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The title compounds, C22H22N4 and C24H26N4O2 [alternative names: 2,6-dibenzyl-2,3,6,7-tetrahydro-1H,5H-dipyrrolo[3,4-b; 3′,4′-e]pyrazine and 2,6-bis(4-methoxybenzyl)-2,3,6,7-tetrahydro-1H,5H-dipyrolo[3,4-b;3′,4′-e]pyrazine], two 1,2,3,5,6,7-hexa­hydro-2,4,6,8-tetra­aza-s-indacene derivatives, are both centrosymmetric and have similar S-shaped structures. In the former, there are two independent mol­ecules (A and B), both of which possess Ci symmetry. These two mol­ecules are arranged such that the benzene ring substituent of mol­ecule B is directed towards the plane of the benzene ring substituent of mol­ecule A, with a dihedral angle of 55.4 (2)° between their planes. The shortest C—H...C distance is, however, only 3.21 (1) Å. In both compounds, the benzene ring substituents are almost perpendicular to the plane of the central pyrazine ring, and the pyrrolidine rings have perfect envelope conformations. In the crystal structures of both compounds, the mol­ecules pack in a herring-bone arrangement.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104009485/fr1478sup1.cif
Contains datablocks global, I, II

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104009485/fr1478Isup2.hkl
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104009485/fr1478IIsup3.hkl
Contains datablock II

CCDC references: 245922; 245923

Comment top

During attempts to prepare 1,2,3,5,6,7-hexahydro-2,4,6,8-tetraaza-s-indacene, the title compounds, (I) and (II) were synthesized by the reaction of 2,3,5,6-tetrakis(bromomethyl)pyrazine (Ferrigo et al., 1994) with the corresponding amines. Attempts were then made to deprotect the diamines, but with little success so far.

Compound (I), with bis-benzyl substituents, crystallized with two independent centrosymmetric molecules (A and B) per unit cell. The molecular structure of (I) is illustrated in Fig. 1, and selected geometric parameters are given in Table 1. The bond distances and angles are normal, when compared with values found for similar molecules in the Cambridge Structural Database (Allen, 2002).

The molecules have an S-shape, the plane of the benzene rings being almost perpendicular to the plane of the pyrazine ring. In molecule A, the dihedral angle between the C6–C11 plane and the pyrazine ring involving atom N1 is 88.2 (2)°. In molecule B, the dihedral angle involving the C26–C31 benzene ring and the pyrazine ring involving atom N21 is 88.9 (2)°. The pyrrolidine rings have perfect envelope conformations, with atoms N2 and N22 at the flaps. The two Csp3 atoms (C3 and C4a in molecule A, and C23 and C24 in molecule B; see Fig. 1) lie in the plane of the pyrazine ring. The Cremer & Pople (1975) puckering parameters Q(2) and ϕ(2) are 0.289 (3) Å and 1.9 (6)° for molecule A (atom N2), and 0.290 (3) Å and 182.1 (7)° for molecule B (atom N22).

The two molecules are arranged such that the benzene ring of molecule B (C26–C31) is directed towards the plane of the benzene ring of molecule A (C6–C11), as shown in Fig. 1. These rings are inclined to one another by 55.4 (2)°. The shortest C—H···C distance, C29—H29A···C9, is, however, only 3.21 (1) Å for H29···C9.

In the crystal, the molecules stack along the c axis, with molecules A and B in separate columns. The molecules are arranged head-to-head (or tail-to-tail) in a herringbone arrangement, as shown in Fig. 2. There are no short intermolecular contacts (< 3.2 Å) in the crystal structure, apart from the arrangement noted above.

Compound (II), with bis-methoxybenzyl substituents, also possesses Ci symmetry. The molecular structure of (II) is illustrated in Fig. 3, and selected geometric parameters are given in Table 2. The overall structure is similar to that of (I) and, again, the bond distances and angles are normal (Allen, 2002). The molecule has an S-shape (Fig. 3), the plane of the benzene ring being inclined to the plane of the pyrazine ring by 86.6 (1)°. The pyrrolidine rings have perfect envelope conformations, with atom N2 at the flap. The two Csp3 atoms (C3 and C4) lie in the plane of the pyrazine ring. The Cremer & Pople (1975) puckering parameters Q(2) and ϕ(2) are 0.288 (1) Å and 178.2 (3)°. The methoxy substituent on the benzene ring lies in the plane of the ring, with a C12—O1—C9—C10 torsion angle of −179.85 (13)°.

In the crystal of (II), the molecules stack along the c axis and are arranged head-to-head (or tail-to-tail) in a herringbone arrangement, as shown in Fig. 4. Again, there are no short intermolecular contacts (< 3.2 Å) in the crystal structure.

Experimental top

Compounds (I) and (II) were prepared by the reaction of 2,3,4,5-tetrakis(bromomethyl)pyrazine (Ferrigo et al., 1994) with benzylamine (for I) or 4-methoxybenzylamine (for II), both in dry methanol. Crystals suitable for X-ray analysis were obtained by slow evaporation of solutions of pure (I) and (II) in CHCl3, after about 1 week.

