Methylxanthines. II. Anhydrous Theobromine

Clear crystals of anhydrous theobromine (3,7-dihydro-3,7-dimethyl-1H-purine-2,6-dione, C₇H₈N₄O₂) were grown by vacuum sublimation and the X-ray structure determined. The melting point of anhydrous theobromine has been determined as 620 (1) K. Two molecules in the asymmetric unit form a pseudo- centrosymmetric dimer and pack to form a layered structure of two-dimensional hydrogen-bonded networks.

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