Three-component cyclization of hydroxylamino-substituted quinoline with reactive methylene compounds and formaldehyde: new method for the synthesis of 7-(isoxazolidin-2-yl)-6-fluoroquinolones

A one-step procedure was developed for the synthesis of new 6-fluoro-7-(isoxazolidin-2-yl)-4-oxo-1,4-dihydroquinolines. The procedure is based on the 1,3-dipolar cycloaddition of the azomethine oxide and 1,1-disubstituted alkenes, which are generated in situ from 6-fluoro-7-hydroxylamino-4-oxo-1,4-dihydroquinoline-3-carboxylic acid and CH-active compounds (dialkyl malonates, ethyl acetoacetate), respectively, in the presence of formaldehyde at 100—120 °C.     

A new synthetic route to aminothiazolinones

Novel 2-(5-R-1,3,4-thiadiazol-2-yl)aminothiazolin-4-ones 6a—h and 2-imino-3-(5-R-1,3,4-thiadiazol-2-yl)thiazolidin-4-ones 7a—h were prepared by treating N-(5-R-1,3,4-thiadiazol-2-yl)thioureas 4a—h with chloroacetic acid on various solid supports under microwave irradiation. Tautomeric mixtures of compounds 6a—h and 7a—h were obtained in all cases. In alkaline and neutral media, compounds 6a—h were the major products, while in acid media, 7a—h were the major products.     

Discovery of New Pyrazolopyridine,Furopyridine, and Pyridine Derivatives as CDK2 Inhibitors: Design,Synthesis, Docking Studies,and Anti-Proliferative Activity

New pyridine, pyrazoloyridine, and furopyridine derivatives substituted with naphthyl and thienyl moieties were designed and synthesized starting from 6-(naphthalen-2-yl)-2-oxo-4-(thiophen-2-yl)-1,2-dihydropyridine-3-carbonitrile (1). The chloro, methoxy, cholroacetoxy, imidazolyl, azide, and arylamino derivatives were prepared to obtain the pyridine-⁻C² functionalized derivatives. The derived pyrazolpyridine-N-glycosides were synthesized via heterocyclization of the C²-thioxopyridine derivative followed by glycosylation using glucose and galactose. The furopyridine derivative 14 and the tricyclic pyrido[3′,2′:4,5]furo[3,2-d]pyrimidine 15 were prepared via heterocyclization of the ester derivative followed by a reaction with formamide. The newly synthesized compounds were evaluated for their ability to in vitro inhibit the CDK2 enzyme. In addition, the cytotoxicity of the compounds was tested against four different human cancer cell lines (HCT-116, MCF-7, HepG2, and A549). The CDK2/cyclin A2 enzyme inhibitory results revealed that pyridone 1, 2-chloro-6-(naphthalen-2-yl)-4-(thiophen-2-yl)nicotinonitrile (4), 6-(naphthalen-2-yl)-4-(thiophen-2-yl)-1H-pyrazolo[3,4-b]pyridin-3-amine (8), S-(3-cyano-6-(naphthaen-2-yl)-4-(thiophen-2-yl)pyridin-2-yl) 2-chloroethanethioate (11), and ethyl 3-amino-6-(naphthalen-2-yl)-4-(thiophen-2-yl)furo[2,3-b]pyridine-2-carboxylate (14) are among the most active inhibitors with IC₅₀ values of 0.57, 0.24, 0.65, 0.50, and 0.93 µM, respectively, compared to roscovitine (IC₅₀ 0.394 μM). Most compounds showed significant inhibition on different human cancer cell lines (HCT-116, MCF-7, HepG2, and A549) with IC₅₀ ranges of 31.3–49.0, 19.3–55.5, 22.7–44.8, and 36.8–70.7 μM, respectively compared to doxorubicin (IC₅₀ 40.0, 64.8, 24.7 and 58.1 µM, respectively). Furthermore, a molecular docking study suggests that most of the target compounds have a similar binding mode as a reference compound in the active site of the CDK2 enzyme. The structural requirements controlling the CDK2 inhibitory activity were determined through the generation of a statistically significant 2D-QSAR model.     

4-Hydroxy-2-quinolones. 107. Reaction of triethyl methanetricarboxylate with indoline

The first stage of the reaction of triethyl methanetricarboxylate with indoline is the formation of the diethyl ester of 2-(indoline-1-carbonyl)malonic acid, which then, depending on the conditions selected, may be converted into the ethyl ester of 2-(indoline-1-carbonyl)-3-(indolin-1-yl)-3-oxopropionic acid, methanetri-N-(indolin-1-yl)carboxamide, or the ethyl ester or (indolin-1-yl)amide of 1-hydroxy-3-oxo-5,6-dihydro-3H-pyrrolo[3,2,1-ij]quinoline-2-carboxylic acid. __________ Translated From Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1191–1197, August, 2006.     

