5,12-Diacylated-5,6,11,12-tetrahydrodibenzo[b,f][1,4]-diazocines and related compounds

Both N,N′ -(o-phenylene)diformamide (1) and N,N′ -(4-chloro-1,2-phenylene)diformamide (30) reacted with α,α-dibromo-o-xylene (2) in DMF at 95–100° to give 5,6,11,12-tetrahydrodibenzo-b,f]1,4]diazocine-5,12-dicarboxaldehyde (3a) and the corresponding 2-chloro derivative (3b). With potassium hydroxide in ethylene glycol at 110°, 3a and 3b were selectively saponified to the 5-carboxaldehyde derivatives (4) and either 21a or 22a. Reacylation of the latter led to a series of 5,12-unsymmetrically diacylated derivatives, 5–18. Additionally, 4 was subjected (a) to a basecatalyzed addition to acrylonitrile to give the 12-cyanoethyl derivative (19) and (b) alkylation with α-bromotoluene to give the 12-benzyl compound (20). Saponification of both carboxaldehyde groups in 3a,b required potassium hydroxide in ethylene glycol at 135° and gave the N,N′ -unsubstituted heterocycles (23 and 24) ; these were subsequently reacted with several aldehydes to yield the 5,12-methano derivatives (25–29) .