Synthesis of some fused heterocyclic systems and their nucleoside candidates

A series of pyridofuro compounds were synthesized from 4-(4-chlorophenyl)-1,2-dihydro-2-oxo-6-(thiophen-2-yl)pyridine-3-carbonitrile (1) as starting material. Alkylation of 1 with ethyl bromoacetate gave the corresponding ester 2, which was condensed with hydrazine hydrate to afford the corresponding acid hydrazide derivative 3. Thrope-Ziegler cyclization of 2 with sodium methoxide gave furo[2,3-b]pyridine derivative 4, which was reacted with thiosemicarbazide, allyl isothiocyanate, formamide or hydrazine hydrate to give furopyridine derivatives 5–8, respectively. The latter compound 8 was cyclized with acetylacetone or formic acid to give the corresponding compounds 9 and 10, respectively. Furthermore, sulfurization of 1 with P₂S₅ gave the corresponding thioxopyridine 11, which was reacted with glycosyl (or galactosyl) bromide, morpholine or piperidine to give the corresponding thioglycoside 12a,b and Mannich base 14a,b derivatives. The deacetylation of 12a,b gave the corresponding deacetylated thioglycosides 13a,b, respectively. All the newly synthesized compounds were characterized by the elemental analyses and spectroscopic evidences (IR, ¹H- and ¹³C NMR).     

Synthesis of chiral fused heterocyclic compounds containing 1,2,4‐triazole ring

A series of new chiral (S)‐3‐ary1‐6‐pyrrolidin‐2‐yl‐[1,2,4]triazolo[3,4‐b]thiadiazole (II_1‐5), (S)‐1‐(3‐aryl‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazol‐6‐yl)‐ethylamine (II_6‐8) and (S)‐1,2‐bis(3‐aryl‐[1,2,4]triazolo‐[3,4‐b][1,3,4]thiadiazol‐6‐yl)‐ethylamine (II_9‐11) were prepared by the condensation of 3‐aryl‐4‐amino‐5‐mercapto‐1,2,4‐triazoles with different L‐amino acids in the presence of phosphorus oxychloride and evaluated for their antibacterial activity.     

Synthesis of some novel heterocyclic dyes derived from pyrazole derivatives

Diazotized aryl amines were coupled with 3-substituted 5-amino pyrazoles to produce a series of novel 3-substituted 5-amino-4-arylazopyrazoles. Also, 3-substituted 5-amino-pyrazoles were diazotized and coupled with different phenols to give the corresponding novel 3-substituted 5-aryl azo pyrazoles. These dyes were characterized by elemental analysis and spectral data, applied to different types of fibres (wool, polyester and a blend of wool/polyester as disperse dyes) and their fastness properties were evaluated.     

Synthesis of some heterocyclic compounds derived from indole as antimicrobial agents

Recently, indoles are considered interesting heterocyclic compounds due to their wide range of biological activities such as antimicrobial activity. Herein, some new indole derivatives containing heterocyclic moieties were synthesized using 3-chloro-1H-Indole-2-carbaldehyde (1) as a starting material, then allowed to react with compounds containing active methylene under Knoevenagel condensation and afforded the corresponding compounds (2, 3, 9). Also, the compound (1) when allowed to react with hydrazine derivatives gave the corresponding thiosemiccarbazone, semicarbazone, and hydrazone derivatives (4, 5, 6). Reaction of thiosemicarbazone derivatives with α-halognated carbonyl compounds gave the thiazolyl indole derivatives (10, 12a–b). Cyclic chalcones (11a–c) were obtained when compound (10) reacted with different aromatic aldehydes. The structures of all new synthesized compounds were confirmed on the basis of spectral analysis, IR, 1H NMR, 13C NMR, and MS spectroscopy. All synthesized compounds were evaluated for their antimicrobial activity. Compounds (2, 5, 7, 8, 11a, 12a) showed high antibacterial activity and compounds (3, 6, 9, 10, 11a, 12a) showed high antifungal activity.     

