Indoxyl-β- -glucuronide. its stable salts and analogs thereof are described, together with a process for the production thereof in which a compound of the formula:
where X is halogen and R is lower alkyl is reacted with a compound of the formula:
where R 1 is any common carboxyl-protecting group, X, Y, Z and Q are the same or different and selected from hydrogen, halogen, trihalogenated alkene, trihalo-methyl, nitro, saturated or unsaturated alkyl and an aromatic moiety in water and methylene chloride containing an alkali hydroxide in the presence of a phase transfer catalyst, with subsequent removal of the blocking groups and conversion to the desired stable salt.