... The organic layer was evaporated to dryness under vacuum at 45 "C and the residue was dissolved in 1.3 L of methanol saturated with ammonia. ... (16) Wong, M. Y. H.; Gray, G. R. J. Am. Chem. SOC. 1978,100,3548. J. Org. Chem., Vol. 53, No. 11, 1988 2409 ...