Refinement top

For both (I) and (II), H atoms were included in calculated positions and treated as riding atoms, to ensure as high a parameters/reflections ratio as possible [C—Haromatic = 0.95 Å and C—HCH2 = 0.99 Å, with Uiso(H) = 1.2Ueq(C), and C—HCH3 = 0.98 Å, with Uiso(H) = 1.5Ueq(C)].

Computing details top

For both compounds, data collection: EXPOSE (Stoe & Cie, 2000); cell refinement: CELL (Stoe & Cie, 2000); data reduction: INTEGRATE (Stoe & Cie, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. A view of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) 1 − x, 2 − y, −z; (ii) −x, 1 − y, −z.]
[Figure 2] Fig. 2. The molecular packing of (I), viewed down the b axis. The A molecules are centered about x = 0.5.
[Figure 3] Fig. 3. A view of (II), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) −x, 1 − y, 1 − z.]
[Figure 4] Fig. 4. The molecular packing of (II), viewed down the b axis.
(I) N,N'-di-N-benzylbispyrrolidino[3,4–5,6]pyrazine top
Crystal data top
C22H22N4F(000) = 728
Mr = 342.44Dx = 1.264 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ybcCell parameters from 5182 reflections
a = 36.228 (3) Åθ = 2.3–26.0°
b = 5.5729 (6) ŵ = 0.08 mm1
c = 8.9677 (7) ÅT = 153 K
β = 96.205 (9)°Plate, colourless
V = 1799.9 (3) Å30.40 × 0.40 × 0.10 mm
Z = 4
Data collection top
Stoe image-plate
diffractometer
1882 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.087
Graphite monochromatorθmax = 26.0°, θmin = 2.3°
Detector resolution: 0.81Å pixels mm-1h = 4444
ϕ scansk = 66
12398 measured reflectionsl = 910
3324 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.068Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.181H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0662P)2 + 1.3228P]
where P = (Fo2 + 2Fc2)/3
3324 reflections(Δ/σ)max < 0.001
235 parametersΔρmax = 0.19 e Å3
0 restraintsΔρmin = 0.18 e Å3
Crystal data top
C22H22N4V = 1799.9 (3) Å3
Mr = 342.44Z = 4
Monoclinic, P21/cMo Kα radiation
a = 36.228 (3) ŵ = 0.08 mm1
b = 5.5729 (6) ÅT = 153 K
c = 8.9677 (7) Å0.40 × 0.40 × 0.10 mm
β = 96.205 (9)°
Data collection top
Stoe image-plate
diffractometer
1882 reflections with I > 2σ(I)
12398 measured reflectionsRint = 0.087
3324 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0680 restraints
wR(F2) = 0.181H-atom parameters constrained
S = 1.02Δρmax = 0.19 e Å3
3324 reflectionsΔρmin = 0.18 e Å3
235 parameters
Special details top

Experimental. Synthesis and characterization of (I). 2,3,4,5-Tetrakis(bromomethyl)pyrazine (0.50 g, 1.10 mmol) and dried methanol (25 ml) were introduced, under an atmosphere of nitrogen, into a 100 ml two-necked flask equipped with a magnetic stirring bar and an addition funnel. Benzylamine (0.71 g, 6.63 mmol) was introduced in the additional funnel, dissolved in dried methanol (50 ml) and then added dropwise to the solution, which had been cooled to −75 °C. The mixture was stirred vigorously and the temperature allowed to increase to room temperature over a 4.5 h period. The reaction mixture was stirred for 3 d at room temperature. The yellow solution was evaporated to dryness and dichloromethane (60 ml) was added to the white residue. Filtration was carried out, the organic layer was evaporated to dryness and an orange, very sticky, solid was obtained. Two flash chromatographies on silica (l=20 cm, π=3.0 cm, m=50 g) were carried out in CH2Cl2/acetone (8:2) and a white solid was obtained. Recrystallization in hexane with a few drops of toluene gave suitable crystals for elemental analysis. Yield: 0.05 g (13%). 1H RMN (CDCl3, 400 MHz): δ=7.29–7.42 (m, 10H, H5, H6, H7), δ=4.01 (s, 8H, H2), δ=3.96 (s, 4H, H3). 13C RMN (CDCl3, 400 MHz): δ=153.85 (4 C, C1), δ=138.40 (2 C, C4), δ=129.11 (4 C, C5),δ=128.94 (4 C, C6), δ=127.81 (2 C, C7), δ=60.70 (2 C, C1), δ=57.81 (4 C, C2). ESI MS m/z: 381 ([M+K]+), 365 ([M+Na]+), 343 ([M+H]+) IR (KBR disc, cm−1): 3434(w,b), 3084(w), 3061(m), 3036(m), 3021(m), 2925(m), 2913(m), 2869(m), 2803(m), 1627(w), 1493(m), 1454(s), 1380(s), 1370(m), 1330(s), 1295(m), 1274(m), 1234(w), 1222(m), 1198(w), 1170(m), 1124(s), 1095(m), 1073(m), 1024(m), 1003(w), 982(m), 955(m), 908(w), 856(m), 823(w), 758(m), 749(s), 698(s), 641(m), 594(w), 492(w), 465(m), 407(s). M.p: 171°C (Decomp.) TLC (dichloromethane/acetone [8/2]): Rf = 0.40. Elemental analysis for C22H22N4 (Mr=342.44 g.mol−1) Calc. (%): C: 77.16 H: 6.48 N: 16.36 Found (%): C: 77.79 H: 6.17 N: 15.47

