A Convenient Synthesis of (Z)-3- (a-Cyano-a-alkoxycarbonylmethylene)-2-piperazinones and Their Derivatives
摘要:
(Z)-3-(alpha-Cyano-alpha-alkoxycarbonylmethylene)-2-piperazinone derivatives (3) and trans-(Z)-3-(alpha-cyano-alpha-alkoxycarbonylmethylene)-octahydro-2 (1H)-quinoxalinone derivatives (5) possessing various alkoxycarbonyl groups are prepared directly from the reaction of dialkyl (E)-2,3-dicyanobutenedioates (1) with ethylenediamine (2) and with trans-1,2-diaminocyclohexane (4), respectively. Furthermore, cis-1,2-diaminocycloheptane (6) and meso-2,3-diaminobutane (8) were reacted with the diethyl ester Ib to give cis-(Z)-3-(alpha-cyano-alpha-ethoxycarbonyl-methylene)decahydro-2H-cycloheptapyrazin-2-one (7) and cis-(Z)-3-(alpha-cyanoyano-alpha-ethoxycarbonylmethylene)-5,6-dimethyl-2-piperazinone (9), respectively. The structural studies of 3, 5, 7, and 9 were carried out by NMR experiments in some details.