in ethanol addn. of Sn compd. to ethanol, reflux, acid or base catalysis;

in ethanol addn. of C6H8O4Sn to alcohol, suspn. mixed thoroughly, dropwise addn. of concd. HCl until C6H8O4Sn was consumed, water and alcohol removed by heating; purifn. by vac. distn.; elem. anal., mass spectroscopy;

in diethyl ether reaction of tin, CH3CH2OCOCH=CH2 and dry HCl in ethyl ether, product mixt extd. by warm CHCl3; purifn. of monoester by fractional recrystn.;