As part of a program devised to evaluate the electrical effect of the sulfur atom in various states of oxidation on contiguous groups in organic molecules we have prepared 2, 5- dicarbomethoxy-3, 4-dihydroxythiophene (I), 4 2, 5-dicarbethoxy-3, 4-dihydroxythiophene-l- oxide (11), 2, 5-dicarbethoxy-3, 4-dihydroxyethiophene-1-dioxide (111), 3, 4-dihydroxy-2, 5- diphenylthiophene-1-dioxide (IV), 2, 5-dicarbethoxy-3, 4-dihydroxy-furan (V), 6 2, 5- ...
