[S:1]1(=[O:12])(=[O:11])[C:5]2[CH:6]=[CH:7][C:8]([NH2:10])=[CH:9][C:4]=2[CH2:3][CH2:2]1.[C:13]([C:15](=[CH:21]OCC)[C:16]([O:18][CH2:19][CH3:20])=[O:17])#[N:14].C(OCC)(=O)C>C(O)C>[C:13]([C:15](=[CH:21][NH:10][C:8]1[CH:7]=[CH:6][C:5]2[S:1](=[O:11])(=[O:12])[CH2:2][CH2:3][C:4]=2[CH:9]=1)[C:16]([O:18][CH2:19][CH3:20])=[O:17])#[N:14]5 g (27.3 mmol) of 2,3-dihydro-1-benzothiophen-5-amine 1,1-dioxide were suspended in 50 ml of ethanol under argon, 4.62 g (1 eq, 27.3 mmol) of ethyl 2-cyano-3-ethoxyacrylate were added, and the mixture was heated under reflux overnight. For working up, ethyl acetate was added to the mixture, and the precipitate which formed was filtered off with suction on a frit. The solid was dried in vacuo at 50° C. for 1.5 h. 6.87 g (81%) of the target compound were isolated and were employed without further purification in the next stage.
Loading…
