59950-40-2Relevant academic research and scientific papers
Out-Basicity of 1,8-bis(dimethylamino)naphthalene: The experimental and theoretical challenge
Ozeryanskii, Valery A.,Pozharskii, Alexander F.,Antonov, Alexander S.,Filarowski, Alexander
, p. 2360 - 2369 (2014/04/03)
A possibility of non-conventional two-step protonation of 1,8-bis(dimethylamino)naphthalene (proton sponge) is discussed. Unlike the generally accepted mechanism, involving relatively slow direct penetration of a proton into the cleft between the peri-NMe2 groups, it consists of the rapid addition of a proton to the out-inverted NMe2 group with the subsequent slower rotational transfer of the proton into the inter-nitrogen space to produce a stable chelated cation. The following approaches were employed during the work: (1) competitive hydrogen bond formation in a specially designed alcohol in which the OH group might chelate either the proton sponge 1-NMe2 group or another basic center (N,N-dimethylaniline) of known basicity; (2) measuring the basicity of naphtho[1,8-b,c]diazabicyclo[3.3.3] undecane considered to be a close analogue of the proton sponge capable exclusively of out-protonation; (3) X-ray, spectral and DFT studies of structure, energy and stereodynamics of compounds obtained, including their conformers. For the first time, the pKa value of an organic base with a perfectly flat nitrogen atom is reported. The final conclusion is made that both pathways of proton sponge protonation, traditional and non-conventional, contribute in parallel with a still undefined ratio. The estimated out-basicity of the proton sponge is at least 5.5 orders of magnitude lower than the directly measured in-basicity. the Partner Organisations 2014.
Preparation of a Range of NNN'N'-Tetrasubstituted 1,8-Diaminonaphthalenes
Alder, Roger W.,Bryce, Martin R.,Goode, Nigel C.,Miller, Nigel,Owen, Judith
, p. 2840 - 2847 (2007/10/02)
Alkylation of 1,8-bis(methylamino)naphthalene with difunctional reagents leads to a series of 1,5-dimethylnaphtho-1,5-diazacycloalkanes (1)-(5), to 1,5-dimethylbenzonaphtho-1,5-diazacyclononane (6), and to 1,5-dimethylnaphtho-1,5-diaza-8-oxacyclodecane (7).A variety of attempts to develop a selective preparation of 1,8-bis(methylamino)naphthalene was reported.The preparation of 9,9-dimethylnaphtho-1,5-diazabicyclononane (8), naphtho-1,5-diazabicyclononane (9), and naphtho-1,5-diazabicycloundecane (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)benzonaphtho-1,5-diazabicyclononane (24).
