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tert-Butoxy­carbonyl­glycyl-dehydro­alanyl-glycine methyl ester (systematic name: methyl {2-[(tert-butoxycarbonylamino)­acetamido]prop-2-enamido}acetate) (Boc0-Gly1-ΔAla2-Gly3-OMe), C13H21N3O6, has been structurally characterized by single-crystal X-ray diffraction and by density functional theory (DFT) calculations at the B3LYP/6–311+G** level. The peptide chain in both the solid-state and calculated structures adopts neither β nor γ turns. All amino acid residues in the tripeptide sequence are linked trans to each other. The bond lengths and valence angles of the amino acid units in the crystal structure and gas phase are comparable. However, the conformation of the third glycyl residue (Gly3) is different in the crystalline state and in the gas phase. It is stabilized in the calculated structure by an additional intra­molecular short contact between Gly3 NH and methyl ester COMe groups.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270106052590/av3051sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270106052590/av3051Isup2.hkl
Contains datablock I

CCDC reference: 604222

Comment top

The α,β-dehydroamino acids in peptides have been found to be responsible for the formation of derivatives of natural peptides with interesting biological activities (Jain & Chauhan, 1996). This is mainly based on the presence of a CαCβ double bond, which gives not only a specific chemical property, but also an inherent conformational preference. Therefore, α,β-dehydroamino acid residues attract much interest as a significant element in secondary structure design (helices, sheets and turns) in peptides. Apart from the presence of the CαCβ bond, which introduces steric repulsions, an important role is also played by intramolecular N—H···O, N—H···N and C—H···O hydrogen bonds and N—H···π-electron cross conjugation (Sigh & Kaur, 1997; Venkatachalam, 1968; Perczel et al., 1996; Vass et al., 2003).

The title methyl ester, Boc0–Gly1–ΔAla2–Gly3–OMe, (I), represents an example of a peptide with a rigid central amino acid (ΔAla) placed between two flexible glycine residues. Dehydroalanine (ΔAla) is the simplest and most widespread α,β-dehydroamino acid. The insertion of such a small molecule into a peptide chain may significantly change its properties, e.g. the insertion of a ΔAla residue into the chains of the tripeptides Gly-ΔAla-Gly and Gly-ΔAla-Phe or the tetrapeptides Gly-ΔAla-Phe-Gly and Gly-Gly-ΔAla-Phe has an influence on the binding abilities of these peptide ligands towards copper(II) ions (Świ\,atek-Kozłowska et al., 2000). Another example is the Gly-ΔAla-Gly-Phe-pNA tetrapeptide, which acts as a substrate of dipeptidyl-peptidase (cathepsin C), representing comparable activity to their classical counterparts (Makowski et al., 2001).

ΔAla adopts an almost planar conformation, with a trans orientation for the ϕ and ψ torsion angles, and induces an inverse γ turn in the preceding residue. Similar effects were observed for linear dehydroalanine-containing peptides in solution or in the crystal state. It seems that dehydroalanine exerts a powerful conformational influence independently of other constraints (Palmer et al., 1992). A number of theoretical calculations have been devoted to the conformational preferences of ΔAla (e.g. Crisma et al., 1999; Füzéry & Csizmadia, 2000; Rzeszotarska et al., 2002; Siodłak et al., 2004; Broda et al., 2005). All these studies provide evidence that the fully extended conformation (C5) is preferred by the ΔAla residue, with the ϕ, ψ and ω backbone torsion angles very close to the trans orientation. This structure is stabilized by two types of intramolecular hydrogen bonds: Ni—H···OiCi, with a five-membered ring C5 form, and CBi+1—H···OiCi, giving rise to a six-membered ring system. The conformational map calculated for Ac-ΔAla-NHMe reveals four minima located at values of the ϕ and ψ angles of around 180 or 0°. The lowest-energy conformer presents the fully extended structure, with ϕ and ψ torsion angles of 180 and 169°, respectively.