Boron chelate complexes with 4-[N-(R-pyrid-2-yl)carbamoyl]-3-amino-2-cyanobuten-2-ic acid esters (codimers of N-(R-pyrid-2-yl)amides and the ethyl ester of cyanoacetic acid)

Mono- and binuclear boron chelates have been synthesized by the action of butylthiodibutylborane on the ethyl esters of 4-[N-(R-pyrid-2-yl)carbamoyl]-3-amino-2-cyanobuten-2-ic acids (codimers of N-(R-pyrid-2-yl) amides and the ethyl ester of cyanoacetic acid). Complexes of this type can exist in solution in the form of two tautomers: acetamide acid derivatives or the corresponding ketene N,O-acetals.N. D. Zelinski Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2162–2170, September, 1992.     

From 4,5,6,7-tetrahydroindoles to 3- or 5-(4,5,6,7-tetrahydroindol-2-yl)isoxazoles in two steps: a regioselective switch between 3- and 5-isomers

(4,5,6,7-Tetrahydroindol-2-yl)alkynes, synthesized by cross-coupling of 4,5,6,7-tetrahydroindoles with aroyl(hetaroyl)bromoalkynes or ethyl bromopropynoate in the presence of K₂CO₃, regioselectively cyclize with hydroxylamine to either 3- or 5-(4,5,6,7-tetrahydroindol-2-yl)isoxazoles depending on the acidity of the reaction mixture: in the presence of acetic acid 3-isomers are formed (ca. 100% selectivity), while under neutral conditions the reaction is switched to 5-isomers (94–97% selectivity).     

Kine-substitution in the N-[ω-(5-bromouracil-1-yl)alkyl]alkylamine series

In the reaction of N-[2-(5-bromouracil-1-yl)ethyl]alkylamines with alkylamines at 40 °C kine-substitution takes place with the formation of N-[2-(6-alkylamino-uracil-1-yl)ethyl]alkylamines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1260–1261, September, 1984.     

Synthesis of 2-iminoimidazolidin-4-one derivatives by cyclization of 2-aryl-1-(4,6-dimethylpyrimidin-2-yl)guanidines with ethyl bromoacetate, dimethyl acetylenedicarboxylate, and maleic anhydride

Derivatives of 2-iminoimidazolidin-4-one, (E)-methyl (2-imino-5-oxoimidazolidin-4-ylidene)acetate, and (2-imino-5-oxo-imidazolidin-4-yl)acetic acid were synthesized by the cyclization of 2-aryl-1-(4,6-dimethylpyrimidin-2-yl)guanidines with ethyl bromoacetate, dimethyl acetylenedicarboxylate, and maleic anhydride, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1372–1378, July, 2007.     

Nitrogen and sulfur containing heterocycles. 50. Synthesis and reactions of 6-oxopyrimido[4,5-b][1,4]thiazine-7-carboxylic acid derivatives

Reaction of 5-amino-6 mercaptopyrimidines with diethyl bromomalonate gave ethyl 6-oxopyrimido-[4,5-b][1,4]thiazine-7-carboxylates, from which there was synthesized a series of derivatives at the carboxyl group (amides, hydrazides, and, from the latter, urethanes). Desulfurization of the 6-oxopyrimidothiazine-7-carboxylic acid esters gave N-(pyrimidin-5-yl)monoamides of ethyl malonate.For communication 49 see [1].Center for Chemistry of Drugs—All-Russian Research Chemical-Pharmaceutical Institute, Moscow 119021, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 822–828, June, 1999.     

Simultaneous Calorimetric and Potentiometric Investigations on Some Uncatalyzed Bromate Oscillators (UBOs)

Simultaneous calorimetric and potentiometric/thermometric measurements were performed on three uncatalyzed bromate oscillators (UBOs) showing distinct temporal structures. The following UBOs were chosen: a) the gallic acid (3,4,5-trihydroxy benzoic acid)—bromate; b) the 1-hydroxy-4-[(1-hydroxy-2-methylamino)ethyl] benzene (HME)—bromate; and c) the 1,4-cyclohexanedione (CHD)—bromate system. Their oscillating reactions were monitored by an isoperibolic batch calorimeter of the Calvet-type at 20°C and with a quasi-adiabatic Dewar setup at room temperature, and in addition by platinum/calomel potentiometry and thermometry. Shape of the calorimetric curves, number and duration of the oscillations and their frequencies varied considerably between these three UBOs. The underlying chemical reaction schemes are discussed in connection with the energetic background.This revised version was published online in November 2005 with corrections to the Cover Date.     

