Reaction of β-Nitro Enamines with Isocyanates, Isothiocyanates and Dimethyl Acetylenedicarboxylate

Article abstract of DOI:10.1246/bcsj.59.3871

β-Nitro enamines (1) reacted with isocyanates and isothiocyanates to give β-(substituted carbamoyl) and β-(substituted thiocarbamoyl) β-nitro enamines, respectively.The reaction of 1 with benzoyl isothiocyanate gave β-(benzoylthiocarbamoyl) β-nitro enamines (8) and/or a mixture of 8 and 4(1H)-pyrimidinethione derivatives (9), which were cyclization products of 8.The isolated 8 afforded the corresponding 9 in high yields upon heating in DMF.The reaction of 1 with dimethyl acetylenedicarboxylate gave <2+2>cycloadducts (12) and/or a mixture of 12 and δ-nitro dienamino diesters (13) which were ring cleavage products of 12.Compounds 12 afforded 13 upon heating in toluene or xylene.