Unsymmetrically substituted furoxans. Part 16 [1]. Reaction of benzenesulfonyl substituted furoxans with ethanol and ethanethiol in basic medium

The use of benzenesulfonyl substituted furoxans as flexible intermediates for the synthesis of new functionalized furoxans interesting for their potential biological properties is discussed. Reaction of benzenesul-fonylphenylsulfonylfuroxan isomers 7a and 7b with ethanol and ethanethiol in basic medium affords the expected ethers and sulphides respectively. Reaction of bis(benzenesulfonyl)furoxan (1) with ethanol in basic medium gives 3-benzenesulfonyl-4-ethoxyfuroxan (2) or diethoxyfuroxan (3), according to the experimental procedure. In contrast the reaction of 1 with ethanethiol gives a mixture of substitution compounds and the 4-benzenesulfonyl-3-ethylthiofurazan (11). The structure of the compounds has been assigned by nmr spectroscopy and, in the case of 3-benzenesulfonyl-4-ethylthiofuroxan (9b), confirmed by X-ray analysis.