Synthesis of fused heterocyclic compounds on the basis of 2-thioxo-1,3-thiazolidin-4-ones

Methods for the preparation of various fused heterocyclic systems having thiazolothiadiazole, furothiazole, pyrazolothiazole, thiazolopyridine, pyranothiazole, and chromenopyranothiazole skeletons were developed using 2-thioxo-1,3-thiazolidin-4-ones as initial compounds.     

Research on heterocyclic compounds. XX. Synthesis of trifluoromethyl derivatives of fused imidazole systems

A series of heterocyclic compounds having an imidazole ring fused with another ring with a bridgehead nitrogen atom and bearing a trifluoromethyl moiety was synthesized by reaction of 3-bromo-1,1,1-trifluoroacetone with various heteroarylamines. In some cases, an intermediate compound obtained together with the required product was isolated and its structure was elucidated: e.g., starting from 2-aminopyridine we have obtained 2-trifluoromethylimidazo[1,2-a]pyridine and 2-hydroxy-2-trifluoromethyl-2,3-dihydro-1H-imidazo [1,2-a]pyridinium bromide. Such results confirmed the mechanism previously proposed for this reaction.     

Nitroalkyl derivatives of some heterocyclic compounds

The 2-(-methyl--nitrobutyl) derivatives of 2-imidazoline, benzimidazole, and benzoxazole and 2,4,6-tris-(-methyl--nitrobutyl)1,3,5-triazine have been synthesized. The nitroalkyl derivatives of 2-imidazoline and benzimidazole have been reduced to the corresponding 2-aminoalkyl derivatives.     

The analysis of some heterocyclic compounds

The mass spectra of some relatively simple sulphur compounds have been obtained. Comments upon the McLafferty rearrangement are reported.     

缩杂环卓酮化合物的合成

本文报道Friedlaender反应在卓酮化学中的应用, 合成了喹啉基取代的卓酮化合物。     

异色满酮-4及其衍生物的合成IX异香豆素并杂环化合物的合成

本文通过3, 4-二氢异苯并吡喃酮-4和其β-二酮衍生物的缩合反应, 合成出3, 4-二氢异苯并吡喃并吲哚、并喹啉、并吡唑和并嘧啶类化合物, 并进一步氧化成标题化合物。所合成的新化合物均经核磁共振光谱红外光谱及元素分析证明其分子结构。     

Synthesis of novel heterocyclic fused 1,3-diazabuta-1,3-dienes and accompanying rearrangements in their cycloaddition reactions with ketenes: synthesis of heterocyclic fused pyrimidinone derivatives

The reactions of 1,3-diazabuta-1,3-dienes 1 with 2-aminothiophenol have been shown to result in excellent yields of N-benzothiazol-2-yl-N′-aryl benzamidines 2. Their regioselective [4+2] cycloadditions with various ketenes are shown to yield novel benzothiazolo pyrimidinones 4. A similar and convenient protocol for the synthesis of bisthiosubstituted 1,3-diazabuta-1,3-dienes 8 and 9 and interesting rearrangements accompanying their [4+2] cycloadditions with a number of ketenes are described.     

Synthesis of some heterocyclic spirocompounds

1,3-Dipolar cycloaddition reactions of methylenepyrrolidinones with nitrilimines or nitrones resulted in regio and stereoselective formation of respective spiropyrazolines or spiroisovazolidines.Department of Organic Chemistry, Slovak Technical University, Radlinského 9, 81237 Bratislava, Slovak Republic. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1353–1355, October, 1995. Original article submitted August 24, 1995.     

Synthesis of some fused triazoloquinolines

The reaction of 3 -amino-1,2,4-triazolo[4,3-a]quinoline ( II ) with diethyl ethoxymethylenemalonate and ethyl acetoacetate/ethyl trifluoroacetoacetate afforded 10-carboethoxy-9-oxo-9H-pyrimido[1′,2′:1,5][1,2,4]triazolo-[4,3-a]quinoline ( III ) and 11-methyl/trifluoromethyl-9-oxo-9H-pyrimido[1′,2′:1,5][1,2,4]triazolo[4,3-a]quinoline ( IV/V ) respectively. 2-Chloropyridine-3-carboxylic acid chloride reacted with II to yield 5-oxo-5H-pyrido-[3″,2″:5′,6′]pyrimido[1′,2′:1,5][1,2,4]triazolo[4,3-a]quinoline ( VII ), a new ring system.     

