ChemInform Abstract: PERI‐NAPHTHYLENEDIAMINES. V. SYNTHESIS OF HYDROGENATED DERIVATIVES OF 10‐DIMETHYLAMINOBENZO(H)QUINOLINE AND QUINOLINO(7,8:7′,8′)QUINOLINE

Abstract

Ausgehend von Perimidin (I) werden die Synthesen einer Reihe von Derivaten des l0‐Dimethylaminoben‐ zolhlchinolins (XVIII) und des Chinolino[7,8 : 7′,8′]chinolins (XlX) beschrieben.

Naphthalene 'proton sponges'

“…This approach was used, in particular, in the synthesis of 1,8-bis(dialkylamino)- In a similar way, the acenaphthene `sponges' 48, 49, 25 4-halogeno-and 4,5-dihalogeno-1,8-bis(dimethylamino)naph-thalenes 50 ± 53, 27,28 and partially hydrogenated derivatives of 10-dimethylaminobenzo[h]quinoline 25 and quinolino[7,8:7 H ,8 H ]-quinoline 26 were synthesised. 29 It should be noted that quaternisation of 6-halogeno-1,3dimethyl-2,3-dihydroperimidines 54a,b gives a mixture of isomeric salts 55a,b and 56a,b in comparable amounts. Separation of this mixture is not required, since methylation of the isomeric N,N,N H -trialkyl-substituted 1,8-diaminonaphthalenes formed upon alkaline treatment give the same final product.…”

“…Both of them entail the use of strong bases (sodium or potassium hydrides in anhydrous tetrahydrofuran 19 or potassium hydroxide in dimethyl sulfoxide) for the ionisation of N7H-bonds. 20 Obviously, under these conditions it is the N-anions of the original diamine and intermediate substitution products that undergo alkylation. The ionisation is favoured by the very high (in comparison with ordinary arylamines) NH-acidity of the diamine 1 (pK a = 24.5, DMSO, 25 8C), which is ascribed to the stabilisation of the N-anion 32 through IHB.…”

“…To obtain good yields of the compound 31, it is recommended to use hexametapol as a solvent instead of DMSO. 20 However, the alkylation of 1,8diamino-2,7-dimethoxynaphthalene 33 gives compounds 34 and 35 in low yields (40% and 21%, respectively). 22 The yields of the `proton sponges ' 37, 38 obtained by the alkylation of the diamine 36 are even lower.…”

A Novel Dimerization Mode of a Cyclic Ketene Imine

“…1,8‐Bis(dimethylamino)naphthalene is a stronger base than triethylamine, but non‐nucleophilic 19. With a p K a of 18.18 in acetonitrile20 and an autoprotolysis constant of 3×10 −29 for this solvent,21 a 0.06 M solution of “proton sponge” is approximately 2×10 −6 M in NC‐CH 2 − , sufficient to trigger the ionic chain via 20 . Proton sponge in CHCl 3 as solvent also initiated dimerization.…”

Heterocyclic superbases: retrospective and current trends

“…Derivatives [32] are unique analogs of diamine 11. Both compounds 18 and 19 are less basic than diamine 11 by approximately half an order of magnitude.…”