The conformation of (I) in the crystal structure, with the atom-numbering scheme, is shown in Fig. 1. This conformation is stabilized by both inter- and intramolecular hydrogen bonds and short contacts, and details of these are given in Tables 1 and 3. The similar tripeptide Boc-Gly-ΔPhe-Gly-OMe forms a type IIβ turn, with an intramolecular N—H···O hydrogen bond between the third and first peptide units. The C1α···C3α distance is 5.387 (4) Å (Główka, 1988). The analogous distance in (I) is 7.038 (2) Å, which is insufficient for considering the secondary structure of (I) as a β turn. Additionally, the 14 (C10) and 13 (C7) intramolecular hydrogen bonds, which are characteristic for β and γ turns, respectively, are not present.

The calculated conformation of (I) is shown in Fig. 2. This is the lowest-energy conformation of this compound in the gas phase. On the basis of the hydrogen-bonding backbone and the values of the ϕ and ψ torsion angles, the conformation of (I) in the gas phase could not be assigned to either β or γ turns. Table 2 lists the bond lengths and angles of the title compound in the crystal structure and calculated by the DFT method. All bond distances and valence angles are in good agreement with those observed in other peptides containing the ΔAla and Gly residues (Crisma et al., 1999; Rzeszotarska et al., 2002; Ajo et al., 1979; Palmer et al., 1992; Padmanabhan et al., 1992; Piazzesi et al., 1993). There are no significant differences between the bond lengths and angles of this tripeptide in the solid state and in the calculated structure; the differences do not exceed 0.04 Å for bond distances and 2° for bond angles.

In both the solid state and gas phase, the Gly1-ΔAla2 fragment of (I) adopts the fully extended conformation, with ϕ and ψ angles of around 180 and -170°, respectively. The planarity of this fragment is stabilized by intramolecular C14—H14B···O11, N12—H12···O16 and N12—H12···N8 hydrogen bonds and short contacts. Additionally, the co-planarity of the Gly1-ΔAla2 residue favours π-conjugation of the C13C14 double bond with neighbouring amide bonds.

The differences between both the solid state and the gas phase of (I) become clearly visible when the torsion angles and intermolecular hydrogen bonds are considered. There are two places in the structure where these differences are particularly marked. One of these is the Gly1 residue. The value of ϕ1 which characterizes this residue increases from 89.0 (1)° in the crystal structure to 116° in the gas phase. More significant differences in conformation are observed in the Gly3 residue. The value of the C15—N17—C18—C19 torsion angle which characterizes this residue in the crystal structure is 69.7 (1)°, while in the gas phase this angle increases by more than 100° to 176.84°, due to the fact that the Gly3 and OMe residues become nearly coplanar. This conformational change is stabilized by an intramolecular N17—H17···O21 short contact (Table 3) observed only in the calculated structure.

Because of many competitive intermolecular hydrogen bonds, in the crystal structure of (I) there is a relatively large rotation of the N17—C18 bond (over 100°) and a slightly lower rotation of the C18—C19 bond. A relatively strong N17—H17···O7ii hydrogen bond (which causes the molecules to arrange in a head-to-tail fashion) is present in the crystal structure of (I), as well as two others, C18—H18A···O11ii and C18—H18B···O20iv. Apart from these hydrogen bonds, there are also other intermolecular interactions, but only these hydrogen bonds cause the non-planarity of this residue in the crystal structure.

In similar compounds which contain the Gly-OMe residue, such as ethyl (4-bromo-1H-pyrrole-2-carboxamido)acetate (Zeng, 2005), N-(tert-butoxycarbonylglycyl-(Z)-α,β-dehydrophenylalanylglycyl-(E)-α,β- dehydrophenylalanyl)glycine methyl ester dihydrate (Makowski et al., 2006), 4,5-bis[(ethoxyglycyl)carbonyl]-1H-imidazole and 4-ethoxycarbonyl-5-([(methoxyglycyl)carbonyl]-1H-imidazole (Baures et al., 2003) and tert-butoxycarbonyl-glycyl-dehydrophenylalanyl-glycine methyl ester (Główka, 1988), the analogous torsion angles are -66.67, 135.24, 94.62, -92.24 and 71.67°, respectively. This indicates that this fragment is usually twisted in the crystal structure.

There were several instances in the Comment where the meaning was not clear. Please check that the rephrasing has not misconstrued anything.

