Chrysanthemic acid, structure

Chrysanthemic acid, structure of, 107 Chymotrypsin, peptide cleavage with, 1033... 

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" ... 

Figure 7 shows the course of development of various synthetic pyrethroids developed by retaining chrysanthemic acid as the acid moiety and modifying the alcohol moiety. Numerous useful compounds with favorable characteristics have been derived from the structural modification of natural cinerin I (7). These underlined compounds have been put into practical use as active ingredients, mainly for household insecticides. 

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. 

In conclusion, all of the eight stereoisomers of norchrysanthemic acid methyl esters were synthesized in stereoselective manner starting from (1/ )-inmv-chrysanthemic acid or (+)-3-carene. All stereoisomers of metofluthrin were synthesized in our laboratory. Their structure-activity relationship will be published elsewhere. 

Many semi-synthetic esters, e.g. bioresmethrin, permethrin, and phenothrin, have been produced and these have increased toxicity towards insects and also extended lifetimes. All such esters retain a high proportion of the natural chrysanthemic acid or pyrethric acid structure. 

Various structural modifications particularly involving the chrysanthemic acid moiety led to compounds with enhanced stability and insecticidal activity for a wide range of insect pests. It has been reported that plant growth was also stimulated by the photostable insecticidal biopermethrin 91, Eq. (34) [123cj. 

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. 

But chrysanthemic acid derivatives are by far not the only examples of cyclopropane-containing structures in nature. In fact, the highly strained three-membered carbocycle is virtually ubiquitous. It occurs, for example, in every green plant in the form of 1-aminocyclopropanecarboxylic acid (ACC) 2, a direct precursor to the plant hormone ethylene [3]. In addition, the cyclopropane unit is found in a variety of other natural products, inter alia in terpenes and in various cyclopropanated fatty acids [4]. The biochemical precursors of the latter are unsaturated fatty acids, and in view of the existence of polyunsaturated fatty... 

So far, we have seen situations where a proton has several neighbours, but the coupling constants to all the neighbours have been the same. What happens when coupling constants differ Chrysanthemic acid, the structural heart of the natural pyrethrin insecticides, gives an example of the simplest situation—where a proton has two different neighbours. 

Synthetic pyrethroids are a group of ester compounds having excellent insecticidal activities. After the discovery of allethrin (1), a variety of useful synthetic pyrethroids have been produced mainly by structural modification of an alcohol having an asymmetric center. The insecticidal activities greatly depend upon the stereoisomers. Therefore, much effort has been expended to develop technologies for obtaining optically active isomers. However, contrary to the case of chrysanthemic acid, chemical methods of optical resolution were not very effective for these alcohols. 

The insecticidal activity and structure-activity relationships of novel pyrethroids prepared by reacting methyl phenyl substituted pyrazole methanols with dichloro chrysanthemic acid chloride are reported. These pyrethroids are active on tobacco budworm, fall armyworm, southern corn rootworm, and aster leafhopper, generally in the concentration range of 1000-250 ppm. Although less active than the pyrethroid standard bifenthrin, the overall structure-activity of these pyrazole pyrethroids with regard to substitution patterns is similar to that previously observed with bifenthrin analogs. 

A more marked departure from the pyrethrin structure was represented by esters of chrysanthemic acid formed with substituted benzyl alcohols, such as... 

Based on former experimental findings, it was believed that the cyclopropanecar-boxylic acid structure of chrysanthemic acid is an indispensable condition of activity. A complete break with this assumption has been effected by the Japanese researchers Ohno and co-workers (1974a,b), who demonstrated that the cyclopro-panecarboxylic acid can be exchanged for 2-phenylalkanoic acids. Comparison of the absolute configuration of (1/ , 3R)-( + )-chrysanthemic acid (36) with that of... 

Punja et al. (1973) prepared several new esters of chrysanthemic acid, combining structural features of the pyrethroids with those of juvenile hormones. Of these, the JH effect of the most potent derivatives, 57,58 and 59, was nearly the same as that of the natural juvenile hormones. 

The copper-catalyzed cyclopropanation of alkenes with diazoalkanes is a particularly important synthetic reaction (277). The reaction of styrene and ethyl diazoacetate catalyzed by bis[/V-(7 )- or (5)-a-phenyl-ethylsalicylaldiminato]Cu(II), reported in 1966, gives the cyclopropane adducts in less than 10% ee and was the first example of transition metal-catalyzed enantioselective reaction of prochiral compounds in homogeneous phase (Scheme 90) (272). Later systematic screening of the chiral Schiff base-Cu catalysts resulted in the innovative synthesis of a series of important cyclopropane derivatives such as chrysanthemic acid, which was produced in greater than 90% ee (Scheme 90) (273). The catalyst precursor has a dimeric Cu(II) structure, but the actual catalyst is in the Cu(I) oxidation state (274). (S)-2,2-Dimethylcyclopropanecar-boxylic acid thus formed is now used for commercial synthesis of ci-lastatin, an excellent inhibitor of dehydropeptidase-I that increases the in vivo stability of the caibapenem antibiotic imipenem (Sumitomo Chemical Co. and Merck Sharp Dohme Co.). Attempted enantioselective cyclopropanation using 1,1-diphenylethylene and ethyl diazoacetate has met with limited success (211b). A related Schiff base ligand achieved the best result, 66% optical yield, in the reaction of 1,1-diphenylethylene and ethyl diazoacetate (275). 

Pyrethrins, Active insecticidal constituents of pyrethrum flowers. Isoln Staudinger, Ruzicka, Heh. Chim. Acta 7, 177 (1924). Prepn by reconstitution from pyrethro-lone and chrysanthemic acid Elliott, Janes, Chem. A Ind. (London) 1969, 270. Structure CrOmbie et al. J. Chem. Soc. 1956, 3963 Godin et al, ibid. [Pg.1266]

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