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
N10.51743 (7)0.7941 (4)0.0756 (3)0.0331 (6)
N20.42069 (7)0.8561 (5)0.1259 (3)0.0337 (6)
C10.53399 (8)0.9340 (5)0.0185 (3)0.0293 (7)
C20.48283 (8)0.8674 (5)0.0922 (3)0.0297 (7)
C30.45659 (9)0.7575 (6)0.1901 (4)0.0344 (7)
H3A0.45690.58020.18370.041*
H3B0.46250.80660.29610.041*
C40.57247 (9)0.9067 (5)0.0620 (4)0.0336 (7)
H4A0.59050.87180.02630.040*
H4B0.57370.77790.13730.040*
C50.39268 (9)0.8590 (6)0.2322 (4)0.0406 (8)
H5A0.40000.97650.31280.049*
H5B0.39140.69870.27890.049*
C60.35472 (9)0.9253 (6)0.1544 (4)0.0364 (8)
C70.33596 (10)1.1243 (6)0.1980 (4)0.0476 (9)
H7A0.34671.22170.27810.057*
C80.30114 (11)1.1832 (7)0.1246 (5)0.0570 (11)
H8A0.28831.32100.15400.068*
C90.28561 (10)1.0403 (8)0.0096 (5)0.0549 (10)
H9A0.26181.07820.03940.066*
C100.30430 (10)0.8434 (7)0.0349 (4)0.0494 (10)
H10A0.29370.74720.11600.059*
C110.33848 (9)0.7864 (6)0.0388 (4)0.0419 (8)
H11A0.35110.64800.00900.050*
N210.01705 (7)0.2962 (5)0.0652 (3)0.0362 (7)
N220.08030 (7)0.3620 (5)0.1902 (3)0.0368 (7)
C210.03425 (9)0.4333 (5)0.0443 (4)0.0340 (7)
C220.01775 (9)0.3711 (5)0.1066 (4)0.0334 (7)
C230.04457 (9)0.2660 (6)0.2267 (4)0.0375 (8)
H23A0.03910.31890.32740.045*
H23B0.04430.08840.22270.045*
C240.07269 (9)0.5967 (6)0.1174 (4)0.0370 (8)
H24A0.09020.62980.04260.044*
H24B0.07420.72810.19210.044*
C250.10884 (10)0.3692 (7)0.3173 (4)0.0440 (9)
H25A0.11120.20880.36480.053*
H25B0.10150.48470.39270.053*
C260.14594 (9)0.4430 (6)0.2682 (4)0.0404 (8)
C270.16199 (9)0.3038 (7)0.1647 (4)0.0449 (9)
H27A0.14990.16110.12740.054*
C280.19537 (11)0.3703 (7)0.1150 (5)0.0549 (10)
H28A0.20610.27430.04330.066*
C290.21316 (10)0.5770 (8)0.1698 (5)0.0542 (10)
H29A0.23600.62370.13580.065*
C300.19775 (11)0.7128 (7)0.2728 (5)0.0551 (10)
H30A0.21010.85410.31080.066*
C310.16432 (11)0.6476 (7)0.3228 (4)0.0492 (9)
H31A0.15390.74400.39510.059*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0343 (15)0.0292 (14)0.0337 (17)0.0036 (11)0.0052 (11)0.0031 (11)
N20.0321 (14)0.0355 (15)0.0330 (17)0.0019 (11)0.0015 (11)0.0041 (11)
C10.0338 (16)0.0258 (15)0.0263 (19)0.0037 (13)0.0052 (12)0.0003 (12)
C20.0325 (17)0.0289 (16)0.0258 (19)0.0028 (12)0.0058 (12)0.0010 (12)
C30.0363 (18)0.0349 (18)0.030 (2)0.0024 (13)0.0030 (13)0.0039 (13)
C40.0355 (17)0.0278 (16)0.037 (2)0.0019 (13)0.0003 (13)0.0019 (13)
C50.0395 (18)0.048 (2)0.035 (2)0.0015 (15)0.0056 (14)0.0032 (15)
C60.0351 (17)0.0416 (19)0.034 (2)0.0033 (15)0.0109 (14)0.0037 (15)
C70.050 (2)0.043 (2)0.049 (3)0.0001 (17)0.0034 (17)0.0066 (16)
C80.050 (2)0.052 (2)0.069 (3)0.0170 (19)0.009 (2)0.004 (2)
C90.039 (2)0.068 (3)0.058 (3)0.0047 (19)0.0070 (17)0.003 (2)
C100.0370 (19)0.064 (3)0.048 (3)0.0028 (17)0.0070 (16)0.0103 (18)
C110.0392 (19)0.044 (2)0.043 (2)0.0030 (15)0.0073 (15)0.0044 (16)
N210.0396 (16)0.0333 (14)0.0377 (18)0.0090 (12)0.0123 (12)0.0044 (12)
N220.0373 (15)0.0362 (15)0.0373 (18)0.0056 (12)0.0064 (12)0.0058 (12)
