A new multicomponent reaction: unexpected formation of derivatizable cyclic a-alkoxy isothioureas.

Organic & biomolecular chemistry

PubMedID: 25655707

Brockmeyer F, Morosow V, Martens J. A new multicomponent reaction: unexpected formation of derivatizable cyclic a-alkoxy isothioureas. Org Biomol Chem. 2015;.
An unexpected formation of cyclic a-alkoxy isothioureas has been achieved. As is known, the heterocyclic imines 2,5-dihydro-1,3-thiazoles are convertible to bisamides with the aid of a carboxylic acid and an isocyanide (Ugi reaction). Herein, it is shown that 2,5-dihydro-1,3-thiazole S-monoxides-the respective a-sulfinyl imines-are characterized by an altered reaction behavior. In a hitherto unknown multicomponent reaction the a-sulfinyl imines react with an isocyanide under acidic conditions in an alcoholic solution to the respective a-alkoxy isothioureas in good yields. In addition to the investigations on this unexpected synthesis the regioselectivity of the acylation of the synthesized compounds is described. A rearrangement, which is accelerated by EDC and HOBt, between both possible regioisomers was found.