Trifluoroacetic acid → 19176-99-9

Participants

Reaction Steps

The compounds listed in the Examples 54, 55 and 56 below were made starting from a common cyclohexanone precursor. For the synthesis of the compounds in Examples 54 and 55 below, 4,4-dimethylcyclohexanone was converted by a four-step process into 1-(4,4-dimethylcyclohexyl)ethanone. The 4-step process is similar to that given in Example 53: the Wittig reagent generated as in Example 53 from (methoxymethyl)triphenylphosphonium chloride and NaH in THF was used to form the corresponding enol ether product from 4,4-dimethylcyclohexanone: (4-methoxymethylene-1,1-dimethyl-cyclohexane). This enol ether was hydrolyzed using TFA:DCM to generate the corresponding aldehyde. This aldehyde was treated with MeMgBr in THF/Et2O to give a methylcarbinol derivative which was then oxidized using PCC in DCM to give the desired 1-(4,4-dimethylcyclohexyl)ethanone. Also in an analogous fashion to the process disclosed in Example 53, this ketone was then treated with pyrrolidone hydrotribromide to give the 2-bromoketone derivative, and this bromoketone intermediate was subsequently treated with the appropriate thiourea derivatives in MeOH to produce the products shown in Examples 54 and 55 after hydrolysis of the esters, purification of the acids, and generation of the sodium carboxylate salts.

Provenance & Evidence