Catalysis by di-n-butyltin oxide of a tertiary ketol rearrangement: synthesis of intermediates and analogues of valine and isoleucine biosynthesis
作者:David H. G. Crout、Daniel L. Rathbone
DOI:10.1039/c39870000290
日期:——
Di-n-butyltinoxide efficiently catalyses the rearrangement of 3-hydroxy-2-oxocarboxylic acid esters into the corresponding 2-hydroxy-3-oxo-esters, in a reaction that simulates the reversible rearrangement catalysed by the enzyme reductiosomerase.
The chemistry of penicillanic acids. Part II. Some reactions of methyl penicillanate and its 6α-bromo- and 6,6-dibromo-derivatives
作者:J. Peter Clayton、John H. C. Nayler、Michael J. Pearson、Robert Southgate
DOI:10.1039/p19740000022
日期:——
The action of methyl iodide and strong anhydrous base on methyl penicillanate or its 6α-bromo-derivative leads to S-methylation and cleavage of both thiazolidine and β-lactam rings, but with methyl 6,6-dibromopenicillanate the β-lactam system remains intact. Some further reactions of the resulting (4R)-3,3-dibromo-1-(1-methoxycarbonyl-2-methylprop-1-enyl)-4-methylthioazetidin-2-one are described.