Meier, H. Chem. Ber. 1981, 114, 2938. dioxide in glacial acetic acidI2 provided the selenadiazole 11 and the pyrazolone 10 in equal proportions. After separation, 11 upon brief pryolysis and distillation gave the desired acetylene 1313 which was silylated to 14.14 Bromination of 3, 5-dimethoxybenzaldehyde and conversion to its dimethyl acetalI5 15 was followed by metal-halogen exchange with n-butyllithium at 0" C. The lithiated acetal 16, ...