C210.0375 (17)0.0284 (16)0.038 (2)0.0067 (13)0.0122 (14)0.0016 (14)
C220.0374 (18)0.0314 (17)0.034 (2)0.0060 (13)0.0139 (13)0.0019 (13)
C230.0409 (19)0.0353 (18)0.038 (2)0.0051 (14)0.0128 (14)0.0060 (14)
C240.0407 (18)0.0332 (18)0.038 (2)0.0025 (14)0.0089 (14)0.0033 (14)
C250.050 (2)0.046 (2)0.035 (2)0.0079 (16)0.0050 (15)0.0022 (16)
C260.0431 (19)0.0404 (19)0.036 (2)0.0067 (15)0.0020 (14)0.0056 (15)
C270.039 (2)0.046 (2)0.048 (2)0.0096 (16)0.0003 (15)0.0002 (17)
C280.043 (2)0.065 (3)0.056 (3)0.0115 (19)0.0036 (17)0.006 (2)
C290.0332 (19)0.069 (3)0.058 (3)0.0030 (19)0.0055 (17)0.011 (2)
C300.051 (2)0.047 (2)0.065 (3)0.0032 (18)0.0049 (19)0.000 (2)
C310.056 (2)0.046 (2)0.045 (2)0.0055 (18)0.0002 (17)0.0016 (17)
Geometric parameters (Å, º) top
N1—C11.338 (4)N21—C211.343 (4)
N1—C21.342 (4)N21—C221.342 (4)
N2—C51.466 (4)N22—C251.454 (4)
N2—C31.471 (4)N22—C231.470 (4)
N2—C4i1.472 (4)N22—C241.475 (4)
C1—C2i1.395 (4)C21—C22ii1.389 (4)
C1—C41.495 (4)C21—C24ii1.483 (5)
C2—C1i1.395 (4)C22—C21ii1.389 (4)
C2—C31.493 (5)C22—C231.491 (5)
C3—H3A0.9900C23—H23A0.9900
C3—H3B0.9900C23—H23B0.9900
C4—N2i1.472 (4)C24—C21ii1.483 (5)
C4—H4A0.9900C24—H24A0.9900
C4—H4B0.9900C24—H24B0.9900
C5—C61.519 (5)C25—C261.516 (5)
C5—H5A0.9900C25—H25A0.9900
C5—H5B0.9900C25—H25B0.9900
C6—C111.375 (5)C26—C311.383 (5)
C6—C71.379 (5)C26—C271.385 (5)
C7—C81.397 (5)C27—C281.384 (5)
C7—H7A0.9500C27—H27A0.9500
C8—C91.374 (6)C28—C291.384 (6)
C8—H8A0.9500C28—H28A0.9500
C9—C101.371 (5)C29—C301.359 (6)
C9—H9A0.9500C29—H29A0.9500
C10—C111.376 (5)C30—C311.385 (6)
C10—H10A0.9500C30—H30A0.9500
C11—H11A0.9500C31—H31A0.9500
C1—N1—C2112.4 (3)C22—N21—C21111.9 (3)
C5—N2—C3113.2 (3)C25—N22—C23113.8 (3)
C5—N2—C4i113.6 (3)C25—N22—C24113.9 (3)
C3—N2—C4i108.0 (2)C23—N22—C24107.1 (2)
N1—C1—C2i124.0 (3)N21—C22—C21ii124.4 (3)
N1—C1—C4126.8 (3)N21—C22—C23126.7 (3)
C2i—C1—C4109.2 (3)C21ii—C22—C23108.9 (3)
N1—C2—C1i123.7 (3)N22—C23—C22102.5 (2)
N1—C2—C3127.0 (3)N22—C23—H23A111.3
C1i—C2—C3109.3 (3)C22—C23—H23A111.3
N2—C3—C2102.1 (2)N22—C23—H23B111.3
N2—C3—H3A111.4C22—C23—H23B111.3
C2—C3—H3A111.4H23A—C23—H23B109.2
N2—C3—H3B111.4N21—C21—C22ii123.7 (3)
C2—C3—H3B111.4N21—C21—C24ii126.8 (3)
H3A—C3—H3B109.2C22ii—C21—C24ii109.6 (3)
N2i—C4—C1102.2 (2)N22—C24—C21ii102.6 (2)
N2i—C4—H4A111.3N22—C24—H24A111.3
C1—C4—H4A111.3C21ii—C24—H24A111.3
N2i—C4—H4B111.3N22—C24—H24B111.3
C1—C4—H4B111.3C21ii—C24—H24B111.3
H4A—C4—H4B109.2H24A—C24—H24B109.2
N2—C5—C6111.1 (3)N22—C25—C26111.0 (3)
N2—C5—H5A109.4N22—C25—H25A109.4
C6—C5—H5A109.4C26—C25—H25A109.4
N2—C5—H5B109.4N22—C25—H25B109.4
C6—C5—H5B109.4C26—C25—H25B109.4
H5A—C5—H5B108.0H25A—C25—H25B108.0
C11—C6—C7118.9 (3)C31—C26—C27118.6 (3)
C11—C6—C5120.1 (3)C31—C26—C25121.9 (3)
C7—C6—C5121.0 (3)C27—C26—C25119.5 (3)
C6—C7—C8120.2 (4)C28—C27—C26120.7 (4)
C6—C7—H7A119.9C28—C27—H27A119.6
C8—C7—H7A119.9C26—C27—H27A119.6
C9—C8—C7119.5 (4)C27—C28—C29119.9 (4)
