Phenol → Coumarin

Participants

Reaction Steps

Scheme VIII describes the synthesis of 6-alkylaminocoumarins, as demonstrated by Structure 45, from phenol through a similar route as that described in Schemes I and II. A mixture of a phenol compound and a 3-ketoester such as ethyl 4,4,4-trifluoroacetoacetate are heated in refluxing toluene in the presence of TsOH to afford a coumarin compound e.g., Structure 43. Nitration of coumarin compounds (e.g., Structure 43) followed by hydrogenation give aminocoumarin compounds such as Structure 44. Sequential reductive alkylation provides dialkylamino-coumarin compounds as shown in Structure 45. Hydrogenation of a dialkylamino-coumarin compound (e.g., Structure 45) affords compounds Structure 46.

Provenance & Evidence