Abstract
The benzyne reaction of 1-(2-bromo-4, 5-dimethoxyphenethyl)-1, 2, 3, 4-tetrahydro-6-hydroxy-7-methoxy-2-methylisoquinoline (13) was examined by using sodium methylsulfinylmethanide and the dibenzo [b, g] azecine (16) was obtained. The 1-halogenophenethylisoquinoline (14) also yielded the corresponding dibenzo [b, g] azecine (17) under the similar conditions. The reductive deoxygenation of (16) and (17), followed by desulfurization of 14-(methylthio) methyl derivative (18) and (19) gave the corresponding 14-methyl derivative (20) and (21), respectively. The similar ring expansion occurred also in the case of 1-halogenobenzylisoquinoline (15) to give the dibenzo [b, f] azonine (29), which was converted to the 13-methyl derivative (31).
