Resorcinol → 3-Hydroxy-8,9,10,11-tetrahydrobenzo[b]cyclohepta[d]pyran-6(7H)-one

Participants

Reaction Steps

The Applicant has now found that this compound can be synthesized in two chemical stages. The first stage consists of condensing in a strong acid (such as sulphuric acid, trifluoroacetic acid or methanesuiphonic acid) 2-carbetoxycycloheptanone with resorcinol, intermediate 3-hydroxy-8,9,10,11-tetrahydrocyclohepta[c]chromen-6(7H)-one is isolated by precipitation using an alcohol/water mixture (for example by adding ethanol then water). In a second stage, sulphonylisocyanate chloride is converted, in toluenic solution, to sulphamoyl chloride, by the action of formic acid, then condensed with the previous intermediate dissolved in a solvent such as DMA. The reaction medium is treated with water and extracted by an organic solvent (preferably 2-methyltetrahydrofurane: MeTHF), and crude compound 1 is then precipitated from the organic phase by adding an antisolvent (preferably methylcyclohexane). Finally pure compound 1 is obtained by recrystallization of the crude product by dissolution in acetone or ethyl acetate while hot and precipitation by adding an antisolvent (preferably methylcyclohexane).

Provenance & Evidence