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Similar molecular constitutions but different conformations and different supramolecular assemblies in two related fused tetracyclic benzo[ b ]pyrimido[5,4‐ f ]azepine derivatives
Author(s) -
Acosta Quintero Lina M.,
Burgos Isidro,
Palma Alirio,
Cobo Justo,
Glidewell Christopher
Publication year - 2016
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229615023876
Subject(s) - azepine , chemistry , ring (chemistry) , quinoline , indole test , stereochemistry , substituent , hydrogen bond , pyrimidine , molecule , stacking , pyridine , supramolecular chemistry , crystallography , crystal structure , medicinal chemistry , organic chemistry
A simple and effective two‐step approach to tricyclic pyrimidine‐fused benzazepines has been adapted to give the tetracyclic analogues. In ( RS )‐8‐chloro‐6‐methyl‐1,2,6,7‐tetrahydropyrimido[5′,4′:6,7]azepino[3,2,1‐ hi ]indole, C 15 H 14 ClN 3 , (I), the five‐membered ring adopts an envelope conformation, as does the reduced pyridine ring in ( RS )‐9‐chloro‐7‐methyl‐2,3,7,8‐tetrahydro‐1 H ‐pyrimido[5′,4′:6,7]azepino[3,2,1‐ ij ]quinoline, C 16 H 16 ClN 3 , (II). However, the seven‐membered rings in (I) and (II) adopt very different conformations, with the result that the methyl substituent occupies a quasi‐axial site in (I) but a quasi‐equatorial site in (II). The molecules of (I) are linked by C—H...N hydrogen bonds to form C (5) chains and inversion‐related pairs of chains are linked by a π–π stacking interaction. A combination of a C—H...π hydrogen bond and two C—Cl...π interactions links the molecules of (II) into complex sheets. Comparisons are made with some similar fused heterocyclic compounds.