C9—C8—H8A120.2C27—C28—H28A120.1
C7—C8—H8A120.2C29—C28—H28A120.1
C10—C9—C8120.5 (4)C30—C29—C28119.7 (4)
C10—C9—H9A119.8C30—C29—H29A120.2
C8—C9—H9A119.8C28—C29—H29A120.2
C9—C10—C11119.5 (4)C29—C30—C31120.8 (4)
C9—C10—H10A120.3C29—C30—H30A119.6
C11—C10—H10A120.3C31—C30—H30A119.6
C6—C11—C10121.4 (3)C26—C31—C30120.4 (4)
C6—C11—H11A119.3C26—C31—H31A119.8
C10—C11—H11A119.3C30—C31—H31A119.8
C2—N1—C1—C2i0.5 (5)C21—N21—C22—C21ii0.0 (5)
C2—N1—C1—C4179.5 (3)C21—N21—C22—C23178.5 (3)
C1—N1—C2—C1i0.5 (5)C25—N22—C23—C22156.8 (3)
C1—N1—C2—C3178.8 (3)C24—N22—C23—C2229.9 (3)
C5—N2—C3—C2156.7 (3)N21—C22—C23—N22162.3 (3)
C4i—N2—C3—C229.9 (3)C21ii—C22—C23—N2219.1 (3)
N1—C2—C3—N2161.8 (3)C22—N21—C21—C22ii0.0 (5)
C1i—C2—C3—N218.8 (3)C22—N21—C21—C24ii179.9 (3)
N1—C1—C4—N2i163.0 (3)C25—N22—C24—C21ii156.0 (3)
C2i—C1—C4—N2i17.0 (3)C23—N22—C24—C21ii29.2 (3)
C3—N2—C5—C6171.2 (3)C23—N22—C25—C26173.6 (3)
C4i—N2—C5—C665.1 (4)C24—N22—C25—C2663.2 (4)
N2—C5—C6—C1159.6 (4)N22—C25—C26—C31119.1 (4)
N2—C5—C6—C7120.4 (4)N22—C25—C26—C2760.3 (4)
C11—C6—C7—C80.3 (6)C31—C26—C27—C281.1 (5)
C5—C6—C7—C8179.7 (3)C25—C26—C27—C28178.3 (3)
C6—C7—C8—C90.5 (6)C26—C27—C28—C290.5 (6)
C7—C8—C9—C101.1 (6)C27—C28—C29—C300.3 (6)
C8—C9—C10—C111.5 (6)C28—C29—C30—C310.4 (6)
C7—C6—C11—C100.7 (5)C27—C26—C31—C301.0 (5)
C5—C6—C11—C10179.3 (3)C25—C26—C31—C30178.4 (3)
C9—C10—C11—C61.3 (6)C29—C30—C31—C260.3 (6)
Symmetry codes: (i) x+1, y+2, z; (ii) x, y+1, z.
(II) N,N'-di-4'-methoxybenzylbispyrrolidino[2,3–5,6]pyrazine top
Crystal data top
C24H26N4O2F(000) = 428
Mr = 402.49Dx = 1.308 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3858 reflections
a = 20.852 (2) Åθ = 2.9–25.9°
b = 5.6574 (5) ŵ = 0.09 mm1
c = 8.6905 (9) ÅT = 153 K
β = 94.400 (13)°Plate, colourless
V = 1022.17 (18) Å30.50 × 0.40 × 0.10 mm
Z = 2
Data collection top
Stoe image-plate
diffractometer
1152 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.075
Graphite monochromatorθmax = 25.9°, θmin = 2.9°
Detector resolution: 0.81Å pixels mm-1h = 2525
ϕ scansk = 66
7540 measured reflectionsl = 1010
1985 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.030Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.071H-atom parameters constrained
S = 0.81 w = 1/[σ2(Fo2) + (0.0278P)2]
where P = (Fo2 + 2Fc2)/3
1985 reflections(Δ/σ)max < 0.001
137 parametersΔρmax = 0.14 e Å3
0 restraintsΔρmin = 0.13 e Å3
Crystal data top
C24H26N4O2V = 1022.17 (18) Å3
Mr = 402.49Z = 2
Monoclinic, P21/cMo Kα radiation
a = 20.852 (2) ŵ = 0.09 mm1
b = 5.6574 (5) ÅT = 153 K
c = 8.6905 (9) Å0.50 × 0.40 × 0.10 mm
β = 94.400 (13)°
Data collection top
Stoe image-plate
diffractometer
1152 reflections with I > 2σ(I)
7540 measured reflectionsRint = 0.075
1985 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0300 restraints
wR(F2) = 0.071H-atom parameters constrained
S = 0.81Δρmax = 0.14 e Å3
1985 reflectionsΔρmin = 0.13 e Å3
137 parameters
Special details top

