1-Substituted derivatives of 2-aryl-5-oxopyrrolidine-2-carboxylic acid.

The structures of two potential anti-human immunodeficiency virus type 1 (HIV-1) non-nucleoside reverse transcriptase inhibitors (NNRTI), namely 1-benzyl-5-oxo-2-phenylpyrrolidine-2-carboxamide, C(18)H(18)N(2)O(2), (III), and 2-(4-isopropoxyphenyl)-5-oxo-1-(4-tolyl)pyrrolidine-2-carbonitrile, C(21)H(22)N(2)O(2), (IV), have been investigated by X-ray diffraction, confirming the butterfly-like conformation of both compounds. The pyrrolidine ring is in an envelope conformation in (III) and a half-chair conformation in (IV). Two intermolecular N[bond]H...O hydrogen bonds are present in the crystal structure of (III), with N...O distances of 2.995 (2) and 2.927 (2) A.