4-Substituted 3-amino-2-cyanothiophenes

A one-pot synthesis of 4-substituted 3-amino-2-cyanothiophenes involving o-ethyl thioformate was reported (140L2522). The thiophene core in these 4-subsitututed 2-cyanothiophenes can be readily incorporated into more elaborate pharmaceutically relevant structures as... 

A procedure was developed (1988JPR585, 1991JPR229, 1993JCR(S)302, 1993MI1) for the synthesis of thienopyrimidinedithiones 28 involving thermal recyclization of thiazines 29, which, in turn, are prepared by the reactions of substituted 2-amino-3-cyanothiophenes 30 with carbon disulfide in the presence of bases. 

A very promising new route to substituted thiophens has recently been developed by Hartmann. The reaction of 2-aryl-1,3-oxathiolium salts such as (33) with malononitrile in the presence of base yields 3-amino-4-cyanothiophens (34), with ethyl malonate or ethyl cyanoacetate 3-hydroxy-thiophens (34a), and finally with nitromethane 3-nitrothiophens (34b). The... 

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