Related literature top

For related literature, see: Ajo et al. (1979); Baures et al. (2003); Becke (1988, 1993); Broda et al. (2005); Crisma et al. (1999); Füzéry & Csizmadia (2000); Frisch (2004); Główka (1988); Jain & Chauhan (1996); Lee et al. (1988); Makowski et al. (1986, 2001, 2006); Padmanabhan et al. (1992); Palmer et al. (1992); Perczel et al. (1996); Piazzesi et al. (1993); Rzeszotarska et al. (2002); Sigh & Kaur (1997); Siodłak et al. (2004); Vass et al. (2003); Venkatachalam (1968); Zeng (2005); Świ\,atek-Kozłowska, Brasuń, Chruściński, Chruścińska, Makowski & Kozłowski (2000).

Experimental top

The title compound was synthesized by the reaction of Boc-Gly-ΔAla (after activation with N,N'-dicyclohexylcarbodiimide and 1-hydroxybenzotriazole) with Gly-OMe at room temperature for 24 h (Makowski et al., 1986). Crystals of (I) suitable for X-ray crystal structure analysis were grown from a CHCl3–MeOH (1:1)–hexane [Please give ratio of all three components] solution.

Refinement top

The geometry of (I) in the crystal state was used as the starting structure for full optimization using standard density functional theory (DFT) employing the B3LYP hybrid function (Becke, 1988; Lee et al., 1988; Becke, 1993) at the 6–311+G** level of theory, with no imaginary frequencies. The calculations were carried out using GAUSSIAN03 (Frisch et al., 2004). H atoms were located in a difference Fourier map and refined freely; refined C—H and N—H distances are in the ranges ?–? Å and ?–? Å, respectively [Please complete].

