Abstract
Synthetic procedures of 1, 2-dihydro-6H-1, 5-methanobenzo [d][1, 2] diazocin-3 (4H)-one (XV) and 9-methoxy-4, 11-dimethyl-1, 2, 3, 4-tetrahydro-6H-1, 5-methanobenzo [d][1, 2] diazocine (XXII) by using ethyl isoquinoline-4-carboxylate (II) and m-methoxyphenylacetone (XVI) as a starting material, respectively, were investigated. Methy 1, 2, 3, 4-tetrahydroisoquinoline-4-acetate (XIII) was prepared by catalytic reduction of II, lithium aluminum hydride reduction of the carbethoxy group to the hydroxymethyl, conversion to the N-benzyl derivative, cyanization of the corresponding bromide, methanolysis of the nitrile, and debenzylation. The amino ester was nitrosated to the N-nitroso derivative which on reduction with zinc and acetic acid yielded XV. 5-(m-Methoxyphenyl)-2, 6-dimethyl-4, 5-dihydropyridazin-3 (2H)-one (XIX) was prepared by condensation of m-methoxyphenylacetone with ethyl bromoacetate, hydrolysis of the ester and condensation of the resulting keto acid with methylhydrazine. XIX was reduced to the 1, 4, 5, 6-tetrahydro derivative which was converted to 9-methoxy-4, 11-dimethyl-1, 2-dihydro-6H-1, 5-methanobenzo [d][1, 2] diazocin-3 (4H)-one (XXI) by the Pictet-Spengler reaction. XXI was reduced to XXII with lithium aluminum hydride. Configurations of XX, XXI and XXII were examined by NMR spectra, and these are assumed to exist in conformations XX' and XXI'.
