4-Chloro-2-methylphenol (I) is condensed with 2,4,6-trichloroaniline (II) by heating to 120-140 C with amyl nitrite for 18 hours. The excess phenol is removed in vacuo; the residue is adsorbed on silica gel, applied to the top of a silica gel column and the crude phenolic fraction isolated by elution with hexane/acetone (95:5). The phenolic fraction, which contains 2-methyl-2'4,4',6-tetrachlorobiphenylol (III) and other isomers, is dissolved in dimethyl sulfoxide, anhydrous sodium carbonate is added, and the mixture is then heated with stirring at 160 C for 2 hours. The cyclization product, 1,3,8-trichloro-6-methyldibenzofuran (MCDF) is isolated by column chromatography and further purified by crystallization from methanol or methanol/anisole.