Methyl 2-oxocyclohexanecarboxylate

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. -... 

The preferred tautomer of the products derived from the condensation reaction of phenylenediamine with cyclic /3-keto esters (Scheme 5) is highly dependent on the structure of the /3-ketoester <2005JHC1001>. H and 13C NMR analysis of the l,5-benzodiazepin-2-one 34, formed from methyl 2-oxocyclohexanecarboxylate under micro-wave conditions, indicated the presence of the C(4)-N(5) imine <2005JHC1001>. In contrast, the products arising from condensation with methyl 2-oxocyclopentanecarboxylate and methyl l-alkyl-4-oxopiperidine-3-carboxylates were found to be in the enamine form 35. 

The second example of a Dieckmann condensation shown earlier produces ethyl 3-methyl-2-oxocyclohexanecarboxylate in 90% yield. What other cyclic product might have been formed in this reaction Explain why the actual product is favored rather than this other product. 

Methyl 2-oxocyclohexanecarboxylate Cyclohexanecarboxylic acid, 2-oxo-, methyl ester (9) (41302-34-5)... 

Ethyl 4-methyl-2-oxocyclohexanecarboxylate and ethyl 6-methyl-2-oxocyclohexane-carboxylate... 

Potent nucleophiles can be generated from C-H acidic compounds by deprotonation. Diethyl malonate reacted with diethyl cyclopropane-1,1-dicarboxylate (1) in the presence of sodium ethoxide to give tetraethyl butane-1,1,4,4-tetraoate (2). Isopropylidene cyelo-propanedicarboxylate (3) underwent an analogous reaction when treated with dimethyl malonate or methyl 2-oxocyclohexanecarboxylate. ... 

A mixture of methyl and ethyl 2-oxocyclohexanecarboxylate, available from Aldrich Chemical Company, Inc., may also be used. The product obtained is a mixture of methyl and ethyl 2-methylcyclohexene-l-carboxylates. 

Cyclocondensation of 2-aminopyridine and its methyl derivatives with ethyl 2-oxocyclohexanecarboxylate in a mixture of polyphosphoric acid and phosphoryl chloride gave 1,2,3,4-tetrahydro-l 1 //-pyrido[2,l -b]-quinazolin-ll-one and its 6-, 7-, 8-, and 9-methyl derivatives (87JMC1543). 

Methyl (l/ , 3S, 4S )-3-Dimethyl(phenyl)sihT4-inetliyl-5-oxocyclohexanecarboxylate (2) Typical Procedure18 ... 

C8H1203 3-methyl-4-oxocyclohexanecarboxylic acid 101567-36-6 22.00 1.0630 2 14778 C8H15N octahydro-1 H-indole 4375-14-8 20.00 0.9472 1... 

C9H13N30 3-(2-hydroxyethyl)-3-methyl-1-phenyltriazene 21600-45-3 418.15 36.079 2 17487 C9H1403 ethyl 4-oxocyclohexanecarboxylate 17159-79-4 494.65 43.370 2... 

In a similar way, l-nonyl-3-oxocyclohexanecarboxylic acid ethylene ketal (VI) has been ring opened [37] to methyl 5-nonyl-5-hexenoate (VII) by anodic oxidation at a C anode in methanol containing K2CO3 ... 

Thus an almost quantitative yield of ethyl l-(hydroxymethyl)-2-oxocyclo-hexanecarboxylate is obtained from ethyl 2-oxocyclohexanecarboxylate and aqueous formaldehyde in the presence of calcium oxide 687 and 2-butanone and formaldehyde in sodium hydroxide solution give a 70% yield of 4-hydroxy-3-methyl-2-butanone, whence 3-methyl-3-buten-2-one is formed in 74% yield by removal of water.688 Hydroxymethylation of acetone689 and of co-nitrotoluene (phenylnitromethane)690 have also been reported. 

Benzenetriols on cyclocondensation with hydroxybenzoic acids gave 1,3-dihydroxyxanthones which were converted into various 0-derivatives containing carboxyl or amino groups.Several xanthones [e.g., (165)] have been synthesized by ring closure of the ketones (164) with ethanolic potash.Benzoxanthones are represented in nature by several compounds such as the quinone bikaverin. Several members of this class [e.g., (166)] were prepared by base-induced condensation of 2-hydroxyacetophenones with dimethyl homophthalates, and reduced benzoxanthanone (167) which is potentially of interest as an antitumour compound, was obtained by condensation of 2-methylchromone-3-carboxylic acid with methyl 4-oxocyclohexanecarboxylate. 

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