Methyl trans-chrysanthemate

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

From the methanol extract of the same species, lepidozenal (231) has been isolated and its structure elucidated by comparing its H-NMR spectrum with that of the c/.s-isomer (230) and by degrading it as shown in Scheme 27 214). The geometries of the two double bonds were based on the chemicd shift of the C-10 methyl (8 15.5 ppm), in the C-NMR spectrum of (233) and those of the C-10 (8 15.5) and C-4 methyls (8 24.1) of the hydrocarbon (234). The cis and trans-orientations of the double bonds were established by NOE experiments on the original aldehyde. The absolute configuration of (231) was based on the direct comparison of (—)-ketoacid (69) and its methyl ester (70) with compounds prepared from (-f)-methyl trans-chrysanthemate (236) in three steps. The signs of the optical rotations of (69) and (70) from (231) were in agreement with those of the two compounds (69, 70) prepared from (236). 

A striking example for the preferred formation of the thermodynamically less stable cyclopropane is furnished by the homoallylie halides 37, which are cyclopro-panated with high c/s-selectivity in the presence of copper chelate 3891 The cyclopropane can easily be converted into cw-permethric acid. In contrast, the direct synthesis of permethric esters by cyclopropanation of l,l-dichloro-4-methyl-l,3-pentadiene using the same catalyst produces the frans-permethric ester (trans-39) preferentially in a similar fashion, mainly trans-chrysanthemic ester (trans-40) was obtained when starting with 2,5-dimethyl-2,4-hexadiene 92). 

The change in selectivity is not credited to the catalyst alone In general, the bulkier the alkyl residue of the diazoacetate is, the more of the m-permethric acid ester results 77). Alternatively, cyclopropanation of 2,5-dimethyl-2,4-hexadiene instead of l,l-dichloro-4-methyl-l,3-pentadiene leads to a preference for the thermodynamically favored trans-chrysanthemic add ester for most eatalyst/alkyl diazoacetate combinations77 . The reasons for these discrepandes are not yet clear, the interplay between steric, electronic and lipophilic factors is considered to determine the stereochemical outcome of an individual reaction77 . This seems to be true also for the cyclopropanation of isoprene with different combinations of alkyl diazoacetates and rhodium catalysts77 . 

Much effort this year has been expended on chrysanthemic acid syntheses. Aratani et al. have extended earlier work on asymmetric synthesis (Vol. 6, p. 21) by decomposing various alkyl diazoacetates in 2,5-dimethylhexa-2,4-diene in the presence of chiral copper complexes to yield up to 92% of rrans-chrysanthemic acid in 88% dextrorotatory enantiomeric excess. Mitra has used ozonolysis of (+)-a-pinene to obtain, stereospecifically, the bromo-ketone (104) which undergoes Favorskii rearrangement to yield the anticipated ester (105) from which (+)-trans-chrysanthemic acid is readily obtained a second paper reports another route from (+)-car-3-ene initially to methyl (—)-c/s-chrysanthemate or to (—)-dihydro-chrysanthemolactone (106), both of which are convertible into (+)-rra s-chrysan-... 

Details of the preparation of methyl (-)-cis-chrysanthemate from (+)-car-3-ene have appeared (Vol. 5, p. 15 is misleading).159 Both ( )-cis- and (+)-trans-chrysanthemic acids are again reported from (+)-car-3-ene via ozonolysis 160 this work is very similar to that reported (Vol. 5, p. 15) by Sukh Dev and illustrates the lamentable delay from receipt to publication in some journals. The decomposition of ethyl diazoacetate in 2,5-dimethylhexa-2,4-diene in the presence of the chiral copper complex (72) leads to cis- and frvms-chrysanthemic acids in 60—70% optical yield the degree of asymmetric induction is dependent upon the steric bulk of R1 and R2 in (72).161 cis-Chrysanthemic acid has also been prepared from 3,3-dimethylcyclopropene, isoprene, and 2-methylpropenylmagnesium bromide followed by treatment with carbon dioxide.162... 

BEP500 CAS 10453-86-8 HR 3 5-BENZYL-3-FURYL METHYL( )-cls,trans-CHRYSANTHEMATE... 

The selectivity of the epoxidation, in conjunction with the availability of optically active terpenes from natural sources, has resulted in the application of terpene epoxides as starting materials for the synthesis of several natural products. Both enantiomers of carvone, (10) and (ent-l0), have been used for the synthesis of methyl trans- and c/.v-chrysanthemates 15 and ent-15. i+Hsy Carvone (10) was converted into hydrochlorinated compound 13 and the methylated derivative 11, which were selectively epoxidized with alkaline hydrogen peroxide, and further converted into methyl trum-chrysanthcmate 15. The same route led from (— )-(/ )-carvone ent-10) to m-chrysanthemate ent-1543 ent-13 was converted to ( + )-a-3,4-epoxycaran-2-one 1644. 

The oldest syntheses of chrysanthemates are those starting from 2,5-dimethyl-2,4-hexadiene (238). There have been more papers on the use of rhodium or antimony to catalyze the addition of diazoacetate and chiral copper complexes to create asymmetry during the addition (see Vol. 4, p. 482, Refs. 219-222). The problem with this route is to avoid the use of diazo compounds. An old synthesis of Corey and Jautelat used the ylide addition of a sulfurane to a suitable precursor (in this case a C3 unit was added to methyl 5-methyl-2,4-hexadienoate, 239), and a recent paper gives details about the addition of ethyl dimethylsulfuranylideneacetate to 2,5-dimethyl-4-hexen-3-one (240). This led exclusively to the tran -isomer 241, from which ethyl trans-chrysanthemate (185, R = Et) was made. Other ylide additions are mentioned below. 

