The photochemical metal‐free carboamidation of aryl radicals has been exploited for the preparation of aromatic amides, including hetero‐ and polyaromatic derivatives, under visible light irradiation of arylazo sulfones in the presence of isocyanides in aqueous acetonitrile. The process was useful for the smooth preparation of the antidepressant moclobemide.
A compound of the formula:
wherein
Ar is optionally substituted phenyl, etc. ; n is 0, 1 or 2;
R1 is hydogen atom, optionally substituted alkyl, etc. ; R2 and R3 are independently optionally substituted alkyl, etc. ;
R4 and R5 are independently hydrogen atom or optionally substituted alkyl; R6 is hydrogen atom, hydroxy or alkyl;
or a pharmaceutically acceptable salt thereof is useful as a medicament for treating retinal degenerative disorders and the like.