V. K. Vasilin

(±)-12b,13-DIHYDROPYRIDO(3",2'':4',5')THIENO- (3',2':4,5)PYRIMIDO(2,1-a)ISOINDOLE-6,8-DIONES: SYNTHESIS AND STEREO STRUCTURE

It has been shown that the reaction of primary 3-aminothieno[2,3-b]pyridine-2-carboxamides with o-formylbenzoic acid gives 12b,13-dihydropyrido[3″,2″:4′,5′]thieno[3′,2′:4,5]pyrimido[2,1-a]iso-indole-6,8-diones. Heterocorrelation NMR spectroscopy and X-ray structural analysis showed that the molecules of the compounds obtained have a linear, double folded stereo structure.

Desulfurization of pyrido[3′,2′:4,5]thieno-[2,3-f]pyrrolo[1,2-a][1,4]diazepines

Pyrrolo[1,2-a][1,4]diazepine derivatives are of interest from the viewpoint of searching for and developing novel substances with a variety of types of biological activity. For many years this fact has stimulated an active search for methods of synthesizing and modifying compounds of this class [1]. It is known [2-4] that the thiophene ring in a thienopyridine fragment can readily undergo desulfurization with opening of the thiophene ring. In this work we report results of a study of the condensed pyrrolodiazepines transformation which contain a thieno[2,3-b]pyridine fragment. Amongst these derivatives we have examined the tetracyclic system of pyridothienopyrrolodiazepines 1a,b prepared by recyclization of N-(5-methylfuran-2-yl)methyl-substituted derivatives of 3-aminothieno[2,3-b]pyridine amides using a known method [5] and we have looked at their reactions in the presence of Raney nickel. It was found that refluxing the diazepines 1a,b in ethanol in the presence of activated Raney nickel gave the desulfurization products, pyrrolodiazepines 2a,b which contain a pyridine ring conjugated to the diazepine fragment and whose structures were proved using NMR and mass spectrometric methods

Synthesis and reactions of 3-cyano-6-methoxymethyl-4-methyl-2(1H)-pyridinethione

Nucleophilic substitution of the chlorine atom in 2-chloro-3-cyano-6-methoxymethyl-4-methylpyridine by mercapto group produces the corresponding 2(1H)-pyridinethione, alkylation of which by halogenated compounds in the presence of KOH proceeds regioselectively to form S-alkyl derivatives. Thorpe—Ziegler cyclization of S-alkyl derivatives, which contain an active methylene group, yields new 3-aminothieno[2,3-b]-pyridines.

Synthesis of substituted 2-alkyl(aryl)thio-3-cyanopyridines and 3-aminothieno[2,3-b]pyridines

The alkylation of 6-methyl-4-methoxymethyl-3-cyano-2-(1H)pyridinethione by halogen derivatives in the presence of KOH proceeds regioselectively with the formation of S-alkyl derivatives. By cathodic electrolysis of the thiols in the presence of 6-methyl-4-methoxymethyl-2-chloro-3-cyanopyridine, 2-arylthiopyridines are obtained. By Thorpe-Ziegler cyclization of 2-alkylthiopyridines having an ctive methylene group, 2-aminothieno[2,3-b]pyridines have been synthesized.

Synthesis of 2-Methyl-1-[(5-methylfuran-2-yl)methyl]- and 2-Methyl-1-[(5-methylpyrrol-2-yl)methyl]-1H-benzimidazoles

A method for the synthesis of 2-methyl-1-[(5-methylfuran-2-yl)methyl]-1H-benzimidazoles based on the intramolecular cyclization of vicinal N-[(5-methylfuran-2-yl)methyl]aminoanilides has been developed. A study was carried out on the protolytic opening of the furan ring leading to the formation of a diketone fragment, which was then used for the formation of N-substituted pyrrole ring by the Paal–Knorr method. The effect of the nature of the amine on the cyclization was demonstrated.

Synthesis of N-alkylated benzo- and pyridothienopyrrolo-[1,2a][1,4]diazepin-6-ones acting as antidotes against the herbicide 2,4-D

We report N-alkylation reactions of pyrrolo[1,2-a][1,4]diazepin-6-ones annulated with a benzene ring or thieno[2,3-b]pyridine system. A range of new N5-substituted pyrrolodiazepines were synthesized, including compounds acting as antidotes against the herbicide 2,4-D.

Synthesis and properties of (thieno[2,3-b]pyridin-3-yl)iminotriphenylphosphoranes. Molecular structure of (2-benzoyl-4-methoxymethyl-6-methylthieno[2,3-b]pyridin-3-yl)iminotriphenylphosphorane

Iminophosphoranes containing a thieno[2,3-b]pyridine fragment were obtained through a sequence of reactions: 1) alkylation of 3-cyano-2(1H)-pyridinethiones in alkaline medium by an α-halocarbonyl compound with subsequent Thorpe-Ziegler cyclization of the resultant 2-thioalkylpyridines to give 3-aminothieno[2,3-b]pyridines, 2) diazotization of the amino group and nucleophilic substitution of the diazonium group by an azido group without isolation of the diazonium salts, and 3) reaction of the 3-azidothieno[2,3-b]pyridines with triphenylphosphine.

Furan ring transformation as key stage in the synthesis of 5H,12H-benzo[4,5]imidazo[1,2-a]pyrrolo[1,2-d]pyrazines

We report the first synthesis of new condensed benzimidazole derivatives – 5H,12H-benzo[4,5]imidazo[1,2-a]pyrrolo[1,2-d]pyrazines, based on furan ring transformation in 1-[(5-alkylfuran-2-yl)methyl]-2-(chloromethyl)benzimidazoles. Two routes are presented for the formation of pyrrolopyrazine system, with different order of steps for the introduction of amino group and opening of the furan ring.

Reaction of vicinal thieno[2,3-b]pyridine aminoamides with Lawesson’s reagent

The reaction of vicinal thieno[2,3-b]pyridine aminoamides with Lawesson’s reagent gave new condensed diazaphosphinine derivatives. The structure of the substituent at the amide nitrogen atom and the reagent ratio were found to affect the direction of this reaction.

Thermolysis of 3-Azido-N-Phenylthieno-[2,3-b]pyridine-2-Carboxamides

Annelated 1,4-diazepines are of interest as they are often compounds possessing different forms of biological and pharmacological activity [1]. Many methods for the synthesis of diazepines have been reported up until now, but the search for novel methods still of interest for scientific community. One of the known methods for closing a diazepine ring is the intramolecular transformation of aromatic azides. The formation of the diazepine ring occurs via photolysis of azides [2] or by an intramolecular cycloaddition of the azide group at a carbon–carbon multiple bond [3-6]. Continuing our study on the synthesis of 1,4-diazepines condensed with a thienopyridine fragment [7] we have developed a method for the preparation of polycyclic 1,4-diazepine derivatives based on the thermal decomposition of thieno[2,3-b]pyridine azides 2a-c. We have selected the N-phenyl-substituted tertiary 3-aminothieno[2,3-b]pyridine-2-carboxamides 1a-c as starting materials and carried out successive diazotization and azide formation reactions to give the corresponding azides 2a-c.