The synthesis and characterization of a series of cocrystals of an isoniazid derivative with butan-2-one and propan-2-one.

Four cocrystals containing N'-(butan-2-ylidene)pyridine-4-carbohydrazide (izbt) and one cocrystal containing N'-isopropylideneisonicotinohydrazide (izact) were synthesized by reacting isoniazid with either butan-2-one (for the former) or acetone (for the latter). The coformers used to synthesize the izbt cocrystals were 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2-chloro-4-nitrobenzoic acid and 1-naphthoic acid. 1-Naphthoic acid was also used with izact to form a cocrystal. The 1:1 cocrystals are: N'-(butan-2-ylidene)pyridine-4-carbohydrazide-1-naphthoic acid (izbt-1nta), C₁₀H₁₃N₃O·C₁₁H₈O₂, N'-(butan-2-ylidene)pyridine-4-carbohydrazide-2,4-dihydroxybenzoic acid (izbt-2,4-dhba), C₁₀H₁₃N₃O·C₇H₆O₄, N'-(propan-2-ylidene)pyridine-4-carbohydrazide-1-naphthoic acid (izact-1nta), C₉H₁₁N₃O·C₁₁H₈O₂, N'-(butan-2-ylidene)pyridine-4-carbohydrazide-2-chloro-4-nitrobenzoic acid (izbt-2c4n), C₁₀H₁₃N₃O·C₇H₄ClNO₄, and N'-(butan-2-ylidene)pyridine-4-carbohydrazide-2,5-dihydroxybenzoic acid (izbt-2,5-dhba), C₁₀H₁₃N₃O·C₇H₆O₄. The cocrystals containing izbt were compared to those containing the same (or similar) coformers with izact that have been reported either here or in the Cambridge Structural Database (CSD). Most of the cocrystals showed different packing despite having the same hydrogen-bonding motifs. The cocrystals were characterized by single-crystal X-ray diffraction (SC-XRD), powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC).