Methyl 3-cyclohexene-1 -carboxylate

Benzene-sensitized photolysis of methyl 3-cyclohexene-1-carboxylate in acetic acid leads to addition of acetic acid to the double bond. Only the trans adducts are formed. What factor(s) is (are) responsible for the reaction stereochemistry Which of the two possible addition products, A or B, do you expect to be the major product ... 

The method employed by Law, et al. to obtain Ad-disubstituted ISQs [87] was a modification of the approaches of Henbest [88], Huffman [89] and Nelson [90] (Scheme 8). Epoxidation of commercially available methyl-3-cyclohexene-1-carboxylate (80) with m-CPBA yielded a mixture of epoxides (81a and 81b), which were then opened with various amines producing the isomeric amino alcohols (82a and 82b). Only isomer 82a is capable of undergoing cyclization to the... 

Methylcyclohexene Methyl 3-cyclohexene-1-carboxylate 2-Methyl-2-cyclohexen-1-one 3-Methyl-2-cyclohexen-1-one 3-Methylcyclopentadecanone... 

Cyclohexenes and cycloheptenes containing an acyloxy group at the allylic or homoallylic positions give regiospecific addition products in polar solvents due to formation of intermediate oxonium ions of different stabilities. For example, methyl-3-cyclohexene-1-carboxylate 17 in acetic acid on benzene-sensitized irradiation gives methyl trans-4-acetoxy cyclohexane carboxylate 18 as major product along with small amount of methyl /rans-3-acetoxy cyclohexane carboxylate 19 [24]. 

Diazoacetaldehyde dimethylacetal (12) has been used as a substitute for diazoacetaldehyde in 1,3-dipolar cycloadditions with l-benzopyran-2(//)-ones (40), styrene, methyl methacrylate, 1-cyanocyclopentene, and methyl cyclohexene-1-carboxylate (41). The resulting A -pyrazolines were readily transformed in two steps into cyclopropanecarbaldehydes [e.g., 13 —> 14 (Scheme 8.4)]. In a similar manner, 3-phenylcyclopropane-l,2-dicarbaldehyde was obtained from the reaction of 12 with dimethyleneketal of cinnamic aldehyde. 

Figure 10. Synthesis of the stereoisomers of trans-6-methyl-3-cyclohexene carboxylic acid...

Substituted aromatic acids provide a route to other cyclohexyl derivatives. An example is the catalytic hydrogenation of the benzene ring in 7.107 to give 4-amino-methyl-1-cyclohexene carboxylic acid, 7.108. Partial reduction of abenzene ring... 

A highly specialized synthesis converted (-)-shikimic acid 7.169) to 7.170. Reaction with azide and catalytic hydrogenation gave 5-aminoshikimate 7.171, methyl 5-amino-3,4-dihydroxy-l-cyclohexene carboxylate) in 21% overall yield. Amino acid 7.171 is an inhibitor of EPSP synthetase, and can be used as an herbicide,... 

Tetrahydrophthalic anhydride (7.775) was converted directly to c -5-amino-3-cyclohexene carboxylic acid, 7.77 by reaction with ammonia and then NaOCl. 107.14 If 7.775 is first opened, isomerized, and converted to the trans-diester (7,775), formation of the trans-anhydride is possible (7.179). This anhydride was then converted to trons-5-amino-3-cyclohexene carboxylic acid, 7.180. A related route converted 7.175 to racemic cis-methyl 2-carboxylcyclohex-4-enoate, which was resolved with cinchonidine.lO The resolved (+) or (-)-half-esters were then converted to (-)-7.77 or (+)-7.77. 

The biotransformation of the nonsteroidal, postcoital oral contraceptive, 2-methyl-3-ethyl-4-phenyl-A -cyclohexene carboxylic acid (Vll), was examined in monkeys and rabbits. In both species, only a trace of unaltered drug was found in the urine. At least eight metabolites were separated from rabbit urine, one of which, as yet unidentified, had 1.5 to 2.0 times the estrogenic potency of the parent compound. The antifertility effect, in the rat of certain -substituted, but not of unsubstituted compounds, was not blocked by prior treatment of the animals with SKF-525A. Thus, the authors suggest that when hydrogen alone is in the para V j position, further alteration of the... 

Cyclohexene-l-carboxylic acid, 2-Kthy1, methyl ester)... 

The purity of the product was determined by the checkers by GLC analysis using the following column and conditions 3-nm by 1.8-m column, 5% free fatty acid phase (FFAP) on acid-washed chromosorb W (60-80 mesh) treated with dimethyldichlorosilane, 90 C (1 min) then 90 to 200 C (15°C per rain). The chromatogram showed a major peak for methyl 2-methyl-l-cyclohexene-l-carboxylate preceded by two minor peaks for methyl 1-cyclohexene-l-carboxylate and l-acetyl-2-methylcyclohexene. The areas of the two impurity peaks were 5-6% and 0.5-2% that of the major peak. The purity of the product seems to depend upon careful temperature control during the reaction. The total amount of the two impurities was 14-21% in runs conducted at about -15 to -20°C or at temperatures below -23°C. 

This procedure illustrates a new method for the preparation of 6-alkyl-a,g-unsaturated esters by coupling lithium dialkylcuprates with enol phosphates of g-keto esters. The procedure for the preparation of methyl 2-oxocyclohexanecarboxylate described in Part A Is based on one reported by Ruest, Blouin, and Deslongcharaps. Methyl 2-methyl-l-cyc1ohexene-l-carboxylate has been prepared by esterification of the corresponding acid with dlazomethane - and by reaction of methyl 2-chloro-l-cyclohexene-l-carboxyl ate with lithium dimethylcuprate. -... 

If the hydroxy-acid is heated with hydrobromic acid, it is converted into l-methyl-l-bromocyclohexane-4-carboxylic acid, and this is decomposed by boiling with sodium carbonate with loss of hydrogen bromide and with formation of 1-methyl-A cyclohexene-4-carboxyhc acid—... 

Diazomethane is also decomposed by N O)40 -43 and Pd(0) complexes43 . Electron-poor alkenes such as methyl acrylate are cyclopropanated efficiently with Ni(0) catalysts, whereas with Pd(0) yields were much lower (Scheme 1)43). Cyclopropanes derived from styrene, cyclohexene or 1-hexene were formed only in trace yields. In the uncatalyzed reaction between diazomethane and methyl acrylate, methyl 2-pyrazoline-3-carboxylate and methyl crotonate are formed competitively, but the yield of the latter can be largely reduced by adding an appropriate amount of catalyst. It has been verified that cyclopropane formation does not result from metal-catalyzed ring contraction of the 2-pyrazoline, Instead, a nickel(0)-carbene complex is assumed to be involved in the direct cyclopropanation of the olefin. The preference of such an intermediate for an electron-poor alkene is in agreement with the view that nickel carbenoids are nucleophilic 44). 

Tetrahydrobenzyl alcohol (( )3-cyclohexenene-l-methanol) and 30% aqueous hydrogen peroxide were purchased from Fluka, AG. 3-Cyclohexene-1-carboxylic acid and cis-4-cyclohexene-l,2-dicarboxylic acid were used as purchased from Lancaster Chemical Co. Methyl iodide, acetic anhydride, Oxone (potassium peroxymonosulfate), Aliquot 336 (methyl tri-n-octylammonium chloride), sodium tungstate dihydrate and N,N-dimethylaminopyridine (DMAP) were purchased from Aldrich Chemical Co. and used as received. 3,4-Epoxycyclohexylmethyl 3, 4 -epoxycyclohexane carboxylate (ERL 4221) and 4-vinylcyclohexene dioxide were used as purchased from the Union Carbide Corp. (4-n-Octyloxyphenyl)phenyliodonium hexafluoroantimonate used as a photoinitiator was prepared by a procedure described previously (4). 

Ethyl 2-methyl-4-oxo-2-cyclohexene-l-carboxylate, c7 Ethyl A -inethyl-A -phenylcarbainate, m379 Ethyl 2-methylpipicolinate, e217... 

Methyl 5-fluoro-4-(trifluoromethylsulfonyloxy)-2,3-dihydro-l-methyl-7-0X0-1//,7//-pyrido[3,2,l-iy]cinnoline-8-carboxylate(68,R = Me,R = R = H, R = F, R = Me, R = CF3SO2O) was reacted with 3-tributylstannyl-2-cyclohexen-l-one in the presence of lithium chloride and bis(triphenyl-phosphine)palladium(II) chloride in tetrahydrofuran for 3 days to give a 4-(3-oxo-l-cyclohexen-l-yl)derivative (92EUP470578). 

Ethyl mercaptan, e20 Ethyl 3-methylcrotonate, el 21 Ethyl methyl ketone, b393 Ethyl 1-methylnipecotate, el 77 Ethyl 2-methyl-4-oxo-2-cyclohexene-1 carboxylate, c9... 

N1 - 3-CYCLOHEXENE-l-CARBOXYLIC ACID 5-ETHYL-4-(p-HYDROXYPHENYLI-6-METHYL- ACETATE Ust r>... 

Uses The alicyclic hydrocarbons have numerous industrial applications. Cyclopropane (C3H6) is used as an anesthetic. Cyclohexane (CgH ) is used as a chemical intermediate as an organic solvent for oils, fats, waxes, and resins and for the extraction of essential oils in perfume manufacturing industries. Cyclohexene (C6H10) is used in the manufacture of maleic acid, cyclohexane carboxylic acid, and adipic acid. Methyl cyclohexane (C7H14) is used for the production of organic synthetics such as cellulose ethers. These compounds are used in different industries such as adipic acid makers, benzene makers, fat processors, fungicide makers, lacquerers, nylon makers, oil processors, paint removers, plastic molders, resin makers, rubber makers, varnish removers, and wax makers. 

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