REACTIVITY OF BENZYL DISULFIDE AND THIOLATE IONS TOWARDS ACTIVATED NITROBENZENES IN N,N-DIMETHYLACETAMIDE

Benzyl thiolate and disulfide ions readily displace the nitro group of activated nitrobenzenes XC6H4NO2 at room temperature, in the X order: 2-NO2 (1)>4-NO2 (2)>2-CN (3)>4-CN (4), 4-C(O)C6H5 (5) > 4-CO2CH3 (6) >3-NO2 (7), as shown by spectroelectrochemistry in N,N-dimethylacetami de. The addition of the nitroaromatics 1-6 to thiolate ions yields the monosulfides XC6H4SCH2C6H5, the slow formation of which is observed a t the expense of a colored sigma(-) adduct for X = 3-NO2 (7). With the strongly reducing C6H5CH2S2- ions, the unsymmetrical disulfides XC6H4 S2CH2C6H5 resulting from the SNAr NO2 displacement quantitatively evol ve to XC6H4Sx-, (x=1, 2) ions. The overall process provides an origina l pathway to these species of synthetic utility, the generation of whi ch is difficult by direct substitution of inorganic (poly)sulfide ions .