Effects of substituents on the chlorination of methyl 3‐hydroxythiophene‐2‐carboxylate and on the reaction of the resulting chlorinated products with active hydrogen containing compounds

The title tandem reactions that produce 5-substituted compounds of methyl 3-hydroxythiophene-2-carboxylate can also be applied with a minor modification to the 4-alkyl and 4-aryl derivatives thereof. On the other hand, 5-alkyl and 5-aryl derivatives that undergo a similar smooth chlorination behave in the second reaction in a different manner.