Caffeine-N-phthaloyl-β-alanine (1/1)

Abstract

The title co-crystal [systematic name: 3-(1,3-dioxoisoindolin-2-yl) propanoic acid-1,3,7-trimethyl-1H-purine-2,6(3H,7H)-dione (1/1)], C 8H10N4O2·C11H 9NO4, is the combination of 1:1 adduct of N-phthaloyl-β-alanine with caffeine. The phthalimide and purine rings in the N-phthaloyl-β-alanine and caffeine molecules are essentially planar, with r.m.s. deviations of the fitted atoms of 0.0078 and 0.0118 Å, respectively. In the crystal, the two molecules are linked via an O - H⋯N hydrogen bond involving the intact carboxylic acid (COOH) group. The crystal structure is consolidated by C - H⋯O interactions. The H atoms of a methyl group of the caffeine molecule are disordered over two sets of sites of equal occupancy.