2-AZABUTA-1,3-DIENE-4-CARBONITRILES - STEREOSELECTIVE SYNTHESIS AND NUCLEOPHILIC-SUBSTITUTION AT THE CARBON-NITROGEN DOUBLE-BOND

The synthesis of (E)-1-methoxy-2-azabuta-1,3-diene-4-carbonitriles was performed by methylation of N-alkenylamides 9 and 11. The Z isomers w ere obtained by treatment of methylthio-2-azabuta-1,3-diene-4,4-dicarb onitriles with sodium methoxide in methanol. We also describe the reac tions of methylthio-2-azabuta-1,3-diene-4,4-dicarbonitriles with pyrro lidine, which afforded 1-(1-pyrrolidinyl) derivatives 20, 21, and 23. X-ray crystallographic analyses of 21 and 23 established the E stereoc hemistry of the C-N double bond.