Experimental. Synthesis and charaterization of II − 2,3,4,5-tetrakis(bromomethyl)pyrazine (1.00 g, 2.20 mmol) and dry methanol (50 ml) were introduced, under an atmosphere of nitrogen, into a 200 ml two-necked flask equipped with a magnetic stirring bar and a addition funnel. 4-Methoxybenzylamine (1.82 g, 13.26 mmol) was introduced into the addition funnel, dissolved in dried methanol (100 ml) and then added dropwise to the solution, which had been cooled to −75 °C. The mixture was stirred vigorously and the temperature allowed to increase to room temperature over 6 h and then left at this temperature for a further 16 h. The yellow solution was evaporated to dryness and dichloromethane (120 ml) was added to the white residue. Filtration was carried out and the orange filtrate was washed with water (60 ml). After separation, the organic layer was evaporated to dryness and a white slightly orange solid was obtained. A chromatographic column on silica (l=40 cm; π=4 cm; m=180 g) was carried out in dichloromethane/acetone (8/2) and then a gradient of acetone. A white slightly yellowish solid was obtained. Recrystallization in hexane and a few drops of toluene gave suitable crystals for elementaL analysis. Yield: 0.24 g (27%) 1H-RMN (CDCl3, 400 MHz): δ=7.31 (d, 4H, 3 J(5,6)=8.71 Hz, H5), δ=6.90 (d, 4H, 3 J(6,5)=8.71 Hz, H6), δ=3.98 (s, 8H, H2), δ=3.89 (s, 4H,, H3), δ=3.82 (s, 6H, H8). 13C-RMN (CDCl3, 400 MHz): δ=158.87 (2 C, C7), δ=153.40 (4 C, C1), δ=129.85 (4 C, C5), δ=129.32 (2 C, C4), δ=113.84 (4 C, C6), δ=59.59 (2 C, C3), δ=57.24 (4 C, C2), δ=55.23 (2 C, C8). ESI MS m/z: 425 ([M+Na]+), 425 ([M+Na]+). IR (KBR disc, cm−1): 3444(w,b), 3058(w), 3004(w), 2913(m), 2870(w), 2836(w), 2813(m), 2785(m), 1612(m), 1584(m), 1511(s), 1468(m), 1455(m), 1440(m), 1419(w), 1380(m), 1331(s), 1302(m), 1276(m), 1248(s), 1232(m), 1182(m), 1170(m), 1126(s), 1106(m), 1092(m), 1035(s), 1008(w), 983(w), 954(w), 928(w), 861(m), 844(w), 832(m), 823(m), 815(m), 809(s), 758(m), 765(w), 644(w), 628(m), 551(w), 515(w), 492(w), 408(m). M.p: 205°C (Decomp.) TLC (dichloromethane/acetone [8/2]): Rf = 0.30. Elemental analysis for C24H26N4O2 (Mr=402.50 g.mol−1) Calc. (%): C: 71.62 H: 6.51 N: 13.92 Found (%): C: 71.35 H: 6.13 N: 12.94

