Related Experiment Video
Updated: Mar 9, 2026
Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Three tetracyclic dibenzoazepine derivatives exhibiting different molecular conformations, different patterns of
Jeferson B Mateus-Ruíz1, Lina M Acosta Quintero1, Alirio Palma1
1Laboratorio de Síntesis Orgánica, Escuela de Química, Universidad Industrial de Santander, AA 678 Bucaramanga, Colombia.
Abstract:
The biological potential of compounds of the tricyclic dibenzo[b,e]azepine system has resulted in considerable synthetic efforts to develop efficient methods for the synthesis of new derivatives of this kind. (9RS,15RS)-9-Ethyl-11-methyl-9,13b-dihydrodibenzo[c,f]thiazolo[3,2-a]azepin-3(2H)-one, C19H19NOS, (I), crystallizes as a kryptoracemate with Z' = 2 in the space group P21, with one molecule each of the (9R,15R) and (9S,15S) configurations in the asymmetric unit, while (9RS,15RS)-9-ethyl-7,12-dimethyl-9,13b-dihydrodibenzo[c,f]thiazolo[3,2-a]azepin-3(2H)-one, C20H21NOS, (II), crystallizes with Z' = 1 in the space group C2/c. Ethyl (13RS)-2-chloro-13-ethyl-4-oxo-8,13-dihydro-4H-benzo[5,6]azepino[3,2,1-ij]quinoline-5-carboxylate, C22H20ClNO3, (III), exhibits enantiomeric disorder in the space group P-1 such that the reference site is occupied by the 13R and 13S enantiomers, with occupancies of 0.900 (6) and 0.100 (6). In each of the two independent molecules in (I), the five-membered ring adopts an envelope conformation, but the corresponding ring in (II) adopts a half-chair conformation, while the six-membered ring in the major form of (III) adopts a twist-boat conformation. The conformation of the seven-membered ring in each of (I), (II) and the major form of (III) approximates to the twist-boat form. The molecules of compound (I) are linked by two C-H...O hydrogen bonds to form two independent antiparallel C(5) chains, with each type containing only one enantiomer. These chains are linked into sheets by two C-H...π(arene) hydrogen bonds, in which the two donors are both provided by the (9R,15R) enantiomer and the two acceptor arene rings form part of a molecule of (9S,15S) configuration, precluding any additional crystallographic symmetry. The molecules of compound (II) are linked by inversion-related C-H...π(arene) hydrogen bonds to form isolated cyclic centrosymmetric dimers. The molecules of compound (III) are linked into cyclic centrosymmetric dimers by C-H...O hydrogen bonds and these dimers are linked into chains by a π-π stacking interaction. Comparisons are made with some related structures.
Related Concept Videos
02:11Conformations of Cyclohexane
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
02:18Conformations of Ethane and Propane
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered...
02:02Chair Conformation of Cyclohexane
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
01:18Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group...
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
01:28Stability of Conjugated Dienes
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.