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Zeitschrift für Kristallographie - New Crystal Structures

Editor-in-Chief: Huppertz, Hubert

Editorial Board: Hübschle, Christian / Janka, Oliver / Lemmerer, Andreas / Reiß, Guido / Tiekink, Edward R.T.


IMPACT FACTOR 2017: 0.252

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SCImago Journal Rank (SJR) 2017: 0.141
Source Normalized Impact per Paper (SNIP) 2017: 0.201

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2197-4578
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Volume 232, Issue 2

Issues

The twinned crystal structure of (4SR)-7-benzyl-2,4,8,8-tetramethyl-7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6(2H,4H)-dione, C16H20N4O2

Nikolay T. Tzvetkov / Beate Neumann
  • Department of Chemistry, University of Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Hans-Georg Stammler
  • Department of Chemistry, University of Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2017-01-07 | DOI: https://doi.org/10.1515/ncrs-2016-0218

Abstract

C16H20N4O2, triclinic, P1̅ (no. 2), a = 9.0959(5) Å, b = 9.1993(5) Å, c = 18.5825(9) Å, α = 100.534(4)°, β = 94.120(4)°, γ = 94.752(4)°, V = 1517.44(13) Å3, Z = 4, Rgt(F) = 0.0801, wRref(F2) = 0.2371, T = 100(1) K.

This article offers supplementary material which is provided at the end of the article.

CCDC no.:: 1522183

The asymmetric unit of the title crystal structure is shown in the figure. Tables 1 and 2 contain details on crystal structure and measurement conditions and a list of the atoms including atomic coordinates and displacement parameters.

Table 1

Data collection and handling.

Table 2

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2).

Source of material

The title compound has been obtained by a regioselective N2-alkylation reaction of (4RS)-7-benzyl-4,8,8-trimethyl-7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6(2H,4H)-dione with a large excess of methyl iodide (3.0 equiv.) in anhydrous dimethylformamide (1–2 mL per 1.0 equiv. starting material) [6]. The mixture was stirred at room temperature for 72 h in the presence of sodium hydride (1.26 equiv.) as a base. The crude product was purified by column chromatography on silica gel (dichloromethane/methanol, 95:5, Rf = 0.58) followed by RP-HPLC (methanol/water, 70:30) and recrystallization from dichloromethane/petroleum ether (90:10) to give a pure product as a white solid. Clear colorless plate crystals suitable for X-ray structure analysis were obtained after final recrystallization from methanol and crystallization over a period of several days at 268–270 K (m.p. 343–344 K).

Experimantal details

Single crystals of the title compound were multiple non-merohedrically twinned. Four domains were located and integrated. Four domains were taken into account during data integration and refinement. Carbon-bound hydrogen atoms were placed in calculated positions and were included in the refinement in the riding model approximation, with Uiso(H) set to 1.2Ueq(C).

Discussion

The title compound was prepared as a part of our study of regioselective synthesis of novel drug-like small molecules comprising an imidazo[1,2,4]triazine-3,6-dione framework [6]. Numerous biologically active compounds and natural products exhibit a condensed heterobicyclic 1,2,4-triazine scaffold [7], [8], [9].

The asymmetric unit contains two independent molecules of the title compound. The crystal structure contains four symmetry equivalent molecules per unit cell, which show an antiparallel orientation in the crystal packing. The significant shorter bonds C3–N1 = 1.280(7) Å for molecule No. 1 and C19–N5 = 1.282(7) Å for molecule No. 2, respectively, indicate the localization of the double bond in the corresponding six-membered triazine-rings. A methyl group is connected to the imidazotriazine basic structure in the corresponding asymmetric centers C2 and C18 and it is cis to the benzyl substituent in the positions N4 and N8 of the respective molecule No. 1 and 2.

The main imidazotriazine core in both molecules is almost planar including followed atoms for molecule No. 1: N1, N2, N3, N4, C1, C2, C3, C4, C6, C7, C10, O1, O2, and for molecule No. 2: N5, N6, N7, N8, C17, C18, C19, C20, C22, C23, C26, O3 O4 with r.m.s. values of 0.105 Å (for molecule No. 1) and 0.136 Å (for molecule No. 2) of the deviations from the least squares planes.

The benzyl substituent forms a second planar moiety consisting of C10, C11, C12, C13, C14, C15, C16 for molecule No. 1 (r.m.s. = 0.028 Å), and C26, C27, C28, C29, C30, C31, C32 for molecule No. 2 (r.m.s. = 0.026 Å). The tilt angle between the main imidazotriazine planes and the second planar arrangement are 69.0(1)° for molecule No. 1 and 59.7(1)° for molecule No. 2. The benzyl and the imidazotriazine moiety form a bond angle of N4—C10—C11 = 114.6(4)° for molecule No. 1 and N8—C26—C27 = 115.1(4)° for molecule No. 2, respectively.

The distance between the centroid of the two imidazotriazine planes defined above is 3.982(2) Å with a dihedral angle of 22.5(1)°.

Acknowledgements

Dr. Nikolay Tzvetkov is thankful to the German Federal Ministry of Education and Research (BMBF).

References

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About the article

Received: 2016-07-14

Accepted: 2016-12-13

Published Online: 2017-01-07

Published in Print: 2017-03-01


Citation Information: Zeitschrift für Kristallographie - New Crystal Structures, Volume 232, Issue 2, Pages 231–233, ISSN (Online) 2197-4578, ISSN (Print) 1433-7266, DOI: https://doi.org/10.1515/ncrs-2016-0218.

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©2017 Nikolay T. Tzvetkov et al., published by De Gruyter.. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. BY-NC-ND 3.0

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