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
N10.02874 (6)0.29821 (19)0.43075 (13)0.0303 (3)
N20.13998 (5)0.63200 (19)0.68317 (13)0.0312 (3)
O10.43397 (5)0.43264 (18)0.59316 (13)0.0441 (3)
C10.03123 (7)0.3734 (2)0.39221 (15)0.0279 (3)
C20.05918 (7)0.4316 (2)0.54078 (16)0.0279 (3)
C30.12628 (7)0.4008 (2)0.61036 (17)0.0333 (3)
H3A0.12890.27200.68780.040*
H3B0.15630.36660.53040.040*
C40.07825 (7)0.7301 (2)0.72641 (16)0.0322 (3)
H4A0.07820.90490.72120.039*
H4B0.06900.68000.83160.039*
C50.18961 (7)0.6244 (3)0.81087 (17)0.0369 (4)
H5A0.17790.50430.88670.044*
H5B0.19190.77980.86330.044*
C60.25449 (7)0.5652 (2)0.75635 (16)0.0324 (3)
C70.28904 (7)0.3675 (3)0.80777 (17)0.0381 (4)
H7A0.27110.26430.87940.046*
C80.34930 (7)0.3159 (3)0.75735 (18)0.0395 (4)
H8A0.37230.18020.79490.047*
C90.37524 (7)0.4645 (3)0.65193 (17)0.0343 (4)
C100.34126 (7)0.6627 (3)0.59863 (18)0.0367 (4)
H10A0.35880.76440.52570.044*
C110.28208 (7)0.7123 (3)0.65137 (17)0.0354 (4)
H11A0.25960.85000.61530.043*
C120.47052 (8)0.2309 (3)0.6444 (2)0.0540 (5)
H12C0.51190.23170.59780.065*
H12B0.44680.08690.61360.065*
H12A0.47810.23530.75700.065*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0372 (7)0.0251 (6)0.0303 (6)0.0048 (5)0.0142 (5)0.0035 (5)
N20.0354 (7)0.0283 (6)0.0309 (7)0.0031 (5)0.0089 (5)0.0059 (5)
O10.0356 (6)0.0490 (6)0.0480 (7)0.0032 (5)0.0050 (5)0.0023 (6)
C10.0368 (8)0.0226 (7)0.0263 (7)0.0046 (6)0.0152 (6)0.0016 (6)
C20.0348 (8)0.0229 (7)0.0276 (8)0.0048 (6)0.0134 (6)0.0001 (6)
C30.0414 (9)0.0253 (7)0.0347 (8)0.0028 (6)0.0121 (6)0.0034 (7)
C40.0403 (9)0.0275 (7)0.0303 (7)0.0039 (6)0.0131 (6)0.0048 (7)
C50.0445 (9)0.0373 (8)0.0296 (8)0.0036 (7)0.0067 (7)0.0021 (7)
C60.0376 (8)0.0314 (8)0.0279 (8)0.0033 (6)0.0016 (6)0.0036 (7)
C70.0487 (10)0.0338 (8)0.0326 (8)0.0031 (7)0.0075 (7)0.0034 (7)
C80.0483 (10)0.0312 (8)0.0386 (9)0.0028 (7)0.0015 (7)0.0018 (7)
C90.0314 (8)0.0372 (8)0.0341 (9)0.0020 (6)0.0008 (6)0.0044 (7)
C100.0365 (9)0.0369 (8)0.0362 (8)0.0063 (7)0.0004 (7)0.0065 (7)
C110.0371 (9)0.0323 (8)0.0362 (8)0.0007 (6)0.0010 (7)0.0031 (7)
C120.0459 (10)0.0492 (10)0.0669 (12)0.0104 (8)0.0041 (9)0.0035 (10)
Geometric parameters (Å, º) top
N1—C11.3389 (17)C5—C61.505 (2)
N1—C21.3392 (18)C5—H5A0.9900
N2—C51.4588 (18)C5—H5B0.9900
N2—C31.4716 (17)C6—C71.386 (2)
N2—C41.4764 (17)C6—C111.392 (2)
O1—C91.3744 (18)C7—C81.393 (2)
O1—C121.4247 (18)C7—H7A0.9500
C1—C2i1.3956 (18)C8—C91.384 (2)
C1—C4i1.487 (2)C8—H8A0.9500
C2—C1i1.3956 (18)C9—C101.387 (2)
C2—C31.491 (2)C10—C111.378 (2)
C3—H3A0.9900C10—H10A0.9500
C3—H3B0.9900C11—H11A0.9500
C4—C1i1.487 (2)C12—H12C0.9800
C4—H4A0.9900C12—H12B0.9800
C4—H4B0.9900C12—H12A0.9800
C1—N1—C2112.46 (11)C6—C5—H5B109.3
C5—N2—C3113.82 (11)H5A—C5—H5B107.9
C5—N2—C4113.51 (11)C7—C6—C11117.61 (14)
C3—N2—C4107.41 (10)C7—C6—C5122.39 (13)
C9—O1—C12117.36 (12)C11—C6—C5120.00 (13)
N1—C1—C2i123.97 (12)C6—C7—C8121.79 (14)
N1—C1—C4i126.99 (11)C6—C7—H7A119.1
C2i—C1—C4i109.04 (12)C8—C7—H7A119.1
N1—C2—C1i123.58 (13)C9—C8—C7119.26 (14)
N1—C2—C3127.03 (12)C9—C8—H8A120.4
C1i—C2—C3109.40 (12)C7—C8—H8A120.4
N2—C3—C2102.45 (11)O1—C9—C8124.82 (13)
N2—C3—H3A111.3O1—C9—C10115.40 (13)
C2—C3—H3A111.3C8—C9—C10119.79 (14)
N2—C3—H3B111.3C11—C10—C9120.07 (14)
C2—C3—H3B111.3C11—C10—H10A120.0
H3A—C3—H3B109.2C9—C10—H10A120.0
N2—C4—C1i102.53 (11)C10—C11—C6121.48 (14)
N2—C4—H4A111.3C10—C11—H11A119.3
C1i—C4—H4A111.3C6—C11—H11A119.3
N2—C4—H4B111.3O1—C12—H12C109.5
C1i—C4—H4B111.3O1—C12—H12B109.5
H4A—C4—H4B109.2H12C—C12—H12B109.5
N2—C5—C6111.68 (12)O1—C12—H12A109.5
N2—C5—H5A109.3H12C—C12—H12A109.5
C6—C5—H5A109.3H12B—C12—H12A109.5
N2—C5—H5B109.3
C2—N1—C1—C2i0.19 (19)N2—C5—C6—C1160.50 (18)
C2—N1—C1—C4i179.17 (12)C11—C6—C7—C80.1 (2)
C1—N1—C2—C1i0.19 (19)C5—C6—C7—C8179.44 (14)
C1—N1—C2—C3179.49 (13)C6—C7—C8—C90.6 (2)
C5—N2—C3—C2155.61 (11)C12—O1—C9—C80.3 (2)
C4—N2—C3—C229.07 (14)C12—O1—C9—C10179.85 (13)
N1—C2—C3—N2162.58 (12)C7—C8—C9—O1179.81 (14)
C1i—C2—C3—N217.14 (14)C7—C8—C9—C100.3 (2)
C5—N2—C4—C1i156.46 (11)O1—C9—C10—C11179.40 (13)
C3—N2—C4—C1i29.73 (14)C8—C9—C10—C110.5 (2)
C3—N2—C5—C666.95 (15)C9—C10—C11—C61.0 (2)
C4—N2—C5—C6169.77 (11)C7—C6—C11—C100.7 (2)
N2—C5—C6—C7119.98 (15)C5—C6—C11—C10179.72 (13)
Symmetry code: (i) x, y+1, z+1.

