FREMGANGSMAADE TIL FREMSTILLING AF 7-HYDROXYCUMARANER

In the preparation of a 7-hydroxycoumaran of the formula in which Z is a hydrogen atom or a substituent which is inert under the subsequent reaction conditions, R1 is a hydrogen atom or a C1 to C4-alkyl radical, and n is 1, 2 or 3 wherein a pyrocatechol of the formula is reacted with an allyl compound of the formula in which Y is a halogen atom, a C1 to C4-alkyl-sulphonate radical or an aryl-sulphonate radical, to form the mono-ether of the pyrocatechol in a first stage, and in a second stage, of the pyrocatechol monoether formed in the first stage is rearranged to a 3-alkenylpyrocatechol, and in a third stage the 3-alkenylpyrocatechol formed in the second stage, is cyclized, the improvement which comprises stages. (b) carrying out the second stage at a pH of about 2-8. Advantageously glycol monomethyl ether is employed as the solvent in all stages and the third stage is carried out with a residence time of about 1-30 minutes and with a narrow residence time spectrum corresponding to a Bodenstein-index 5, optionally in the presence of an iron salt.