Patent ID: 7321047

Claim:
A process of separating an individual tetrahydrocannabinol isomer of interest from a mixture containing two or more such isomers, which comprises: treating the mixture with an isocyanate or isothiocyanate of formula I: R—(CH 2 ) n —N═C═X where R represents an aromatic ring optionally substituted with one or more electron withdrawing groups, with the proviso that R is not 3,5-dinitrophenyl n=0 or 1 and X is oxygen or sulphur; so as to produce a crytallizable THC compound of formula II: wherein X, n and R are as defined above, R′ is a C 3 -C 10 alkyl group and the dotted lines indicate optional unsaturation; forming a solution of the compound of formula II so formed in an organic solvent; separating the compound of formula II by crystallization from the solution in isolation of other THC derivatives; and hydrolyzing the compound of formula II to form the individual tetrahydrocannabinol isomer of interest.