Preparation of 2-alkoxy-4-alkyl-5(4H)-oxazolones from mixed anhydrides of N-alkoxycarbonylamino acids.
A general procedure for the preparation of 2-alkoxy-4-alkyl-5(4H)-oxazolones (AlkOx's) from N-tert-butoxy-, N-benzyloxy- and N-(9-fluorenylmethoxy)-carbonylamino acids has been devised. Purified mixed anhydrides are prepared from the parent acid and isopropenyl chloroformate and left in chloroform (Boc) for 24 h or dimethylformamide (Z, Fmoc) for 0.5-2 h. Symmetrical anhydride that may originate from disproportionation or reaction of AlkOx with hydrolyzed product is partially removed by extracting the AlkOx into petroleum ether. The products contain 0.5-30% of symmetrical anhydride.
Benoiton
N L
NL
Department of Biochemistry, University of Ottawa, Ontario, Canada.
Chen
F M
FM
D000596:Amino Acids / Q000737:chemistry*; D000812:Anhydrides / Q000737:chemistry*; D015394:Molecular Structure; D010081:Oxazolone / Q000031:analogs & derivatives* / Q000138:chemical synthesis
D000596:Amino Acids; D000812:Anhydrides; D010081:Oxazolone