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
作者:Fatima Al-Omran、Rafat M. Mohareb、Adel Abou El-Khair
DOI:10.3390/molecules16076129
日期:——
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.
2-(苯并噻唑-2-基硫)乙腈(2)与呋喃-2-醛或噻吩-2-醛的Knoevenagel缩合反应独家生成E异构体4a–b,而化合物2与苯甲醛或带有施电子基团的对位取代苯甲醛的缩合反应则得到E/Z混合物4c–e,E异构体优先生成。呋喃-2-醛(3a)与1-(苯并噻唑-2'-基硫)丙-2-酮(5)或2-(2'-氧基丙基硫)-3-苯基喹唑啉-4(3H)-酮(9)的缩合反应则独家生成Z异构体6和10,分别。新合成化合物的结构通过元素分析、1H-NMR和13C-NMR谱、COSY、HSQC、HMBC、NOE、MS以及X射线晶体学研究得以阐明。