Chrysanthemum

Chrysanthemic acid (obtained from chrysanthemum flowers)... 

Pyrethrms are a group of naturally occurring insecticidal substances found in the flowers of vanous plants of the chrysanthemum family The following is the structure of a typical pyrethnn cmerin I (exclusive of stereochemistry)... 

Sodium selenate has been used on a small scale in commercial greenhouses, primarily for growing carnations and chrysanthemums. It is transformed by the plants into volatile selenides, which repel red spiders, mites, thrips, and aphids (see Insect control technology). Sodium selenite is not intended for crops which could ultimately be used as food for humans or domestic animals. 

Chrysanthemum cineraricefolium Bocc. Chrysanthemine is a mixture of choline and stachydrine (Marino-Zuco, Chem. Soc. Abstr., 1891, 60, 333 1892, 62, 84 Yoshimura and Trier, Zeit. Physiol. Chem., 1912, 77, 290). 

Chondrodendron polyanthum, 371 Chondrodendron tomentosum, 363, 371, 373, 377, 391 alkaloids, 376 Chondrodine, 363, 364 Chondrofoline, 364, 365 Chrycentrine, 172, 313 Chiysanthemine, 773 Chrysanthemum cineraricefoHum, 773 Chuchuara, 781 Chuehuhuasha, 781 Cicuta virosa, 13 Cinchamidine, 419, 429 Cinchene, 439 Cinchenine, 438, 439, 440 apoCinchenine, 440, 441 Cincholoipon, 438 Cincholoiponic acid, 438, 443 Cinchomeronic acid, 183 Cinchona alkaloid structure, synthesis, 457 Cinchona alkaloids, bactericidal action of some derivatives, 478 centres of asymmetry, 445 constitution, 435 formulae and characters of transformation products, 449, 451 general formula, 443 hydroxydihydro-bases, 448, 452-4 melting-points and specific rotations, 446... 

We ve discussed only open-chain compounds up to this point, but most organic compounds contain rings of carbon atoms. Chcysanthemic acid, for instance, whose esters occur naturally as the active insecticidal constituents of chrysanthemum flowers, contains a three-membered (cyclopropane) ring. 

Pyrethrins are esters and therefore may be discussed in terms of the chrysanthemumic or pyrethric moiety and the keto alcohol moiety. 

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. 

Chrysanthemum dicarboxylic acid or pyrethric acid may exist in eight stereoisomers, owing to the trans or cis configuration on the side chain of the double bond as well as that of the cyclopropane. The natural acid has been shown to be the trans-trans acid. As in the case of the chrysanthemum monocarboxylic acid, the naturally occurring configuration is more insecticidally active than the racemic form or any of the three isomers synthesized. 

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. 

Furethrin, furfurylrethronyl ester of chrysanthemum mono-carboxylic acid... 

Cyclethrin, 3-(2-cyclopentanyl)-2-methyl-4-oxo-2-cyclopen-tenyl chrysanthemum monocarboxylate... 

Barthrin, 6-bromopiperonyl ester of chrysanthemum monocar-boxylic acid... 

This is interesting when one considers the effect of synergists on the synthetics. All of the synthetics mentioned above are based on chrysanthemum monocarboxylic acid and in the case of allethrin, cyclethrin, and furethrin on the alcohol moiety there is only one double bond. When checked against the standard synergists, these synthetics do not show the degree of synergism shown by pyrethrins and this may be because of the fact that there is only one double bond for epoxidation, compared with two in the pyrethrolone radical, and therefore the synergist would not block this epoxidation step as effectively. 

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

Specific inhibitors have also been extracted, and studied, from Cyperns esculentus (146) Artemisia vulgaris (87) Madia glomerata (26) roots of Chrysanthemum morifolium (4) Zinnia oligantha (145) and Vitis vinifera (133). 

STAHL, for instance, was able to demonstrate that on irradiation with long-wavelength UV light the naturally occurring contact insecticides pyrethrin I and II, cinerin I and II and jasmolin I and II present in Chrysanthemum cinerariifolium are converted to inactive pyrethrin oxides by the incorporation of oxygen [7]. 

Endosulfan is a popular pesticide with greenhouse chrysanthemum producers. Surveys of usage patterns and potential exposure were conducted in Ontario (Archibald et al. 1994b). Collection and analysis of a-and P-endosulfan and endosulfan sulfate in greenhouse air have been described (Vidal et al. 1997). Results indicate that 7.5% of the initial concentration of endosulfan remained in the greenhouse atmosphere 24 hours after application. 

Archibald BA, Solomon KR, Stephenson GR. 1994b. Survey of pesticide use by Ontario greenhouse chrysanthemum producers. Bull Environ Contam Toxicol 53(4) 486-492. 

The compounds featured in Table 1.1 are considered briefly here. Pyrethrins are lipophilic esters that occur in Chrysanthemum spp. Extracts of flower heads of Chrysanthemum spp. contain six different pyrethrins and have been used for insect control (Chapter 12). Pyrethrins act upon sodium channels in a manner similar to p,p -DDT. The highly successful synthetic pyrethroid insecticides were modeled on natural pyrethrins. 

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