“…Levamisole (2,3,5,thiazole hydrochloride), (1), has shown powerful broad-spectrum anthelmintic properties (Thienpont, Vanparijs, Raemaekers, Vandenberk, Demoen, Allewijn, Marsboom, Niemegeers, Schellekens & Janssen, 1966;Englemann & Richardson, 1986) as well as a wide variety of other useful medicinal characteristics (Van Belle, 1972;Chan & Kellen, 1975;Chirigos, 1977Chirigos, , 1981Symoens & Rosenthal, 1977;Hara, Kayama & Fukushima, 1981). Analogs of (1) have been a subject of considerable interest in recent years (Bell & Wei, 1976;Bhargave, Lee, Huang, Cunningham & Agrawal, 1977), such as (2) (Fenichel, Gregory & Album, 1976;Tagliabue, Allesandri, Polentarutti, Montovani, Falantano, Vecehi, Garattini & Spreafico, 1978) and (3) (Hara et al, 1981), and have prompted research into newer methods to obtain highly substituted 2H-benzimidazole-2-thione systems. During the course of some work with thiazoloimidazole acetic acids (Radhakrishna & Berlin, 1978), we had the occasion to prepare 4,5-(8-ehlorochroman)-[2,3-d]imidazole-2-thio (4).…”