The Reaction of Hydrogenated 3,3-Dimethylisoquinolines with Hexamethylenediisocyanate

By reaction of 1-R-3,3-dimethyl-1,2,3,4-terahydroisoquinolines (R=H, Me) with hexamethylenediisocyanate (HDI) the corresponding N,N′-(hexane-1,6-diyl)bis(1-R-3,3-dimethyl-3,4-dihydroisoquinolin-2(1H)-carboxamides have been synthesized. The reaction of HDI with 1,3,3-trimethyl-3,4-dihydroisoquinoline leads to (2Z,2Z′)-N,N′-(hexane-1,6-diyl)bis2-(3,3-dimethyl-3,4-dihydroisoquinolin-1(2H)-ylidene) acetamide, the similar product have been obtained for the corresponding benzo[fisoquinoline. The both amides bis-derivatives were obtained earlier by direct counter synthesis by Ritter cyclisation. When HDI reacted with enaminoamides of the 6,7-diethoxy-1-methylidene-3,3-dimethyl-1,2,3,4-tetrahydroisoquinoline series, carbamylation occurred at the β-carbon atom of the enamine fragment, resulting in the formation of corresponding bis-derivatives of malonic acid diamide.