A. A. Harutyunyan

Synthesis of tetra- and pentaaza heterocyclic systems and benzimidazo[1,2- c ]quinazoline derivatives

Abstract5,6-Dihydropyrimido[5′,4′: 5,6]pyrido[1,2-a]benzimidazole and pyrimido[4′,5′: 4,5]pyrimido[1,6-a]-benzimidazole derivatives were synthesized starting from 3-[4-hydroxy-6-methyl(hydroxy)-2-phenylpyrimidin-5-yl]propanoic and 4-hydroxy-2-phenylpyrimidine-5-carboxylic acids. New 6-sulfanyl-substituted benzimidazo-[1,2-c]quinazolines were also prepared.

Synthesis of new fused penta- and hexacyclic polynitrogen systems from 1H-benzimidazol-2-ylacetonitrile

In recent time, fused polynitrogen heterocycles attract interest as promising pharmacologically active compounds exhibiting pronounced antiviral, immunosuppressive, antitumor, and other properties [1]. In continuation of studies directed toward searching for biologically active compounds in the series of nitrogen-containing heterocycles [2], the present communication reports on the synthesis of a derivative of novel 8H-pyrido[1′′,2′′ : 1′,2′]pyrimido[5′,4′ : 5,6]pyrido[1,2-a]benzimidazole heterocyclic system, as well of a tetrahydro derivative of the known benzimidazo[1,2-a]naphtho[2,1-g][1,8]naphthyridine system [3]. 1H-Benzimidazole-2-ylacetonitrile (I), being a C,N-binucleophile, is known to react with heterocyclic o-chloro aldehydes to give polycyclic compounds via tandem nucleophilic substitution pattern [3]. Analogous reactions of nitrile I with o-chloro aldehydes II and III in DMF afforded new fused polycyclic polyaza heterocycles IV and V, respectively. The product structure was confirmed by elemental analysis and IR and H NMR spectroscopy.

New general synthesis of benzo[4,5]imidazo[1,2-a]pyrimidine and benzo[4,5]imidazo[2,1-b]quinazoline derivatives

The reactions of benzene-1,2-diamine with 5-substituted 2-(alkylsulfanyl)-4-methylpyrimidin-6(1H)-ones and 2-(propylsulfanyl)- and 5-iodo-2-(propylsulfanyl)-3,4-dihydroquinazolines at 175–185°C under solvent-free conditions unexpectedly afforded benzo[4,5]imidazo[1,2-a]pyrimidine, benzo[4,5]imidazo[2,1-b]-quinazoline, and 2,2′-(benzene-1,2-diyldiimino)bis[pyrimidin-4(3H)-ones]. The described reaction is the first example of synthesis of these heterocyclic systems by fusion of benzimidazole to pyrimidine or quinazoline and is likely to follow ANRORC mechanism.

Synthesis of bisarylmethyl-substituted pyrimidines and quinolines

The condensation of 2-chloro-8-methylquinoline-3-carbaldehyde, 2-chloroand 2-chloro-7,8,9,10-tetrahydrobenzo[h]quinoline-3-carbaldehydes, 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carbaldehyde, 6-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carbaldehyde, and 2-chloropyrido[1,2-a]pirimidine-3-carbaldehyde with N-substituted anilines gave the corresponding diaryl(hetaryl)methanes.

One-step synthesis of pyrido[2,3-d]pyrimidines, amides, and benzoxazolylethylpyrimidine by condensation of substituted 3-(2-phenylpyrimidin-5-yl)propanoic acids with aromatic amines in polyphosphoric acid

Depending on the reactant structure, reactions of substituted 3-(2-phenylpyrimidin-5-yl)propanoic acids with 2-aminopyridine, p-toluidine, and 2-aminophenol in polyphosphoric acid afforded the corresponding N-(pyridin-2-yl)propanamides, 5-[2-(benzoxazol-2-yl)ethyl]pyrimidine, and pyrido[2,3-d]pyrimidinones.

Synthesis and Structure of New Substituted Pyrimidinone with Unsaturated Side Chain

Melting of a mixture of 5-substituted 2,4-dimethyl-1,6-dihydropyrimidin-6-ones with cinnamic aldehyde, 1-methylindoline-2,3-dione and 6-methoxy-2-chloroquinoline-3-carbaldehyde in the presence of ZnCl2 led to the formation of substituted pyrimidines with conjugated bonds in the position 2. The structure of synthesized compounds as 2-isomers was confirmed by 2D 1H NMR NOESY data.

Substituted 2-(2-Arylethenyl]pyrimidin-4(3H)-ones: Synthesis and Structure

Abstract5-Substituted 2,6-dimethylpyrimidin-4(3H)-ones were synthesized, and their structure was proved by X-ray analysis. Their reactions with aromatic aldehydes regioselectively afforded (Z)-2-(2-arylethenyl)- pyrimidin-4(3H)-ones whose structure was determined by one- and two-dimensional (NOESY) 1H NMR and X-ray analysis.

4-alkylated 2-(2,3,5-tri-O-acyl-β-D-ribofuranosyl)- and 2-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-1,2,4-triazine-3,5-diones

The alkylation of 2-(2,3,5-tri-O-acyl-β-D-ribofuranosyl)- and 2-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)- 1,2,4-triazine-3,5-diones with benzyl halides afforded the corresponding 4-benzyl derivatives whose structure was determined by spectral methods, including X-ray analysis. Some of the synthesized compounds were tested for antibacterial and antitumor activity.

Condensation of pyrido[1,2-a]pyrimidine with aromatic aldehydes. Synthesis of fused polycyclic pyrimidines

It is known that pyrido[1,2-a]pyrimidine derivatives exhibit a broad spectrum of biological activity such as antibacterial, fungicidal, antiviral, antitumor, anti-monoamine oxidase, etc. [1–3]. Syntheses on the basis of 2-chloro-4-oxo-4H-pyrido[1,2-a]pyrimidine3-carbaldehyde leading to the corresponding 3-(diarylmethyl) derivatives and pentacyclic tetraaza heterocycle were described previously [4, 5]. In continuation of studies on the synthesis of pyridopyrimidine derivatives, the present communication reports the condensation of 2-hydroxy-4H-pyrido[1,2-a]pyrimidin-4-one (1) [6] with 4-nitrobenzaldehyde (2a), 2-chloroquinoline-3-carbaldehyde (2b), and 2-hydroxynaphthalene-1-carbaldehyde (2c). The reactions were carried out at a 1-to-2 molar ratio of 2 : 1 in boiling glacial acetic acid in the presence of a catalytic amount of sulfuric acid.

N-(4-methoxy-3-nitrobenzyl) derivatives of some nitrogen-containing heterocycles

A number of nitrogen heterocycles reacted with 4-methoxy-3-nitrobenzyl chloride in dimethyl-formamide in the presence of potassium carbonate to give the corresponding N-(4-methoxy-3-nitrobenzyl) derivatives. The reaction of 5-fluoro-1,3-bis(4-methoxy-3-nitrobenzyl)pyrimidine-2,4(1H,3H)-dione with aqueous methylamine afforded N,N′-bis(4-methylamino-3-nitrobenzyl)urea, whereas analogous reaction with 1-(4-methoxy-3-nitrobenzyl)-2-(methylsulfanyl)-1H-benzimidazole resulted in substitution of the methoxy group by methylamino.