Cyclopropanecarboxylic acid anhydride

In the following we shall focus on heterogeneous acid-base reactions. One of the best known case studies is the reaction of crystalline benzoic acid with ammonia to form 1 1 ammonium salts [19, 20]. Crystalline p-chlorobenzoic anhydride reacts with gaseous ammonia to give the corresponding amide and ammonium salt [22] a similar reaction has been investigated in the case of optically active cyclopropanecarboxylic acid crystals [23]. 

SYN CYCLOPROPANECARBOXYLIC ACID, 3-(2,2-DICHLOROETHENYL)-2,2-DIMETHYL-, CYANO(3-PHENOXYPHENYL) METHYL ESTER, MIXED WITH ACETIC ACID ANHYDRIDE, 5-((2-(2-BUTOXYETHOXY) ETHOXY) METHYL)-6-PROPYL-l,3-BENZODIOXOLE, DIMETHYLBENZENE AND 1-METHYL 2-PYRROLIDIN ONE... 

A procedure which converts carboxylic acids under very mild conditions to acid anhydrides was discovered in the reaction of 2 equiv. of acid with carbon tetrachloride in the presence of 1 equiv. of hexa-methylphosphoramide and 1 equiv. of triethylamine in THF at -70 °C (equation 26). The anhydride of cyclopropanecarboxylic acid is, for example, formed in 76% yield. The reaction can be modified in the sense that preformed chlorotrisdimethylaminophosphonium perchlorate is used as reagent. At room temperature acids arc transformed into anhydrides in very good yield according to equation (27). The latter reagent can be applied successfully to the coupling of amino acids to form peptides. 

The Curtius rearrangement has been extensively utilized for the synthesis of numerous cyclo-propylamines 4 from cyclopropanecarboxylic acids 1. The necessary acyl azides 2 are most conveniently obtained by reaction of sodium azide with the mixed anhydride of the cyclopropanecarboxylic acid and ethyl chloroformate. ... 

Phenylacetic acids have been prepared from 2,2-dichlorostyrenes by sequential hydroboration and oxidation (Cr03-H2S04) of the intermediate trialkyl borane, and benzoyl benzoic acids (8), not readily available by other routes, have been obtained" in good yield by treatment of phthalic anhydride with aryl-lithiums at — lOO C. Syntheses of some bicyclo [1,1,0] butane-l-carboxylic acids (9) and a range of cyclopropane-1-carboxylic acids [(10) and (II)] have been described. 1-Hydroxy-cyclopropanecarboxylic acids (13) have been prepared from the hydroxy-cyclobutanone derivatives (12), following bromination and hydrolysis. 

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