Caronic acid

Hydrolysis of cinenn I gives an optically active carboxylic acid (+) chrysanthemic acid Ozonolysis of (+) chrysanthemic acid followed by oxidation gives acetone and an optically active dicarboxyhc acid (—) caronic acid (C7H10O4) What is the struc ture of (—) caronic acid" Are the two carboxyl groups cis or trans to each other What does this information tell you about the structure of (+) chrysanthemic acid" ... 

Fujitani [6] separated the insecticidally active syrupy ester from pyrethrum flowers in 1909 and named the ester pyrethron. Yamamoto [7, 8] subjected the hydrolysis product of this pyrethron to ozone oxidation, and isolated Iram-caronic acid and aldehyde (1 and 2, respectively, Fig. 3). Although Yamamoto did not determine the structure of this acid, he presumed it to be pyrethron acid (Fig. 3). Eventually, the presence of a cyclopropane ring in the molecule of natural pyrethrins became clear for the first time in 1923. 

Caronic acid,or 1,1 dlmethylcyclopropane 2,3 diacid is a compound of some intesest because of... 

FIGURE 13. Combination of cyclic and catemer-type H bonding in the crystal of cw-caronic acid (64c). Stereo packing diagram. Reproduced by permission of the International Union of Crystallography from Reference 113... 

Because caronic acid is optically active, its carboxyl groups must be trans to each other. (The cis stereoisomer is an optically inactive meso form.) The structure of (+)-chrysanthemic acid must therefore be either the following or its mirror image. 

Permethric Acid from Caronic Acid hoOC COOH... 

The caronic acid prepared by Perkin in 1899 for the first time [919] is an interesting precursor for caronaldehyde or a functionally equivalent derivative thereof. Because of its attractiveness a number of proposals have been made to utilize its synthetic potential. The main problem was, how to functionalize or reduce one of the two carboxy functions selectively. For caronic acid 186 or simple derivatives thereof, the problem of selective reduction to the monoaldehyde is not yet solved in a technically feasible way. Proposals like cadmium boranate [277] may have their merits for the... 

Other routes giving access to caronic acid are shown in Reaction scheme 116. The easiest one seems to be the sulfurane addition to mesityl oxide (as shown in Reaction scheme 63) and subsequent haloform reaction [283] to give trans caronic acid 186, Thermal treatment [283] or a catalytic process in acetic anhydrid [286], yields the ds-caronic 187 anhydride as a very interesting chemical. For example, on treatment with sodium trichloroacetate in acetonitrile, it traps the trichloromethyl anion (Reaction... 

Several interesting stereochemical problems and transformations have been investigated in the caronic acid series. Only one enantiomer of racemic trans-caronic acid methylester is readily saponified at Pn 7 in the presence of porcine liver esterase, affording the semiester with 1-R-, 3-R-absolute configuration [87], leaving the 1-S-, 3-S-diester totally unreacted. The prochiral cis-caronic dimethylester is not attacked enzymatically, instead it behaves as an inhibitor of that esterase. 

Both, the racemic semiesters of trans-caronic acid and cis-caronic acid may be resolved in a classical manner by phenethylamine [296]. Afterwards, the transition from one single isomer into its functional mirror image without any epimerization of the asymmetric carbons is feasable [297], as outhned in Reaction sequence 120 which allows the transformation of all optical isomers into the economically useful one, including in an analogue manner the transisomer. 

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