The S-nitrosothiols 2-acetamido-2-deoxy-S-nitroso-1-thio-beta-D-glucopyrano
se 3,4,6-triacetate (GPSNO) and S-nitroso-N-carbamyl-D,L-penicillamine (SNC
P) were synthesized by S-nitrosation of the corresponding thiols, isolated,
and fully characterized. The nitrosothiol (TGSNO) from 1-thioglycerol was
obtained as a red gelatinous liquid, which decomposed rapidly at room tempe
rature and so was not characterized. The kinetics of decomposition of GPSNO
showed that there is a surprisingly large thermal pathway overlaid with a
Cu2+/RS- catalyzed reaction. The results strongly suggest that the product
disulfide complexes Cu2+ (for which there is some spectral evidence), leadi
ng to incomplete conversion by that route. Ascorbate also acts as a Cu2+ re
ductant. Another S-nitroso sugar, S-nitroso-1-thio-beta-D-glucose (SNTG), b
ehaved very similarly from solutions generated and used in situ. The decomp
osition of TGSNO shows induction periods suggesting that slow initial gener
ation of Cu+ (the true catalyst) is taking place. There appears to be also
a significant alternative pathway (analogous to that found for GPSNO), wher
e the rate appears to be independent of [Cu2+], but very unusually this pat
hway is effectively halted by addition of EDTA either at the start of the r
eaction or at a later time. Reaction schemes are put forward to account for
these unusual reaction characteristics.