Roger Ketcham

Synthesis of Unsymmetrically Substituted Hexahydroimidazo [4,5-d] Imidazole-2,5-diones and Elucidation of Reaction Pathways

Abstract We have reported the synthesis and structural elucidation of a series of hexahydroimidazo [4,5-d] imidazole-2,5-diones and hydantoins from glyoxal and substituted ureas.1,2 The general equation of this condensation reaction and a few representative compounds: those reported, current and hypothetical, are depicted in Scheme 1.

The Reaction of Cyanothioformamide with Isocyanates − Formation of a Disulfide by Reduction of a Thiocarbonyl Group

The reactions of the title compounds are governed by sulfur redox chemistry. Thus, cyanothioformamide 2 reacts with aryl isocyanates 3a−c to give bis[3-aryl-1-(arylcarbamoyl)-2-oxo-4-(arylcarbamoylimino)imidazolidin-5-yl] disulfides 6, as shown by an X-ray crystallographic investigation of product 6a. Reaction with methyl isocyanate (3d) gives the related trisulfide 7d along with disulfide 6d. A desulfurized product, imidazolinone 10, could also be isolated from the methyl isocyanate reaction and was characterized by X-ray diffraction analysis. In boiling ethanol, 6a and 7d undergo reductive desulfurization to give 4-iminoimidazolidin-2-one 11a and the methyl analog 11d, respectively.

Reaction of a 2-iminothione with dimethyl acetylenedicarboxylate to give a pyridine derivative

Reactions of 5-imino-1,3-diphenyl-4-thioxoimidazolidin-2-one (1) and 5-imino-3-phenyl-4-(N-phenylimino)-thiazolidine-2-thione (6) provide 5,7-dihydro-2,3,4-tris(methoxycarbonyl)-5,7-diphenyl-6H-imidazo[4,5-b]-pyridin-6-one (3) and 6,7-dihydro-2,3,4-tris(methoxycarbonyl)-7-phenylthiazolo[4,5-b]pyridine-6-thione (7), respectively, when heated with dimethyl acetylenedicarboxylate.