O-Xylene → 3-(4-Cyano-4-(3,4-dimethoxyphenyl)-5-methylhex-1-yl)-1,2,3,4-tetrahydro-6,7-dimethoxy-2-methylisoquinoline

Beteiligte Stoffe

Reaktionsschritte

Alternatively, one may convert the ester group of compound 11.1 directly to the cyano group by treatment with 2 equivalents of dimethylaluminum amide (S. Weinreb, et al., Tetrahedron Lett., 4907 (1979), incorporated herein by reference). This reaction is performed in a suitable aprotic hydrocarbon solvent, preferably a high-boiling solvent such as xylene. Two equivalents of Me2AlNH2 in CH2Cl2 is added to a solution of the ester of formula 11.1 in the appropriate solvent and heated at 80°-170° C., preferably in refluxing xylene, for about 30 minutes to about 20 hours. The reaction is followed by TLC. For example, 3-[4-(3,4-dimethoxyphenyl)-4-isopropyl-4-(carbomethoxy)butyl]-6,7-dimethoxy-N-methyl-1,2,3,4-tetrahydroisoquinoline (11.1) is heated in refluxing xylene with Me2AlNH2 for about 15 hours to yield 3-[4-(3,4-dimethoxyphenyl)-4-isopropyl-4-cyanobutyl]-6,7-dimethoxy-N-methyl-1,2,3,4-tetrahydroisoquinoline (1).

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