4-Chloroacetoacetate methyl ester

Reduction of 4-chloroacetoacetate methyl ester usually proceeds stereo-specifically. This activity is widely distributed in yeasts, molds and bacteria,... 

Chiral (3-hydroxy esters are versatile synthons in organic synthesis specifically in the preparation of natural products [68-70]. The asymmetrical reduction of carbonyl compounds using baker s yeast has been demonstrated and reviewed [5,71,72]. In the stereoselective reduction of P-keto ester of 4-chloro- and 4-bromo-3-oxobutanoic acid, specifically 4-chloro-3-oxobutanoic acid methyl ester, Sih and Chen [73] demonstrated that the stereoselectivity of yeast-catalyzed reductions may be altered by manipulating the size of ester group using y-chloroacetoacetate as substrate. They also indicated that the e.e. of the alcohol produced depended on the concentration of the substrate used. Nakamura et al. [74] demonstrated the reduction of p-keto ester with baker s yeast and controlled... 

Aryl-4-formylsydnone 4 -phenylthiosemicarbazones 183 were treated with ethyl 2-chloroacetoacetate and 2-bromoacetophenone in buffer systems of sodium acetate and acetic acid, to produce anti-oxidants 2-[(3-arylsyd-non-4-ylmethylene)-hydrazono]-4-methyl-3-phenyl-2,3-dihydrothiazole-5-carboxylic acid ethyl esters 184 and 3,4-diphenyl-2-[(3-arylsydnon-4-ylmethylene)hydrazono]-2,3-dihydrothiazoles 185 in good yields (Scheme 71) <2004BMC4633>. 

Based on the research work of Stiles (1952), one of the most important phosphorus ester insecticides, 0,0-dimethyl-0-[(l-methyl-2-carbomethoxy)vinyl] phosphate (mevinphos, 73) was introduced in 1957 under the trade name Phosdrin . It is prepared by the Perkow reaction from trimethyl phosphite and methyl a-chloroacetoacetate. 

The ammonium formate in formic acid procedure has rendered possible the first preparation of isomeric 4,5-disubstituted oxazoles.03101 Bredereck, Gompper, and Reich101 have reported the anomalous behavior of certain long-chain a-bromo ketones a single a-bromo ketone on reaction with ammonium formate in formic acid gives a mixture of two isomeric oxazoles. Refluxing of a-bromo ketones or of a-chloro-/3-keto esters with ammonium acetate in acetic acid results in the formation of substituted 2-methyl-oxazoles.40 102 Ethyl a-chloroacetoacetate on heating with ammonium carbonate or formamide in formic acid yields 4-methyloxazole-5-carboxylic ester.40 103... 

Mevinphos (96, Phosdrin ) is prepared from methyl 3-chloroacetoacetate in reaction with trimethyl phosphite. Mevinphos (Phosdrin ) is a mixture of Z and E stereoisomers in which the Z isomer was found to be 100 times more active.54 In contrast to mevinphos, E and Z isomers of bromfenvinphos (92) and chlorfenvinphos (94) show no significant difference for a number of biological properties for insecticides.55 The less toxic Clodrin (98) is synthesized from the 1-phenylethoxy ester of 3-chloracetoacetate 97 which is used for control of ectoparasites in horses, cattle, sheep, and swine.54... 

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