Experimental details

(I)(II)
Crystal data
Chemical formulaC22H22N4C24H26N4O2
Mr342.44402.49
Crystal system, space groupMonoclinic, P21/cMonoclinic, P21/c
Temperature (K)153153
a, b, c (Å)36.228 (3), 5.5729 (6), 8.9677 (7)20.852 (2), 5.6574 (5), 8.6905 (9)
β (°) 96.205 (9) 94.400 (13)
V3)1799.9 (3)1022.17 (18)
Z42
Radiation typeMo KαMo Kα
µ (mm1)0.080.09
Crystal size (mm)0.40 × 0.40 × 0.100.50 × 0.40 × 0.10
Data collection
DiffractometerStoe image-plate
diffractometer
Stoe image-plate
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
12398, 3324, 1882 7540, 1985, 1152
Rint0.0870.075
(sin θ/λ)max1)0.6180.615
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.068, 0.181, 1.02 0.030, 0.071, 0.81
No. of reflections33241985
No. of parameters235137
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.19, 0.180.14, 0.13

Computer programs: EXPOSE (Stoe & Cie, 2000), CELL (Stoe & Cie, 2000), INTEGRATE (Stoe & Cie, 2000), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), SHELXL97.

Selected geometric parameters (Å, º) for (I) top
N1—C11.338 (4)N21—C211.343 (4)
N1—C21.342 (4)N21—C221.342 (4)
N2—C51.466 (4)N22—C251.454 (4)
N2—C31.471 (4)N22—C231.470 (4)
N2—C4i1.472 (4)N22—C241.475 (4)
C1—C2i1.395 (4)C21—C22ii1.389 (4)
C1—C41.495 (4)C21—C24ii1.483 (5)
C2—C31.493 (5)C22—C231.491 (5)
C1—N1—C2112.4 (3)C22—N21—C21111.9 (3)
C5—N2—C3113.2 (3)C25—N22—C23113.8 (3)
C5—N2—C4i113.6 (3)C25—N22—C24113.9 (3)
C3—N2—C4i108.0 (2)C23—N22—C24107.1 (2)
Symmetry codes: (i) x+1, y+2, z; (ii) x, y+1, z.
Selected geometric parameters (Å, º) for (II) top
N1—C11.3389 (17)O1—C91.3744 (18)
N1—C21.3392 (18)O1—C121.4247 (18)
N2—C51.4588 (18)C1—C2i1.3956 (18)
N2—C31.4716 (17)C1—C4i1.487 (2)
N2—C41.4764 (17)C2—C31.491 (2)
C1—N1—C2112.46 (11)C3—N2—C4107.41 (10)
C5—N2—C3113.82 (11)C9—O1—C12117.36 (12)
C5—N2—C4113.51 (11)
Symmetry code: (i) x, y+1, z+1.
 

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