Isobutylmalonic ester

Butabarbital Butabarbital, 5-ethyl-5-isobutylbarbituric acid (4.1.11), is also synthesized in an analogous manner by condensation of a-ethyl-a-isobutylmalonic ester with urea [9]. 

This is a general method for preparing a-bromo acids. By using exactly analogous directions -bromo- -caproic acid may be obtained in 65-70 per cent yields from w-butylmalonic ester a-bromo-isocaproic acid in 65-70 per cent yields from isobutylmalonic ester and a-bromo-/3-methyl valeric acid in 75-80 per cent yields from sec.-butylmalonic ester. 

Prepared in 55% yield by Fisdier and Sehmits (306) from malonic ester through the intermediates, isobutylmalonic ester and isobutylbromomalonio add. The latter substances were prepared essentially by the methods of Quthieit (300) and BischoS (101). 

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