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2002); cell refinement: CrysAlis RED (Oxford Diffraction, 2002); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1990); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), showing the intra- and intermolecular hydrogen-bonding scheme (dashed lines). Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. [(i) 1 - x, 1 - y, -z; (ii) -x, 1 - y, -z; (iii) 1 - x, 2 - y, -z; (iv) -x, 1 - y, -1 - z; (v) x, y, z - 1.]
[Figure 2] Fig. 2. The molecular structure of (I) calculated by DFT, showing the intra- and intermolecular hydrogen-bonding scheme (dashed lines). Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
tert-Butoxycarbonylglycyl-dehydroalanyl-glycine methyl ester top
Crystal data top
C13H21N3O6Z = 2
Mr = 315.33F(000) = 336
Triclinic, P1Dx = 1.370 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 8.6343 (14) ÅCell parameters from 7435 reflections
b = 8.7713 (14) Åθ = 3.4–26.0°
c = 11.2379 (15) ŵ = 0.11 mm1
α = 110.158 (13)°T = 100 K
β = 98.428 (12)°Cube, colourless
γ = 100.631 (14)°0.51 × 0.48 × 0.46 mm
V = 764.6 (2) Å3
Data collection top
Oxford Xcalibur
diffractometer
2676 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.022
Graphite monochromatorθmax = 26.0°, θmin = 3.4°
Detector resolution: 1024x1024 with blocks 2x2 pixels mm-1h = 610
ω scansk = 1010
7435 measured reflectionsl = 1313
3000 independent reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.031All H-atom parameters refined
wR(F2) = 0.082 w = 1/[σ2(Fo2) + (0.0442P)2 + 0.1565P]
where P = (Fo2 + 2Fc2)/3
S = 1.08(Δ/σ)max < 0.001
3000 reflectionsΔρmax = 0.23 e Å3
284 parametersΔρmin = 0.21 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.021 (3)
Crystal data top
C13H21N3O6γ = 100.631 (14)°
Mr = 315.33V = 764.6 (2) Å3
Triclinic, P1Z = 2
a = 8.6343 (14) ÅMo Kα radiation
b = 8.7713 (14) ŵ = 0.11 mm1
c = 11.2379 (15) ÅT = 100 K
α = 110.158 (13)°0.51 × 0.48 × 0.46 mm
β = 98.428 (12)°
Data collection top
Oxford Xcalibur
diffractometer
2676 reflections with I > 2σ(I)
7435 measured reflectionsRint = 0.022
3000 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0310 restraints
wR(F2) = 0.082All H-atom parameters refined
S = 1.08Δρmax = 0.23 e Å3
3000 reflectionsΔρmin = 0.21 e Å3
284 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) 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
C10.63869 (16)1.12041 (16)0.38517 (12)0.0271 (3)
C20.75416 (15)1.04655 (17)0.18817 (15)0.0289 (3)
C30.45946 (15)1.02527 (16)0.16322 (12)0.0233 (3)
C40.60829 (13)1.01074 (14)0.24325 (11)0.0195 (2)
O50.59474 (9)0.83523 (10)0.22956 (8)0.01989 (19)
C60.47197 (12)0.74786 (14)0.25705 (10)0.0163 (2)
O70.35847 (9)0.79777 (10)0.29474 (7)0.01881 (18)
N80.49033 (11)0.59243 (12)0.23623 (9)0.0175 (2)
C90.38542 (13)0.47449 (14)0.26990 (11)0.0184 (2)
C100.23509 (13)0.36330 (13)0.16559 (11)0.0171 (2)
O110.14065 (10)0.25943 (10)0.18581 (8)0.0233 (2)
N120.21658 (11)0.39351 (12)0.05533 (9)0.0173 (2)
C130.08327 (13)0.32448 (14)0.05007 (10)0.0174 (2)
C140.04576 (14)0.20692 (16)0.06441 (12)0.0254 (3)
