Preparation of a range of NNN′N′-tetrasubstituted 1,8-diaminonaphthalenes

Abstract

Alkylation of 1,8-bis(methylamino)naphthalene with difunctional reagents leads to a series of 1,5-dimethylnaphtho[1,8-bc]-1,5-diazacycloalkanes(1)–(5), to 1,5-dimethylbenzo[g]naphtho[1,8-bc]-1,5-diazacyclononane (6), and to 1,5-dimethylnaphtho[1,8-bc]-1,5-diaza-8-oxacyclodecane (7). A variety of attempts to develop a selective preparation of 1,8-bis(methylamino)naphthalene are reported. The preparation of 9,9-dimethylnaphtho-[1,8-bc]-1,5-diazabicyclo[3.3.1]nonane (8), naphtho-[1,8-bc]-1,5-diazabicyclo[3.2.2]nonane (9), and naphtho-[1,8-bc]-1,5-diazabicyclo[3.3.3]undecane (10) from 1,8-diaminonaphthalene are described. Reaction of appropriate 1,4- and 1,5-dihalides with 1,8-diaminonaphthalene leads to 1,8-bis-(1-pyrrolidinyl)naphthalene (11), 1,8-bis(1,3-dihydroisoindol-2-yl)naphthalene (12), 1,8-bis-(1-piperidinyl)naphthalene (13), and 1,8-dimorpholinonaphthalene (14). Nitration of 2,7-dimethylnaphthalene gives a mixture from which 2,7-dimethyl-1,8-dinitronaphthalene may be isolated; this is reduced and alkylated to give 1,8-bis(dimethylamino)-2,7-dimethylnaphthalene (15). 1,8-Bis(dimethylamino)-2,7-dimethoxynaphthalene (16) and 1,8-bis(diethylamino)-2,7-dimethoxynaphthalene (17) are similarly prepared by reduction and alkylation of 1,8-dinitro-2,7-dimethoxynaphthalene. Reaction of 2,2-dimethyl-1,3-dihydroperimidine with αα′-dibromo-o-xylene led, surprisingly, to (12) and 5-(2-propyl)benzo[g]naphtho[1,8-bc]-1,5-diazabicyclo[4.3.0]nonane (24).