Dimethylformamide dimethyl acetal → Formononetin

Participants

Reaction Steps

Another known approach used for the synthesis of formononetin is the general method involving the addition of one carbon to 2-hydroxydeoxybenzoins and their cyclization to form isoflavones. The method introduced by Andrew Pelter (Pelter, Andrew, et al., Synthesis, 5:326 (1976)) involves the reaction of 2-hydroxydeoxybenzoins with N,N-dimethylformamide dimethylacetal (dimethoxydimethyl aminomethane) (two equivalents) in dry benzene. Refluxing a mixture of 2,4-dihydroxy-4'-methoxydeoxybenzoin with N,N-dimethylformamide dimethyl acetal in dry benzene for 4 hours gave formononetin in 85% yield. However, the use of the expensive reagent, N,N-dimethylformamide dimethyl acetal and dry benzene as solvent makes this an unattractive method for the commercial production of formononetin.

Provenance & Evidence