Benzene → Chroman

Participants

Reaction Steps

Thus, a known alcohol of general formula (V-1) is reacted with an organic sulfonyl chloride in the presence of pyridine in the conventional manner to give a sulfonic acid ester of general formula (VI-1) and this sulfonic acid ester is then reacted with potassium phthalimide to give an N-substituted phthalimide of general formula (VII), which is further treated with hydrazine to give an amine of general formula (VIII). This amine of general formula (VIII) is reacted with 0.9 to 1.1 molar equivalents of an isothiocyanate in an inert solvent such as methylene chloride, dichloroethane, benzene, methanol, etc. at a temperature of room temperature to reflux temperature to give a 3,4-dihydrobenzopyran derivative of general formula (I-1b). And the amine of general formula (VIII) is reacted with 0.9 to 1.2 molar equivalents of methylisothiourea in an inert solvent such as methanol, ethanol, etc. at a temperature of room temperature to reflux temperature to give a 3,4-dihydrobenzopyran derivative of general formula (I-1c). The separation and purification of 3,4-dihydrobenzopyran derivative (I-1b) or 3,4-dihydrobenzopyran derivative (I-1c) from the reaction mixture can be carried out in the conventional manner.

Provenance & Evidence