Synthesis and antitumor evaluation of some new derivatives and fused heterocyclic compounds derived from thieno[2,3-b]pyridine: Part 2

As a continuation of our research on developing anticancer agents and based on the proven proprieties of thieno[2,3-b]pyridines as anticancer, we have designed to synthesize novel thieno[2,3-b]pyridine derivatives that incorporate different biologically active heterocycles through various chemical reactions. All of the newly obtained compounds, compared with the standard anticancer drug (doxorubicin), were screened in vitro for their antitumor activity against hepatocellular carcinoma (HepG-2) and human breast cancer (MCF-7) cell lines. The results revealed that compounds 3 , 7 , 12 , and 19 were found to be the most potent against both HepG-2 and MCF-7 cell lines exhibiting IC₅₀ values ranging from 3.67 to 11.50 and 5.13 to 11.80 μg/mL, respectively, among which compound 7 has a more potent activity than the reference drug doxorubicin against HepG-2 cell line, showing IC₅₀ value of 3.67 μg/mL (doxorubicin 4.65 μg/mL).     

Synthesis and antitumor evaluation of some new derivatives and fused heterocyclic compounds derived from thieno[2,3‐b]pyridine

On the basis of the proven activity of thieno[2,3‐b]pyridines as anticancer, we have designed to synthesize a novel several heterocyclic compounds utilizing thieno[2,3‐b]pyridine as a skeleton through various chemical reactions. The synthesized compounds bear rings that are either directly attached to the thieno[2,3‐b]pyridine as in compounds 4 to 6 and 9 or connected through an amide bridge as compounds 2 , 3a ‐ b , 7 , and 8 . As well as, compounds 10 , 12 to 28 , 30 , 31 , and 33 to 36 bear fused rings to the thieno[2,3‐b]pyridine backbone. The newly synthesized compounds were screened for their antiproliferative activity in vitro against hepatocellular carcinoma (HepG‐2) and breast cancer (MCF‐7) compared with the standard drug (doxorubicin). Compounds 3b , 4 , 6 , 22 , and 28 exhibited promising growth inhibitory effect toward both HepG‐2 and MCF‐7 cell lines with IC₅₀ values ranging from 5.88 to 11.70 μg/mL and 9.64 to 15.10 μg/mL, respectively.     

Synthesis and NMR spectral assignments of novel nitrogen and sulfur heterocyclic compounds

Synthesis and NMR spectral studies of multidentate N and S heterocycles, 1,3,5-tris(N-methylbenzimidazolyl)benzene, 1,3,5-tris(benzimidazolyl)benzene,1,3,5-tris(benzothiazolyl) benzene, 2,2'-bipyridine 3,3'-bis(benzothiazolyl)benzene and 1,2,4,5-tetrakis(benzothiazolyl) benzene have been carried out. 2D (1)H-(1)H PFG-COSY as well as (1)H-(13)C single and multiple bond correlated (2D GRASP-HSQC and GRASP-HMBC) experiments have been employed to characterize the compounds. 1D NOE experiments have been useful in understanding the structure of 1,3,5-tris(N-methylenzimidazolyl)benzene.     

Synthesis and reactions of heterocyclic compounds

5-Azido-2-methylbenzthiazole, 6-azido-1, 2-dimethyl-, and 5-azido-2-methyl-1-phenylbenzimidazoles were prepared. By the reactions of these azides with alkyl halides the quaternary slats based on the cyanine dyes were obtained.     

Soluble polyelectrolytes based on some heterocyclic compounds

With the purpose of synthesizing the new types of soluble polyelectrolytes for special purposes radical polymerization and copolymerization of a number of heterocyclic compounds in solvents of different types with wide interval of pH medium was investigated. Interrelationships between reaction ability of the studied monomers and dielectric polarization of the media was established. An essential influence of water and pH medium on the polymerization rate and molecular weight of the synthesized polymers is found. The obtained effects are described on the basis of ionized monomers. The possibility to synthesize stereoisomeric polymers based on individual 3-buten-1-ynylpiperidinol isomers was shown. Some perspective ways of their practical application are given.