Thiocarbamoylation of 1,2,3,4-tetrahydroisoquinoline enamines with phenyl isothiocyanate

Reactions of 1,3,3-trimethyl-3,4-dihydroisoquinoline and its benzof] derivative with phenyl isothiocyanate gave the corresponding enamino thioamides. Enamino ester, enamino amides, and enamino nitriles of the 1,2,3,4-tetrahydroisoquinoline series reacted with phenyl isothiocyanate in a similar way. The resulting enamino thioamides underwent acylation with acid chlorides at the β-carbon atom of the enamino fragment. The structure of the obtained enamino thioamides is stabilized by intramolecular H-bonding.