MOLECULAR COCRYSTALS OF CARBOXYLIC-ACIDS .15. PREPARATION AND CHARACTERIZATION OF HETEROCYCLIC BASE ADDUCTS WITH A SERIES OF CARBOXYLIC-ACIDS, AND THE CRYSTAL-STRUCTURES OF THE ADDUCTS OF 2-AMINOPYRIMIDINE WITH 2,6-DIHYDROXYBENZOIC ACID, 4-AMINOBENZOIC ACID, PHENOXYACETIC ACID, (2,4-DICHLOROPHENOXY)ACETIC ACID, (3,4-DICHLOROPHENOXY)-ACETIC ACID AND SALICYLIC-ACID, AND 2-AMINOPYRIDINE WITH 2,6-DIHYDROXYBENZOIC ACID

The molecular adducts of the heterocyclic base 2-aminopyrimidine with the aromatic and aromatic aliphatic carboxylic acids salicylic acid, 2,6-dihydroxybenzoic acid and 4-aminobenzoic acid, phenoxyacetic acid, (2,4-dichlorophenoxy)acetic ar-id, and (3,4-dichlorophenoxy)acetic acid have been prepared, and their interactive modes characterized by single-crystal X-ray diffraction methods. In addition, the complexes with (4-chlorophenoxy)acetic acid, (2,3-dichlorophenoxy)acetic acid, (4-chloro-2-methylphenoxy)acetic acid and (2,4,5-trichlorophenoxy)acetic acid have been characterized by analytical methods, including infrared spectroscopy. Except for the phenoxyacetic acid adduct (2:1), all form 1:1 molecular associations in which the carboxylic acid shows a variable tendency to protonate the hetero nitrogen of the base. The 1:1 complex of 2-aminopyridine with 2,6-dihydroxybenzoic acid has also been characterized by single-crystal X-ray diffraction.