Chlorocarboxylic acid

This reaction is general for > -chlorocarboxylic acids of these, however onlv monochloroacetic acid is readily and cheaply obtainable, and it also gives the highest yielcf of the nitrohydrocarbon. 

By application of the Hell-Volhard-Zelinskii reaction,an a-hydrogen of a carboxylic acid 1 can be replaced by bromine or chlorine to give an a-bromo-or a-chlorocarboxylic acid 2 respectively. 

An unexpected, one-step synthesis of a-chloro-P-lactones in 40-83% yield resulted when phenyl esters of a-chlorocarboxylic acids were treated under the conditions of the Darzens reaction with strong base in the presence of ketones or aldehydes <95AG(E)2028>. Previously, phenyl esters do not appear to have been used in this reaction. 

Salmi T, Paatero E and Fagerstolt K (1993a) Kinetic Model for the Synthesis of a-Chlorocarboxylic Acids, Chem Eng Sci, 48(4) 735-751. 

Similarly, interphase catalysis permits carbonylation of haloaryls and halovinyls by NaCo(CO)4 with CO in water. The reaction proceeds according to S l mechanism and leads to high enough yields of carboxylic acids. Because C r-Cl bond is inert in these conditions, the direct and selective synthesis of chlorocarboxylic acids becomes possible. Thus, l-bromo-4-chlorobenzene gives 4-chlorobenzoic acid only (Brunet et al. 1983 Scheme 7.67). 

A particularly useful synthesis of primary nitramines involves the nitration of the appropriate carbamate ester followed by ammonolysis with gaseous ammonia in diethyl ether. The ammonium salt of the nitramine precipitates in pure form and is carefully acidified to give the free nitramine. The corresponding carbamate esters are readily synthesized from the action of chlorocarboxylic acid esters on alkylamines in the presence of alkali hydroxides. 

The method described here illustrates the transformation of optically active 2-chlorocarboxylic acids, which are readily available from 2-amino acids, via 2-chloroalkan-l-ols to alkyloxiranes with inversion of configuration at the stereocenter. Thus (R)-methyloxirane is prepared from (S)-alanine, (R)-isopropyloxirane from (S)-valine, (R)-isobutyloxirane from... 

Addition of phosphoryl chloride suppressed the secondary rearrangement by complexation of the zinc salts formed in the preparation of dichloroketene. The use of phosphoryl chloride in the zinc dechlorination of a-chlorocarboxylic acid chlorides increased the yields of ketene cycloadducts.106... 

Keywords chlorocarboxylic acid, oligomerization, polymerization, polyglycolide... 

Crowded structure of these diastereoisomers limitate the scope of this resolution method to relatively small racemic a-alkoxycarboxylic acids. Furthermore, the presence of an alkoxy group in the racemate seems to be essential because its oxygen atom also coordinates to the calcium ion. Luck of such coordination hindered formation of crystalline complex when a-chlorocarboxylic acids were tested. On the other hand, a-hydroxycarboxylic acids precipitated from the reaction mixture as simple calcium salts because of their lowest solubility among the possible combinations of the components of the reaction mixtures. 

A series of acyl derivatives of the amines at various positions have been prepared, including benzoyl derivatives,carbonates, and acyl derivatives with A-acylated amino acid and with o>-chlorocarboxylic acid residues. The latter have been reduced with LiAlH4 to the corresponding alkylamino derivatives. ... 

SCHEME 10.73 Chiral a-chlorocarboxylic acids can be generated using sugar-based auxiliaries. 

Treatment of 71 with chlorocarboxylic acid chlorides in DMF at 4°C afforded the cyclized unrearranged products 72 in low yields and the corresponding open-chain intermediates 73 in high yields no rearranged products were isolated. However, when the above reactions were performed at 35°C, the rearranged products 74 were produced along with a major amount of 72. In the case of chloroacetyl chloride at 35°C, the expected unrearranged product 72 was the only product. 

Treatment with a mixture of hydrochloric and nitric acids. Esterification with diazomethane Methyl esters of a-chlorocarboxylic acids 17... 

Solvolysis of ketene thioacetals. Reaction of ketene thioacetals (2), prepared as shown, with NCS, an alcohol, and acetonitrile provides a useful route to a-chlorocarboxylic acid esters (3). NCS can be replaced by NBS with equaUy satisfactory results. ... 

Numerous other reactions of carbanions are efficiently executed in two-phase systems using concentrated aqueous NaOH and PT catalysts for deprotonation of the carbanion precursors. These conditions are particularly suitable for synthesis of oxiranes via condensation of aldehydes and ketones with carbanions of, e.g., ot-chloronitriles, sulfones, and esters of a-chlorocarboxylic acids, known as the Darzens reaction, or with sulfonium... 

Triethylamine l,2-Oxazetidin-3-ones from a-chlorocarboxylic acid dilorides and hydroxylamines... 

Synthesis of oc-chlorocarboxylic acids with addition of 2 C-atoms... 

C-Imidomethyla(ion via carbonium ions / -Imido-a-chlorocarboxylic acids... 

Urethans and N-chlorocarboxylic acid amides from carboxylic acid amides... 

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