Synthesis of di- and triamino-1,1 ': 3 ',1 ''-terphenyls from arylethylidene- and arylidenemalonodinitriles

A three-step synthesis of several di- or triamino-m-terphenyls 19 - 23 from 3- or 4-nitrobenzylidenemalonodinitriles 1 and 1-[3- or 4-nitro(or amino)p henyl]ethylidenemalonodinitriles 2 is reported. Gewald's method was applied for a one-pot preparation from 1 and 2 of 5'-amino[1,1':3',1 "-terphenyl]- 4',6'-dicarbonitriles 5 - 15 which bear the nitro or amino/nitro groups on the side rings of the terphenyl system. An attempt to optimize yields of th e terphenyls 5 - 15 by selective introduction of the nitro or amino functio ns on the phenyl groups of starting dinitriles 1 and 2 was carried out. Com pounds 5 - 13 were smoothly reduced with tin and hydrochloric acid to affor d 5'-amino[1,1':3',1 "-terphenyl]-4',6'-dicarbonitriles 14 - 18 having only the amino groups on the side benzene rings. The terphenyls 14 - 18 were de nitrilated to yield di- or triamino-1,1':3',1 "-terphenyls 19 - 23. The dec yanation reaction was carried out by heating 14 - 18 for 4 h at 220 degrees C in a pressure vessel ( similar to 2.5 MPa) with ethanolic sodium hydroxi de solution. (C) 1998 Elsevier Science Ltd. All rights reserved.