One-Pot Multistep Bohlmann−Rahtz Heteroannulation Reactions: Synthesis of Dimethyl Sulfomycinamate
摘要:
The synthesis of dimethyl sulfomycinamate, the acidic methanolysis product of the sulfomycin family of thiopeptide antibiotics, from methyl 2-oxo-4-(trimethylsilyl)but-3-ynoate is achieved in a 2,3,6-trisubstituted pyridine synthesis that proceeds with total regiocontrol in 13 steps by the Bohlmann-Rahtz heteroannulation of a 1-(oxazol-4-yl)enamine or in 12 steps and 9% yield by three-component cyclocondensation with N-[3-oxo-3-(oxazol-4-yl)propanoyl]serine and ammonia in ethanol.
Dimethyl sulfomycinamate, the oxazole-thiazole-pyridine product generated in the methanolysis of the thiopeptide antibiotic sulfomycin 1, is prepared in 13 steps and 8% overall yield by the Bohlmann-Rahtz heteroannulation of 1-(oxazol-4-yl)enamines and methyl 4-(trimethylsilyl)2-oxobut-3-ynoate.
A new mild method for the one-pot synthesis of pyridines
作者:Xin Xiong、Mark C Bagley、Krishna Chapaneri
DOI:10.1016/j.tetlet.2004.06.061
日期:2004.8
Polysubstituted pyridines are prepared in good yield and with total regiocontrol by the one-pot reaction of an alkynone, 1,3-dicarbonyl compound and ammonium acetate in alcoholic solvents. This new three-component heteroannulation reaction proceeds under mild conditions in the absence of an additional acid catalyst and has been used in the synthesis of dimethyl sulfomycinamate, the acidic methanolysis