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Two different products from the reaction of 1‐aryl‐5‐chloro‐3‐methyl‐1 H ‐pyrazole‐4‐carbaldehyde with cyclohexylamine when the aryl substituent is phenyl or pyridin‐2‐yl: hydrogen‐bonded sheets versus dimers
Author(s) -
Orrego Hernandez Jessica,
Portilla Jaime,
Cobo Justo,
Glidewell Christopher
Publication year - 2015
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/s2053229615006403
Subject(s) - cyclohexylamine , chemistry , substituent , intramolecular force , aryl , dimer , medicinal chemistry , pyrazole , hydrogen bond , nucleophile , molecule , amide , stereochemistry , organic chemistry , catalysis , alkyl
Cyclohexylamine reacts with 5‐chloro‐3‐methyl‐1‐(pyridin‐2‐yl)‐1 H ‐pyrazole‐4‐carbaldehyde to give 5‐cyclohexylamino‐3‐methyl‐1‐(pyridin‐2‐yl)‐1 H ‐pyrazole‐4‐carbaldehyde, C 16 H 20 N 4 O, (I), formed by nucleophilic substitution, but with 5‐chloro‐3‐methyl‐1‐phenyl‐1 H ‐pyrazole‐4‐carbaldehyde the product is ( Z )‐4‐[(cyclohexylamino)methylidene]‐3‐methyl‐1‐phenyl‐1 H ‐pyrazol‐5(4 H )‐one, C 17 H 21 N 3 O, (II), formed by condensation followed by hydrolysis. Compound (II) crystallizes with Z ′ = 2, and in one of the two independent molecular types the cyclohexylamine unit is disordered over two sets of atomic sites having occupancies of 0.65 (3) and 0.35 (3). The vinylogous amide portion in each compound shows evidence of electronic polarization, such that in each the O atom carries a partial negative charge and the N atom of the cyclohexylamine portion carries a partial positive charge. The molecules of (I) contain an intramolecular N—H...N hydrogen bond, and they are linked by C—H...O hydrogen bonds to form sheets. Each of the two independent molecules of (II) contains an intramolecular N—H...O hydrogen bond and each molecular type forms a centrosymmetric dimer containing one R 2 2 (4) ring and two inversion‐related S (6) rings.