Phenothrin, 2,2-Di methyl-3-(2-methyt-l-projrrn-jl leyc fop ropo rt ec r boxy 1 ic acid (3-phenoxyphenyl)methyl tsur 2t2 dimethyl 3-(2-metliylpropenyl)cyclopropanecarbox pile aeid m-phenoxybenzyl ester 3 -phenoxybenzyl cu, trans-chrysanthemate S-2539 Sumithrin. mol wt... 

Phenoxybenzyl (1RS)-cis,trans-chrysanthemate 3-Phenoxybenzyl (1 RS)-cis,trans-2,2-dimethyl-3-(2-methyl-prop-1 -enyl)cyolopropanecarboxylate m-Phenoxybenzyl ( )-cis,trans-2,2-dimethyl-3-(2-methylpropenyl)-cyclopropanecarboxylate 3-... 

Chrysauthemie esters. Belgian chemists noted that chrysanthemic acid could be formed from two isopropylidene units and, indeed, they obtained /rnns-methyl chrysanthemate (2) in 60% yield by reaction of methyl trans A-oxobutenoate (1) with isopropylidenetriphenylphosphorane (—78->20°). Cyclopentylidenetriphenylphosphorane reacts with (1) in the same way, but other dialkylmethylenetriplienylphosphoranes react to form dienoic esters. 

R,3R)-l,l,2,3-Tetramethylcyclopropane (35) (note change in CIP rank) has been prepared (equation 19) from methyl (-l-)-trans-chrysanthemate (34), as has the dicarboxylic acid 33 The visible rotation for 35 was not reported, but a strong positive... 

Allyl 3-methyl butyrate. See Allyl isovalerate 1-Allyl-3,4-methylenedioxybenzene 4-Allyl-1,2-methylenedioxybenzene. See Safrol (1S)-3-Allyl-2-methyl-4-oxocyclopent-2-enyl-(1 R)-trans-chrysanthemate. See,S-Bioallethrin 3-Allyl-2-methyl-4-oxo-2-cyclopenten-1-yl chrysanthemate dl-3-Allyl-2-methyl-4-... 

Benzyl-3-furylmethyl (+)-cis-chrysanthemate (5-Benzyl-3-furyl)methyl(1R)-cis-chrysanthemate. See Cismethrin (5-Benzyl-3-furyl) methyl(1 R)-trans-chrysanthemate. See Bioresmethrin 5-Benzyl-3-furyl methyl ( )-cis,trans-... 

Synonyms trans-(+)-Allethrin d-Allethrolone d-trans-chrysanthemate d-Allethrolone chrysanthemumate d-Allethronyl d-trans-chrysanthemumate 2-Allyl-4-hydroxy-3-methyl-2-cyclopenten-1 -one (1S)-3-Allyl-2-methyl-4-oxocyclopent-2-enyl-(1R)-trans-chrysanthemate d-AllyIrethronyl d-trans-chrysanthem ate Classification Pyrethroid Empirical C19H26O3... 

Synonyms Chrysanthemum monocarboxylic acid pyrethrolone ester Cyclopropanecarboxylic acid, 2,2-dimethyl-3-(2-methylpropenyl)-, ester with 4-hydroxy-3-methyl-2-(2,4-pentadienyl)-2-cyclopenten-1-one Pyrethrolone, chrysanthemum monocarboxylic acid ester (+)-Pyrethronyl (+)-trans-chrysanthemate Classification Pyrethrins (natural)... 

OH methyl (cis, trans) chrysanthemic acid (3-OHMe CPCA)... 

Oxidation reactions occur on several sites of the acid and alcohol moieties, depending on the chemical structures. For example, the trans methyl of the isobutenyl group in chrysanthemates is preferentially oxidized over the cis methyl group in rats, and the 4 -position of the phenoxy ring is oxidized to a larger extent as compared with other positions [8] (Fig. 1). 

Trans selectivity in chrysanthemates was obtained by using a bulky copper catalyst (36) together with a sterically4iindered dia/oester (1-methyl diazoacetate), whereas cu-pyrethraies can be obtained by dehalogenation of the cti-cyclopropane resulting from cydopropanation of 2Hmethyl-5,5,5-trichlorO 2-pentene 50. ... 

ALLYL-2-METHYL-4-OXO-2-CYCLOPENTEN-1-YL CHRYSANTHEMATE see AFR250 dl-3-ALLYL-2-METHYL-4-OXOCYCLOPENT-2-ENYL dl-cis trans CHRYS-ANTHEMATE see AFR250 ALLYL MUSTARD OIL see AGJ250... 

Reported here is the synthesis and insecticidal activity of some related pyrethroids represented by general formula 2 prepared by condensing methyl phenyl substituted pyrazole methanols with the more readily available dichloro chrysanthemic acid chloride (DV-acid Chloride). All of the pyrethroid samples were also prepared and tested as approximately a 4 3 trans/cis mixture of isomers. 

In the chrysanthemic acid synthesis (Scheme 2), the ee of the product increased with the bulkiness of the R group [11]. The highest ee achieved was 70%, when R was methyl (the amino acid was alanine) and R was 2-octyloxy-5-tert-butylphe-nyl. The catalyst with the R-configuration (from D-amino acid) favored the formation of d-trans and d-cis isomers to that of l-trans and l-cis isomers, respectively. 

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