Synthesis and E/Z Configuration Determination of Novel Derivatives of 3-Aryl-2-(benzothiazol-2-ylthio) Acrylonitrile 3-(Benzothiazol-2-ylthio)-4-(furan-2-yl)-3-buten-2-one and 2-(1-(Furan-2-yl)-3-oxobut-1-en-2-ylthio)-3-phenylquinazolin-4(3H)-one

摘要

Knoevenagel condensation of 2-(benzothiazol-2-ylthio) acetonitrile (>2) with either furan-2-carbaldehyde or thiophene-2-carbaldehydes leads to E-isomers >4a–b exclusively, while the condensation of the compound >2 with benzaldehyde or para-substituted benzaldehydes with an electron-donating group afforded E/Z mixtures >4c–e with preferentially formation of the E-isomer. Condensation of furan-2-carbaldehyde (>3a) with either 1-(benzothiazol-2'-ylthio) propan-2-one (>5) or 2-(2'-oxo propylthio)-3-phenyl-quinazolin-4(3H)-one (>9) leads exclusively to the Z-isomers of >6 and >10, respectively. The structures of the newly synthesized compounds were elucidated by elemental analyses, ¹H-NMR and ¹³C-NMR spectra, COSY, HSQC, HMBC, NOE, MS and X-ray crystallographic investigations.