C150.10913 (12)0.40105 (13)0.14789 (10)0.0161 (2)
O160.24164 (9)0.49336 (10)0.13541 (7)0.01866 (19)
N170.01318 (11)0.36630 (12)0.24765 (9)0.0176 (2)
C180.01102 (14)0.44023 (14)0.34205 (11)0.0193 (2)
C190.12270 (13)0.37226 (14)0.42596 (10)0.0176 (2)
O200.22079 (10)0.45815 (11)0.45697 (8)0.0258 (2)
O210.09356 (10)0.20685 (10)0.46601 (8)0.02215 (19)
C220.18710 (17)0.13081 (17)0.55562 (13)0.0277 (3)
H1A0.5519 (17)1.0885 (17)0.4240 (14)0.024 (3)*
H1B0.6533 (16)1.2382 (19)0.3924 (14)0.028 (4)*
H1C0.7411 (19)1.1103 (19)0.4333 (15)0.035 (4)*
H2A0.7741 (18)1.162 (2)0.1904 (15)0.033 (4)*
H2B0.7367 (19)0.967 (2)0.0967 (17)0.039 (4)*
H2C0.8465 (19)1.0376 (19)0.2414 (15)0.033 (4)*
H3A0.3694 (17)1.0332 (18)0.2073 (14)0.027 (3)*
H3B0.4895 (17)1.130 (2)0.1476 (14)0.031 (4)*
H3C0.4217 (17)0.930 (2)0.0809 (15)0.030 (4)*
H80.5779 (18)0.5710 (18)0.2120 (14)0.026 (3)*
H9A0.3497 (16)0.5323 (17)0.3446 (14)0.021 (3)*
H9B0.4463 (16)0.4000 (17)0.2900 (13)0.022 (3)*
H120.2932 (16)0.4678 (17)0.0479 (13)0.019 (3)*
H14A0.1327 (18)0.1679 (19)0.1421 (15)0.031 (4)*
H14B0.0581 (18)0.1575 (19)0.0008 (15)0.033 (4)*
H170.1094 (18)0.3104 (18)0.2529 (14)0.026 (4)*
H18A0.0535 (16)0.5606 (18)0.3003 (13)0.021 (3)*
H18B0.0929 (17)0.4159 (18)0.3998 (14)0.027 (3)*
H22A0.1760 (17)0.1631 (18)0.6300 (15)0.030 (4)*
H22B0.1436 (19)0.010 (2)0.5822 (16)0.039 (4)*
H22C0.302 (2)0.167 (2)0.5113 (15)0.037 (4)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0311 (7)0.0204 (6)0.0241 (6)0.0007 (5)0.0008 (5)0.0068 (5)
C20.0217 (6)0.0264 (7)0.0420 (8)0.0027 (5)0.0115 (5)0.0173 (6)
C30.0230 (6)0.0235 (6)0.0239 (6)0.0046 (5)0.0044 (5)0.0107 (5)
C40.0186 (5)0.0148 (5)0.0239 (6)0.0015 (4)0.0043 (4)0.0076 (4)
O50.0166 (4)0.0161 (4)0.0274 (4)0.0029 (3)0.0073 (3)0.0085 (3)
C60.0140 (5)0.0181 (5)0.0132 (5)0.0006 (4)0.0002 (4)0.0048 (4)
O70.0163 (4)0.0204 (4)0.0198 (4)0.0047 (3)0.0054 (3)0.0073 (3)
N80.0141 (4)0.0178 (5)0.0206 (5)0.0036 (4)0.0051 (4)0.0071 (4)
C90.0187 (5)0.0178 (5)0.0192 (6)0.0038 (4)0.0041 (4)0.0085 (4)
C100.0176 (5)0.0161 (5)0.0192 (5)0.0063 (4)0.0066 (4)0.0067 (4)
O110.0229 (4)0.0232 (4)0.0239 (4)0.0003 (3)0.0047 (3)0.0122 (4)
N120.0144 (4)0.0188 (5)0.0172 (5)0.0006 (4)0.0040 (3)0.0069 (4)
C130.0164 (5)0.0190 (5)0.0159 (5)0.0052 (4)0.0048 (4)0.0048 (4)
C140.0196 (6)0.0313 (7)0.0230 (6)0.0017 (5)0.0016 (5)0.0130 (5)
C150.0158 (5)0.0154 (5)0.0167 (5)0.0059 (4)0.0071 (4)0.0035 (4)
O160.0155 (4)0.0203 (4)0.0202 (4)0.0034 (3)0.0057 (3)0.0078 (3)
N170.0148 (5)0.0206 (5)0.0173 (5)0.0031 (4)0.0047 (3)0.0073 (4)
C180.0197 (5)0.0187 (6)0.0202 (6)0.0054 (4)0.0035 (4)0.0084 (5)
C190.0184 (5)0.0194 (5)0.0149 (5)0.0031 (4)0.0003 (4)0.0088 (4)
O200.0270 (4)0.0252 (4)0.0266 (5)0.0018 (3)0.0089 (3)0.0130 (4)
O210.0289 (4)0.0187 (4)0.0229 (4)0.0078 (3)0.0121 (3)0.0094 (3)
C220.0365 (7)0.0291 (7)0.0250 (6)0.0161 (6)0.0151 (5)0.0120 (5)
Geometric parameters (Å, º) top
C1—C41.5048 (17)C10—O111.2122 (13)
C1—H1A0.966 (14)C10—N121.3473 (14)
C1—H1B0.990 (15)N12—C131.3940 (14)
C1—H1C1.002 (16)N12—H120.874 (14)
C2—C41.5115 (16)C13—C141.3188 (16)
C2—H2A0.984 (16)C13—C151.4950 (15)
