Glycidic acid esters ketones

By increasing the temperature over > 300°C, the phenyl glycidic acid esters are converted to phenyl acid esters. That occurs in a consecutive decarbonylation of a-ketone carboxylic acid esters as intermediate. In the case of p-tert-butyl glycidic acid ester in the presence of a boron-pentasil zeolite at 350 °C the ratio between a-ketone carboxylic acid ester and the phenyl acetic acid ester is 65 35. 

Aromatic and aliphatic aldehydes have been prepared in good yields by the decarboxylation and isomerization of the corresponding glycidic acids. Esters of the latter are obtained by treating a ketone with ethyl chloro-acetate in the presence of sodium amide (method 127). The glycidic esters are first converted to the sodium salts with sodium ethoxide and then treated with aqueous hydrochloric acid under gentle reflux. By this procedure, a-phenylpropionaldehyde has been prepared from acetophenone in an over-all yield of 38%. Other details have been discussed. ... 

Darzens-Claiscn reaction Glycidic acid esters from ketones and a-halogenocarboxylic acid esters... 

Sodium alcohol (s. a. under Cu and Ni(CO)J Darzens-Claisen reaction Synthesis of ketones from aldehydes via glycidic acid esters... 

Glycidic acid esters from ketones GO G-------G GOOR... 

Instead of a-halo esters, related reactants can be used e.g. the a-halo derivatives of ketones, nitriles, sulfones and A,A-disubstituted amides. The Darzens condensation is also of some importance as a synthetic method because a glycidic acid can be converted into the next higher homolog of the original aldehyde, or into a branched aldehyde (e.g. 5) if the original carbonyl substrate was a ketone ... 

A number of glycidates are important intermediates in the synthesis of fragrance materials. A few glycidates are fragrance materials in themselves. They are prepared either by epoxidation of the corresponding acrylates or by condensation of aldehydes or ketones with a-chloro substituted fatty acid esters (Darzens reaction). 

This knowledge was applied for even more complicated, bifunctional compounds such as phenyl glycidic acid methyl ester 3 to yield alpha-ketone carboxylic acid esters 4 such as 3-phenylpyroracemic acid methylesters (Eq. 15.2.2). 

Darzens condensation. Formation of a- and (i-epoxy esters (glycidic esters) by the condensation of aldehydes or ketones with esters of a-haloacids the corresponding thermally unstable glycidic acids yield aldehydes or ketones on decarboxylation. 

Since glycidic esters can usually be prepared from carbonyl compounds and chloroacetic esters, hydrolysis of the ester group and decarboxylation of the resulting glycidic acid gives as end-product the aldehyde containing one carbon atom more than those in the aldehyde or ketone ... 

Modified Darzens-Claisen reaction Aldehydes from ketones via glycidic acid tertAmiyX esters Synthesis with addition of 1 -atom... 

Methyl phenylethyl ketone Methyl 2-phenylethyl ketone. See Benzylacetone 3-Methyl-3-phenyl glycidic acid ethyl ester. See Ethyl methylphenylglycidate Methylphenylglyoxal. See 1-Phenyl-1,2-propanedione Methyl phenylglyoxalate CAS 15206-55-0 EINECS/ELINCS 239-263-3 Synonyms Benzeneacetic acid, a-oxo-, methyl ester Methylbenzoylformate Methyl a-ketophenylacetate Methylphenylglyoxylate Oxo-phenylacetic acid methyl ester Classification Aromatic ester Empirical CgHaOs... 

Oxiranecarboxylic acids 41 (glycidic acids) can be converted into a,P epoxy diazomethyl ketones 42 via mixed anhydrides. It was found that photolysis of these compounds in the presence of alcohols gave yhyunsaturated esters 44. It is thought that nucleophilic attack of the alcohol on the ketene 43 results in epoxide ring opening. The E olefin isomer is predominately formed, although small quantities of Z esters are also isolated (< 10%). Conveniently non-racemic, chiral substrates are readily prepared via Sharpless asymmetric epoxidation of allylic alcohol 39, followed by... 

Apart from the reaction of cyclohexanecarboxylic acid with methyllithium, cyclohexyl methyl ketone has been prepared by the reaction of cyclohexylmagnesium halides with acetyl chloride or acetic anhydride and by the reaction of methylmagnesium iodide with cyclohexanecarboxylic acid chloride. Other preparative methods include the aluminum chloride-catalyzed acetylation of cyclohexene in the presence of cyclohexane, the oxidation of cyclohexylmethylcarbinol, " the decarboxylation and rearrangement of the glycidic ester derived from cyclohexanone and M)utyl a-chloroj)ropionate, and the catalytic hydrogenation of 1-acetylcycIohexene. "... 

Cyclopropanatioru The ylide I reads with a,/j-unsaturated ketones to form cyclopropanecarboxylic acids in good yield. The reaction with ketones gives glycidic esters 60% yield). 

In the synthesis of optically active aryl glycidic esters, Julia66 type epoxidation (triphasic system of NaOH/aqueous hydrogen peroxide, hexane and a polyamino acid) of an unsaturated ketone gives excellent yields of the required epoxide67. A potent and selective leukotriene antagonist (SK F 104353) has been synthesized by a route where one of the key steps is this type of epoxidation (equation 8)68. 

Submitting a glycidic ester, to an alkaline hydrolysis at a temperature comprised between about 10° C. and about 40° C. for a period of time comprised between 6 and about 24 hours, to obtain an alkaline salt of the epoxyacid. Decarboxylating the compound in acidic ambient, at a temperature comprised between aobut 10° C. and about 40° C., for a period of time comprised between about 1 and about 8 hours, to obtain the ketone. Source Cannata 1991... 

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