Bis[(2,2-dimethylpropanoyloxy)methyl] {[2-(6-amino-9H-purin-9-yl)ethoxy]methyl}phosphonate–succinic acid (2/1)

Abstract

The title compound, C20H32N5O8P·0.5C4H6O4, is composed of two 9-{2-[bis(pivaloyloxymethoxy)phosphinylmethoxy]ethyl}adenine, commonly known as adefovir dipivoxil (AD), molecules linked to the carboxylic acid groups of succinic acid (SA). The asymmetric unit contains one molecule of AD and half a molecule of SA, which sits on an inversion center. Both adenine units in the two AD molecules make AD–SA N—H...O and SA–AD O—H...N hydrogen bonds to SA. In addition, the intermolecular AD–AD N—H...O—P hydrogen bond serves to stabilize the cocrystal. There is also a π–π stacking interaction [interplanar spacing 3.34 (19) Å] between adjacent inversion-related adenine groups.