Isopiperitenol prepn from isobutylene derivs - 3-methyl-2-buten-1-ol and 3,3-dimethyl acrolein heated in liquid phase using acids as catalysts

摘要

Isopiperitenol (I), which can be hydrogenated to menthol and is an inter for synthesis of tetrahydrocannabinols, is prepd by heating 3-Me-2-butene-1-ol with 3,3-dimethylacrolein for =1 hr, at 165-300 degrees C, in the presence of 0.01-5 wt. % w.r.t. sum of reaction components, of an acid as catalyst, in the liq. phase, whereby citral formed initially is cyclised to (I). Process is a modification of higher mol wt alpha, beta-unsatd. aldehyde prepn disclosed in DT 2157035, by reacting an allyl alcohol with an alpha, beta-unsatd aldehyde.