Reaction of oximes with dimethyl carbonate: a new entry to 3-methyl-4,5-disubstituted-4-oxazolin-2-ones
摘要:
The reaction of ketone oximes with dimethyl carbonate (DMC) carried out in an autoclave at 180-190-degrees-C and in the presence of K2CO3 yields 3-methyl-4,5-disubstituted-4-oxazolin-2-ones. The reaction can be applied to both aliphatic and aromatic ketone oximes, provided that a methylene group be present near the C=N bond. Nonoptimized yields range from 22 to 48%. The reaction seems to be a [3,3] sigmatropic rearrangement where DMC plays a key role in causing the initial N-methylation of the oximes.
Reaction of oximes with dimethyl carbonate: a new entry to 3-methyl-4,5-disubstituted-4-oxazolin-2-ones
摘要:
The reaction of ketone oximes with dimethyl carbonate (DMC) carried out in an autoclave at 180-190-degrees-C and in the presence of K2CO3 yields 3-methyl-4,5-disubstituted-4-oxazolin-2-ones. The reaction can be applied to both aliphatic and aromatic ketone oximes, provided that a methylene group be present near the C=N bond. Nonoptimized yields range from 22 to 48%. The reaction seems to be a [3,3] sigmatropic rearrangement where DMC plays a key role in causing the initial N-methylation of the oximes.
is described. N-Methyl-O-alkoxyformate hydroxylamine hydrochloride reagents can be prepd. in two high-yielding steps from N-Boc-N-methylhydroxylamine and were found to be benchstable. These were reacted with a variety of carbonyl compds. to give the corresponding α-functionalized products in 48-98% isolated yield via a proposed [3,3]-sigmatropic rearrangement.
Reaction of oximes with dimethyl carbonate: a new entry to 3-methyl-4,5-disubstituted-4-oxazolin-2-ones
作者:C. A. Marques、M. Selva、P. Tundo、F. Montanari
DOI:10.1021/jo00073a041
日期:1993.10
The reaction of ketone oximes with dimethyl carbonate (DMC) carried out in an autoclave at 180-190-degrees-C and in the presence of K2CO3 yields 3-methyl-4,5-disubstituted-4-oxazolin-2-ones. The reaction can be applied to both aliphatic and aromatic ketone oximes, provided that a methylene group be present near the C=N bond. Nonoptimized yields range from 22 to 48%. The reaction seems to be a [3,3] sigmatropic rearrangement where DMC plays a key role in causing the initial N-methylation of the oximes.