YPHOSPHORYLMETHYL)-5-METHYL-4,5-DIHYDRO-3H-PYRROLE N-OXIDE - SYNTHESIS AND EVALUATION OF SPIN-TRAPPING PROPERTIES

A new spin trap, the yphosphorylmethyl)-5-methyl-4,5-dihydro-3H-pyrrol e N-oxide (3), is prepared through a four-step synthetic route, The in vitro spin trapping properties of 3 have been investigated and the hy droxyl and superoxide spin adducts characterised, The persistence of t he superoxide spin adduct obtained with 3 is compared with those of th e analogues obtained with DEPMPO iethoxyphosphoryl)-5-methyl-4,5-dihyd ro-3H-pyrrole N-oxide] and DMPO in both phosphate buffer and pyridine. In 0.1 M phosphate buffer at pH 7.0, the HOO-3(.) adduct is found to be 2.8 times more persistent than HOO-DMPO., but 5.7 times less than H OO-DEPMPO., In phosphate buffer, HOO-3(.) decomposes to give HO-3(.). The stereoselectivity of the addition of free radicals on 3 is general ly poor, and mixtures of diastereomers have been observed by EPR, The overall spin trapping behaviour of nitrone 3 is more similar to that o f DMPO than that of DEPMPO.