Hydrogen bonding in cyclic imides and amide carboxylic acid derivatives from the facile reaction of cis ‐cyclohexane‐1,2‐carboxylic anhydride with o ‐ and p ‐anisidine and m ‐ and p ‐aminobenzoic acids

The structures of the open‐chain amide carboxylic acid rac ‐ cis ‐2‐[(2‐methoxyphenyl)carbamoyl]cyclohexane‐1‐carboxylic acid, C 15 H 19 NO 4 , (I), and the cyclic imides rac ‐ cis ‐2‐(4‐methoxyphenyl)‐3a,4,5,6,7,7a‐hexahydroisoindole‐1,3‐dione, C 15 H 17 NO 3 , (II), chiral cis ‐3‐(1,3‐dioxo‐3a,4,5,6,7,7a‐hexahydroisoindol‐2‐yl)benzoic acid, C 15 H 15 NO 4 , (III), and rac ‐ cis ‐4‐(1,3‐dioxo‐3a,4,5,6,7,7a‐hexahydroisoindol‐2‐yl)benzoic acid monohydrate, C 15 H 15 NO 4 ·H 2 O, (IV), are reported. In the amide acid (I), the phenylcarbamoyl group is essentially planar [maximum deviation from the least‐squares plane = 0.060 (1) Å for the amide O atom] and the molecules form discrete centrosymmetric dimers through intermolecular cyclic carboxy–carboxy O—H...O hydrogen‐bonding interactions [graph‐set notation R 2 2 (8)]. The cyclic imides (II)–(IV) are conformationally similar, with comparable benzene ring rotations about the imide N—C ar bond [dihedral angles between the benzene and isoindole rings = 51.55 (7)° in (II), 59.22 (12)° in (III) and 51.99 (14)° in (IV)]. Unlike (II), in which only weak intermolecular C—H...O imide hydrogen bonding is present, the crystal packing of imides (III) and (IV) shows strong intermolecular carboxylic acid O—H...O hydrogen‐bonding associations. With (III), these involve imide O‐atom acceptors, giving one‐dimensional zigzag chains [graph‐set C (9)], while with the monohydrate (IV), the hydrogen bond involves the partially disordered water molecule which also bridges molecules through both imide and carboxy O‐atom acceptors in a cyclic R 4 4 (12) association, giving a two‐dimensional sheet structure. The structures reported here expand the structural database for compounds of this series formed from the facile reaction of cis ‐cyclohexane‐1,2‐dicarboxylic anhydride with substituted anilines, in which there is a much larger incidence of cyclic imides compared to amide carboxylic acids.