C2—H2B0.995 (17)C14—H14A0.975 (15)
C2—H2C0.956 (16)C14—H14B0.964 (16)
C3—C41.5090 (16)C15—O161.2317 (13)
C3—H3A0.982 (14)C15—N171.3281 (14)
C3—H3B0.989 (16)N17—C181.4417 (14)
C3—H3C0.969 (16)N17—H170.866 (15)
C4—O51.4739 (13)C18—C191.5052 (16)
O5—C61.3288 (13)C18—H18A0.967 (14)
C6—O71.2181 (13)C18—H18B0.967 (15)
C6—N81.3450 (15)C19—O201.1993 (14)
N8—C91.4347 (14)C19—O211.3240 (14)
N8—H80.871 (15)O21—C221.4441 (14)
C9—C101.5196 (16)C22—H22A0.968 (16)
C9—H9A0.947 (14)C22—H22B0.981 (17)
C9—H9B0.973 (14)C22—H22C0.984 (16)
C4—C1—H1A112.0 (8)H9A—C9—H9B108.6 (11)
C4—C1—H1B107.8 (8)O11—C10—N12124.81 (10)
H1A—C1—H1B111.2 (12)O11—C10—C9120.22 (10)
C4—C1—H1C109.3 (9)N12—C10—C9114.95 (9)
H1A—C1—H1C108.1 (12)C10—N12—C13127.46 (10)
H1B—C1—H1C108.4 (12)C10—N12—H12118.5 (9)
C4—C2—H2A109.5 (9)C13—N12—H12114.0 (9)
C4—C2—H2B110.9 (9)C14—C13—N12125.94 (11)
H2A—C2—H2B109.1 (13)C14—C13—C15124.30 (10)
C4—C2—H2C108.6 (9)N12—C13—C15109.74 (9)
H2A—C2—H2C108.5 (13)C13—C14—H14A119.2 (9)
H2B—C2—H2C110.2 (13)C13—C14—H14B122.6 (9)
C4—C3—H3A113.4 (8)H14A—C14—H14B118.2 (12)
C4—C3—H3B107.4 (8)O16—C15—N17121.43 (10)
H3A—C3—H3B107.3 (12)O16—C15—C13120.12 (10)
C4—C3—H3C110.8 (9)N17—C15—C13118.45 (9)
H3A—C3—H3C108.1 (12)C15—N17—C18118.66 (9)
H3B—C3—H3C109.8 (12)C15—N17—H17122.0 (9)
O5—C4—C1109.25 (9)C18—N17—H17119.0 (9)
O5—C4—C3110.65 (9)N17—C18—C19114.34 (9)
C1—C4—C3112.36 (10)N17—C18—H18A111.1 (8)
O5—C4—C2102.05 (9)C19—C18—H18A107.7 (8)
C1—C4—C2111.44 (10)N17—C18—H18B107.8 (8)
C3—C4—C2110.61 (10)C19—C18—H18B106.9 (9)
C6—O5—C4122.19 (8)H18A—C18—H18B108.9 (12)
O7—C6—O5126.23 (10)O20—C19—O21124.61 (10)
O7—C6—N8124.15 (10)O20—C19—C18123.44 (10)
O5—C6—N8109.62 (9)O21—C19—C18111.86 (9)
C6—N8—C9122.44 (9)C19—O21—C22115.14 (9)
C6—N8—H8116.6 (9)O21—C22—H22A111.5 (9)
C9—N8—H8120.3 (9)O21—C22—H22B104.8 (10)
N8—C9—C10116.01 (9)H22A—C22—H22B111.1 (13)
N8—C9—H9A109.8 (8)O21—C22—H22C109.7 (9)
C10—C9—H9A106.9 (8)H22A—C22—H22C108.1 (12)
N8—C9—H9B108.5 (8)H22B—C22—H22C111.6 (13)
C10—C9—H9B106.8 (8)
C1—C4—O5—C667.61 (12)C10—N12—C13—C15176.28 (10)
C3—C4—O5—C656.60 (13)C14—C13—C15—O16170.24 (11)
C2—C4—O5—C6174.33 (10)N12—C13—C15—O168.49 (13)
C4—O5—C6—O70.50 (16)C14—C13—C15—N179.42 (16)
C4—O5—C6—N8179.88 (9)N12—C13—C15—N17171.84 (9)
O7—C6—N8—C96.82 (16)O16—C15—N17—C180.52 (15)
O5—C6—N8—C9173.55 (9)C13—C15—N17—C18179.82 (9)
C6—N8—C9—C1088.99 (13)C15—N17—C18—C1969.74 (13)
N8—C9—C10—O11179.49 (10)N17—C18—C19—O20140.05 (11)
N8—C9—C10—N122.04 (14)N17—C18—C19—O2143.13 (13)
O11—C10—N12—C135.83 (18)O20—C19—O21—C221.55 (16)
C9—C10—N12—C13172.56 (10)C18—C19—O21—C22175.23 (9)
C10—N12—C13—C145.01 (19)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N8—H8···O16i0.87 (2)1.97 (2)2.834 (1)173 (1)
N17—H17···O7ii0.87 (2)2.10 (2)2.944 (1)167 (1)
C1—H1B···O20iii0.99 (2)2.48 (2)3.434 (2)161 (1)
C14—H14A···O7ii0.98 (2)2.54 (2)3.439 (2)154 (1)
C18—H18A···O11ii0.97 (1)2.68 (1)3.240 (2)117.6 (9)
C18—H18B···O20iv0.97 (2)2.49 (2)3.259 (1)137 (1)
C22—H22A···O11v0.97 (2)2.49 (2)3.459 (2)177 (1)
Symmetry codes: (i) x+1, y+1, z; (ii) x, y+1, z; (iii) x+1, y+2, z; (iv) x, y+1, z1; (v) x, y, z1.

