Synthesis of fused tetracycles from the nitration products of benzo[b]thieno[2,3-c]pyridines

The nitration products of benzob]thieno2,3-c]pyridines were used in the synthesis of new fused tetracyclic heterocyclic systems, which are structural analogs of natural ellipticine and olivicine alkaloids. Closure of the pyridine ring gives products only with linear ring fusion. This behavior was explained using the steric strain-stability principle and complete optimization of the structure of these products with a PCMODEL program and MMX force field in conjunction with the -electron approximation.L. M. Litvinenko Institute of Physical Organic and Coal Chemistry, National Academy of Sciences of Ukraine, 340114 Donetsk, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 406–411, March, 1997.