Study of acylation reactions in 3-aminocarbostyril derivatives

Condensed isoquinolines. 37.* Heterocyclization using 3-(arylamino)- and 3-(hetarylamino)isoquinolin-1(2H)-ones

“…The difference in the chemical shifts of these protons ( ~ 0.64) is comparable to the difference noted for compound 7 ( ~ 0.73,  H-5 in starting 1a is 7.27 ppm [9]) and higher than the difference noted for compounds 4a and 4b ( ~ 0.12 for 4a and  ~ 0.42 for 4b,  H-5 in starting compound 1b is 7.58 ppm [13]). This behavior may be the result of more efficient conjugation between the isoquinoline and pyrimidine rings in 13 or, correspondingly, the pyridine ring in compound 7.…”

“…The 4-arylidene derivative of the type 3 formed in the initial step of this reaction converts to compound 4a as the result of intramolecular Friedel-Crafts type alkylation and subsequent oxidation of the electrophilic substitution product. Changes in the spin system of the 4-methoxyaniline fragment in the starting 3-aminoisocarbostyryl [9] in addition to the GC/MS and elemental analysis data indicated formation of products of aromatic electrophilic substitution. The 1 H NMR spectrum of dibenzo[b,f][1,8]naphthyridine 4a shows three aromatic proton signals from a 1,2,4-trisubstituted benzene ring ( Table 2).…”

“…The 1 H NMR spectrum of product 5b displays a sole one-proton singlet for H-14, while all aromatic proton signals have double intensity, which corresponds to a molecule with very high symmetry ( Table 3). The signal of the NH groups at 9.25 ppm is very broad and shifted upfield relative to the amide proton in starting isocarbostyryl 1a at 10.64 ppm [9] due to rapid exchange with water present in the DMSO-d 6 solvent.…”

“…Attempts to obtain condensation products of compounds 1a,b and 2a-f in 2-propanol in the presence of piperidine were also unsuccessful, while carrying out this reaction in acetic anhydride led predominantly to acylation [9]. .…”

Synthesis of azolo[a]pyridines from 5-(bromomethyl)hept-4-en-3-one and 5-bromopent-3-en-2-one derivatives

“…On account of their relatively poor availability they were used predominantly for the production of pyrroles in reactions with primary amines [1][2][3][4][5]. We recently found convenient methods for the synthesis of the azolo[a]pyridine system derivatives on the basis of (2Z)-4-bromo-1,3-diphenyl-2-buten-1-one (γ-bromodypnone) and its derivatives [6][7][8]. While continuing investigations in this direction we turned to γ-halo ketones of the aliphatic series.…”