)
C17—O3—C18—C19175.7 (5)79.2 (4)97.5 (4)156.5 (6)
C17—C11—C12—C13-179.1 (3)172.2 (3)-178.5 (2)
C18—O3—C17—O25.6 (5)8.9 (5)0.6 (4)18.7 (6)
C18—O3—C17—C11179.9 (3)-176.1 (3)176.7 (3)-165.2 (5)
 

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