acetic acid in dichloromethane byproducts: MeOH; dropwise addn. of acetic acid to a rapidly stirred soln. of Sn-complex in CH2Cl2; MeOH and solvent removal (vac.), crystn. (hexane, -45°C);

in hexane recrystn.; elem. anal.;

in tetrahydrofuran; water THF/H2O = 95:5; removal of any volatile material; elem. anal.;