Samvel N. Sirakanyan

Synthesis and Neurotropic Activity of 8-Amino Derivatives of Condensed Thieno[3,2-d]- and Furo[3,2-d]Pyrimidines

New derivatives of pyrano[4″,3″:4′,5′]pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidines based on 3-chloro derivatives of pyrano[3,4-c]pyridines and pyrano[4″,3″:4′,5′]pyrido[3′,2′:4,5]furo[3,2-d]pyrimidines based on previously prepared 8-chloro derivatives were synthesized. Studies of the biological activity of the synthesized compounds showed that several of them exhibited neurotropic properties.

Synthesis, transformations and biological properties of furo[2,3-b]pyridines

Data on furo[2,3-b]pyridines published in the last 15 years are integrated and analyzed for the first time. Information on the methods of synthesis, chemical transformations and biological action of these systems is described systematically. Particular attention is paid to the preparation and study of properties of polycondensed derivatives as the most promising and rapidly developing line of research of furo[2,3-b]pyridine chemistry. The biological properties of this class of compounds are discussed, and examples of furo[2,3-b]pyridines that exhibit high biological activities are given. The bibliography includes 88 references.

Synthesis and Anticonvulsant Activity of 7(8)-Amino Derivatives of Condensed Thieno[3,2- d ]Pyrimidines

Methods for synthesizing novel amino derivatives of cyclopenta[4′,5′]pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidines and tetrahydropyrimido[4′,5′:4,5]thieno[2,3-c]isoquinoline from 3-chloro derivatives of alicyclo[c]pyridines were elaborated. Studies of the anticonvulsant activity of the synthesized compounds showed that they exhibited pronounced anticonvulsant activity and low toxicity.

Synthesis and Neurotropic Activity of Triazolo[3,4-a]-and Triazolo[5,1-a][2,7]Naphthyridines

Methods for synthesizing new substituted 7,8,9,10-tetrahydro[1,2,4]triazolo[3,4-a][2,7]naphthyridines from -hydrazino-7-isopropyl-3-chloro-5,6,7,8-tetrahydro[2,7]naphthyridine-4-carbonitrile were developed. It was shown that heating triazolo[3,4-a][2,7]-naphthyridines in an excess of amines produced isomeric triazolo[5,1-a][2,7]naphthyridine derivatives. These isomers were interconverted using a Dimroth rearrangement. The neurotropic activity of the synthesized compounds was studied.

Pyridofuropyrrolo[1,2-a]pyrimidines and pyridofuropyrimido[1,2-a]azepines: new chemical entities (NCE) with anticonvulsive and psychotropic properties

Herein we report the synthesis of several new condensed furo[2,3-b]pyridines 3 from the 3-oxo derivatives of cyclopenta[c]pyridine, of 5,6,7,8-tetrahydroisoquinoline and of pyrano[3,4-c]pyridine 1. The obtained furo[2,3-b]pyridines 3 were used as starting materials for the synthesis of pyridofuropyrrolo[1,2-a]pyrimidines 4 and of pyridofuropyrimido[1,2-a]azepines 5. Interestingly enough, derivatives of pyridofuropyrimido[1,2-a]azepines 5 exhibited anticonvulsant activity significantly better than that of the commercial drug ethosuximide (zarontin). Some of them showed a sedative effect, unlike ethosuximide.

Synthesis of New Heterocyclic Systems on the Basis of 7-Benzyl-3-chloro-1-(morpholin-4-yl)-5,6,7,8-tetrahydro-2,7-naphthiridine-4-carbonitrile

Methods have been developed for the synthesis of new 8-amino-3-benzyl-5-(morpholin-4-yl)-1,2,3,4-tetrahydropyrimido[4′,5′: 4,5]thieno[2,3-c][2,7]naphthyridine starting from 7-benzyl-3-chloro-1-(morpholin-4-yl)-5,6,7,8-tetrahydro-2,7-naphthyridine-4-carbonitrile. 8-Hydrazinyl-3-benzyl-5-(morpholin-4-yl)-1,2,3,4-tetrahydropyrimido[4′,5′: 4,5]thieno[2,3-c][2,7]naphthyridine has been converted to isomeric pentacyclic structures with a triazole ring fused through the [c] side of the pyrimidine ring, and their Dimroth rearrangement has been accomplished in both acidic and basic media. New heterocyclic systems containing pyrrolo[1,2-a]pyrimidinone and pyrimido[1,2-a]azepinone fragments were obtained on the basis of the thieno-[2,3-c][2,7]naphthyridine derivative.

New Synthesis of Pyrano[4,3-d]pyrazolo[3,4-b]pyridines

A new efficient method has been developed for the synthesis of highly biologically active pyrano-[4,3-d]pyrazolo[3,4-b]pyridines on the basis of Smiles rearrangement of ethyl [(8-alkyl(aryl)-5-cyano-3,3-dimethyl-3,4-dihydro-1H-pyrano[3,4-c]pyridin-6-yl)oxy]acetates. Intermediate acetohydrazides have also been isolated. The proposed procedure is advantageous due to the possibility of avoiding experimentally difficult chlorination stage.

New efficient synthesis of 6-aminopyrano[3,4- c ]pyridines via Smiles type rearrangement

A new efficient procedure has been developed for the synthesis of 6-aminopyrano[3,4-c]pyridines via Smiles type rearrangement. The procedure is characterized by improved overall yield and avoidance of experimentally difficult chlorination step.

Synthesis and neurotropic activity of new derivatives of piperazino-substituted pyrano[3,4-c]pyridines

Methods for the synthesis of new derivatives of substituted piperazines were developed. Syntheses were based on chloro derivatives of pyrano[3,4-c]pyridines. The anticonvulsive and predicted tranquillizer activities of the compounds synthesized here were studied. Compounds with neurotropic – anticonvulsive, antiamnestic, and sedative – properties were identified.