New arylazogrisans and their preparation

The invention comprises grisan derivatives of the general formula:- wherein Ar stands for the phenyl radical, optionally substituted by alkyl, alkoxy or carbamyl groups or with halogen atoms, together with a process for their preparation by coupling the appropriate aryl or substituted aryl diazonium salt with griseofulvic acid, preferably in the form of its alkali metal salt and at a temperature between 0 DEG and 10 DEG C. in the presence of a buffer which maintains the pH at 6-8. Examples detail the use of diazotised aniline, p-chloraniline, o-anisidine, o-phenetidine, o-n-butoxyaniline, p-anisidine, o-toluidine, p-n-butylaniline, and p-aminobenzamide. The compounds exhibit anti-fungal properties similar to griseofulvin.