Experimental details

Crystal data
Chemical formulaC13H21N3O6
Mr315.33
Crystal system, space groupTriclinic, P1
Temperature (K)100
a, b, c (Å)8.6343 (14), 8.7713 (14), 11.2379 (15)
α, β, γ (°)110.158 (13), 98.428 (12), 100.631 (14)
V3)764.6 (2)
Z2
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.51 × 0.48 × 0.46
Data collection
DiffractometerOxford Xcalibur
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
7435, 3000, 2676
Rint0.022
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.082, 1.08
No. of reflections3000
No. of parameters284
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.23, 0.21

Computer programs: CrysAlis CCD (Oxford Diffraction, 2002), CrysAlis RED (Oxford Diffraction, 2002), CrysAlis RED, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Sheldrick, 1990), SHELXL97.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N8—H8···O16i0.87 (2)1.97 (2)2.834 (1)173 (1)
N17—H17···O7ii0.87 (2)2.10 (2)2.944 (1)167 (1)
C1—H1B···O20iii0.99 (2)2.48 (2)3.434 (2)161 (1)
C14—H14A···O7ii0.98 (2)2.54 (2)3.439 (2)154 (1)
C18—H18A···O11ii0.97 (1)2.68 (1)3.240 (2)117.6 (9)
C18—H18B···O20iv0.97 (2)2.49 (2)3.259 (1)137 (1)
C22—H22A···O11v0.97 (2)2.49 (2)3.459 (2)177 (1)
Symmetry codes: (i) x+1, y+1, z; (ii) x, y+1, z; (iii) x+1, y+2, z; (iv) x, y+1, z1; (v) x, y, z1.
Comparison of selected geometric data for (I) (Å, °) from X-ray and calculated (DFT) data top
Distance or AngleX-rayDFT
C6-N81.345 (2)1.377
N8-C91.435 (1)1.449
C9-C101.520 (2)1.535
C10-O111.212 (1)1.219
C10-N121.347 (1)1.367
N12-C131.394 (1)1.398
C13-C141.319 (2)1.341
C13-C151.495 (2)1.513
C15-O161.232 (1)1.228
C15-N171.328 (1)1.355
N17-C181.442 (1)1.451
O11-C10-N12124.8 (1)124.88
O11-C10-C9120.2 (1)119.98
N12-C10-C9114.95 (9)115.14
C10-N12-C13127.5 (1)128.05
C14-C13-N12125.9 (1)125.97
C14-C13-C15124.3 (1)124.30
N12-C13-C15109.74 (9)109.70
O16-C15-N17121.4 (1)122.17
O16-C15-C13120.1 (1)120.26
N17-C15-C13118.45 (9)117.57
C15-N17-C18118.66 (9)120.57
N17-C18-C19114.34 (9)113.79
O5-C6-N8-C9 ω0173.55 (9)169.68
C6-N8-C9-C10 ϕ189.0 (1)116.90
N8-C9-C10-N12 ψ1-2.0 (1)-14.38
C9-C10-N12-C13 ω1-172.6 (1)-179.52
C10-N12-C13-C15 ϕ2176.3 (1)179.97
N12-C13-C15-N17 ψ2-171.84 (9)-166.48
O16-C15-N17-C18-0.5 (2)0.09
C13-C15-N17-C18 ω2179.82 (9)179.78
C15-N17-C18-C19 ϕ369.7 (1)176.84
N17-C18-C19-O20-140.0 (1)-176.61
N17-C18-C19-O21 ψ343.1 (1)3.88
Intramolecular hydrogen-bonding and short-contact geometry in (I) (Å, °) *X-ray, **DFT. top
D-H···AD-HH···AD···AD-H···A
N12-H12···O16*0.87 (1)2.14 (1)2.602 (1)112 (1)
**1.022.122.63109
N12-H12···N8*0.87 (1)2.29 (1)2.718 (1)110 (1)
**1.022.302.73108
C1-H1A···O7*0.97 (1)2.56 (1)3.109 (2)116 (1)
**1.092.463.052113
C3-H3A···O7*0.98 (1)2.57 (1)2.949 (2)103.1 (9)
**1.092.463.049113
C14-H14B···O11*0.96 (2)2.29 (2)2.867 (2)118 (1)
**1.081.262.910117
N17-H17···O21**1.012.192.628105
 

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