Chrysanthemumic acid

Chrysanthemumic acid may exist in four stereoisomers, because of the two asymmetric carbon atoms in the cyclopropane ring. The natural acid has the D-trans configuration and this has been shown to be more insecticidally active than any of the other isomers or the racemic form. Harper et al, (4,18) have synthesized, separated, and optically resolved all of the isomers of this acid. 

The detection of microgram quantities of pyrethrins, cinerins, keto alcohols, and chrysanthemum acids by paper chromatography and by application of these techniques to a study of possible metabolites enabled certain tentative conclusions that imply hydrolysis in insects of a large portion of the radioactive pyrethrins and synergists to corresponding keto alcohols and chrysanthemum acids. 

Figure 2. Infrared spectrum of methyl-trans-chrysanthemate Prepared from DL-trans-chrysanthemum acid and collected as pure ester from gas chromatograph...

For the absolute configuration of the acid moieties, that of chrysanthemic acid was elucidated by Crombie et al. [13] in 1954 and that of chrysanthemum acid was determined by Inoue et al. [14] in 1955, respectively. The absolute configuration of the alcohol moiety was found by Katsuda et al. [15] in 1958. The complete elucidation of the absolute configuration of natural pyrethrins (Fig. 6) has led to the development of new useful synthetic products based on this model. 

Allethrin, the first synthetic pyrethroid, is a compound which is the closest in structure to cinerin I. Pyrethroids developed subsequently are mostly esters of chrysanthemic acid, and cinerin II analogs, i.e., esters of chrysanthemum acid have not been industrialized. 

Thus, Katsuda [1] synthesized an allethrolone ester of chrysanthemum acid analog (allethrin II, 38, Table 4) and examined LD50 values of allethrin (11, Table 4), allethrin II (38, Table 4), and a mixture of allethrin and allethrin II against the pyrethroid-susceptible CSMA strain and the resistant Hiroyama strain of M. domestica. The test results, shown in Table 4, can be summarized as follows ... 

Table 4 Chrysanthemic acid ester (allethrin) and modified chrysanthemum acid ester (allethrin...

A large number of the most important modem insecticides are derived from cyanohydrins. Especially some esters formed from enantiopure cyanohydrins and chrysanthemum acid derivatives are known to be very potent [201]. Nowadays, the formation of 3-phenoxybenzaldehyde cyanohydrin is performed in a biocatalytic industrial process using Me HNL or 7/bHNL isolated from mbber trees (Hevea... 

One of the early determinations of vicinal coupling constants in cyclopropanes was that of the chrysanthemumic acids, trans acid (75) shown. For the ethyl esters in benzene,... 

Numerous examples of [ 2 -I- 2] photocycloaddition of five-membered oxygen-containing heterocycles to alkenes have been reported, many of which have useful synthetic applications. The regiochemistry and stereochemistry of each adduct has not always been fully established. The lactone (311) undergoes photoaddition to cyclopentene to afford the cis,anti,cis adduct (312), whereas three stereoisomeric adducts were obtained with cyclohexene. Analogous additions of substituted lactones to alkenes have been employed in the syntheses of ( )-dihydrofomannosin acetate and cyclobutane analog of chrysanthemumic acid. The photoaddition of... 

Cbrysanthemic Acid. 2y2-Dimethyl-3-<2-methyl-I -property )cyclopropa neca rboxyl ic acid ch rysan them ummo -nocarboxylic acid chrysanthemumic acid. C,0H,6O2 mol wt 168.23. C 71.39%, H 9.59%, O 19.02%. Occurs as esters in pyrethrum flowers, see Pyrethrin I and Cinerin I, also Alle-... 

For the production of the necessary chrysanthemum acid substituent , 4-chlorotoluene is chlorinated photochemically and the 4-chlorobenzyl chloride converted into the nitrile with sodium cyanide. Base-catalysed introduction of the isopropyl group and subsequent hydrolysis of the nitrile, followed by chlorination, yields 2-isopropyl-(4-chlorophenyl)-acetyl chloride as an intermediate component for the production of fenvalerate. 

Versatile procedures have been developped particularly for the latter sequence - one illustrative example, leading to a simple synthesis of cis-chrysanthemum acid, is shown in Scheme 67. ... 

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