Activated nitriles in heterocyclic synthesis: Synthesis of 6-thiophen-2-yl and 6-furan-2-ylthiazolo[2,3—a]pyridine derivatives

A variety of new 6-thiophen-2-yl and 6-furan-2-ylthiazolo[2,3—a]pyridine derivatives could be prepared via the reaction of 2-functionally substituted methyl-2-thiazolin-4-one with cyanomethylenethiophen-2-yl and cyanomethylenefuran-2-yl derivatives. The structure of the reaction products was established based on spectral data.

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Aktivierte Nitrile in der Heterocyclen-Synthese: Die Synthese von 6-Thiophen-2-yl-und 6-Furan-2-yl-thiazolo[2,3—a]pyridin-Derivaten

Zusammenfassung Es konnte eine Reihe neuer 6-Thiophen-2-yl- und 6-Furan-2-yl-thiazolo-[2,3—a]pyridine über die Reaktion von 2-funktionell-substituierten Methyl-2-thiazolin-4-onen mit Cyanomethylenthiphen-2-yl bzw. Cyanomethylenfuran-2-yl-Derivaten hergestellt werden. Die Struktur der Reaktionsprodukte wurde mit spektroskopischen Methoden ermittelt.

     

Synthesis and reactions of 3-(3-ethoxycarbonyl-1-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-4-yl)propenic acid

The reaction of ethyl 4-formyl-1-phenyl-1H-pyrazole-3-carboxylate with the malonic acid led to the formation (2E)-3-(3-ethoxycarbonyl-1-phenyl-1H-pyrazol-4-yl)propenic acid. In reactions of this acid chloride with 4-amino-5-aryl(hetaryl)-4H-1,2,4-triazole-3-thiols were obtained ethyl 4-[(E)-2-{3-aryl(hetaryl)[1,2,4]triazolo[3,4-b][1,3,4]thiadiazol-6-yl}ethenyl]-1-phenyl-1H-pyrazoe-3-carboxylates, with 5-aryltetrazoles, ethyl 4-[(E)-2-(5-aryl-1,3,4-oxadiazol-2-yl)-ethenyl]-1-phenyl-1H-pyrazole-3-carboxylates, with 1-(2-hydroxy-3,5-dimethylphenyl) followed by the Baker-Venkataraman rearrangement and the cyclization, ethyl 4-[(E)-2-(6,8-dimethyl-4-oxo-4Hchromen-2-yl)ethenyl]-1-phenyl-1H-pyrazole-3-carboxylate.     

Synthesis of new condensed heterocyclic systems

Two new diamines — [1,3-bis(5-phenyl-1,2,4-triazol-3-yl)-4,6-diamino]benzene and [1,3-di-(2-benzimldazolyl)-4,6-diamino]benzene — were synthesized from 4,6-dinitroisophthalic acid. Newheterocyclic systems — 3,5,9,11-tetraphenyl[benzo[1,2-a; 4,5-a]bis(1,2,4-triazolo[4,3-c]pyrimidine)] and 2,16-diphenyl[benzo[1,2-a;4,5-a']bis(pyrimido[1,6-a]benzimidazole)]—were obtained by reaction of the diamines with benzoyl chloride and subsequent cyclization.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1274–1277, September, 1977.     

A new selective reagent for the spectrofluorometric determination of beryllium

The fluorescence properties of the beryllium and aluminum complexes with 2, 4-dioxo-4-(4-hydroxy-6-methyl-2-pyrone-3-yl) butyric acid ethyl ester (Ligand) were studied and optimal conditions for their fluorometric determination were established. Beryllium can be determined in the linearity range of 0.5–2.0 μg/ml and aluminum 0.5–1.5 μg/ml. The effect of diverse ions on the determination of beryllium is discussed.A simple procedure for the fluorometric determination of beryllium in human blood plasma in the concentration range of 5–50 μg Be/ml is described.     

Synthesis of 2-[2-(5-phenyl-1,2,4-oxadiazol-3-yl)-ethyl]benzimidazole and its x-ray analysis

Cyclization of O-benzoyl-2-(benzimidazol-1-yl)propioamidoxime under different temperature conditions gave 2-[2-(5-phenyl-1,2,4-oxadiazol-3-yl)ethyl]benzimidazole whose structure has been determined by X-ray analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1057–1061, July, 2006.     

Synthesis of Novel 2-(Pyridin-2-yl) Pyrimidine Derivatives and Study of Their Anti-Fibrosis Activity

A pyrimidine moiety exhibiting a wide range of pharmacological activities has been employed in the design of privileged structures in medicinal chemistry. To prepare libraries of novel heterocyclic compounds with potential biological activities, a series of novel 2-(pyridin-2-yl) pyrimidine derivatives were designed, synthesized and their biological activities were evaluated against immortalized rat hepatic stellate cells (HSC-T6). Fourteen compounds were found to present better anti-fibrotic activities than Pirfenidone and Bipy55′DC. Among them, compounds ethyl 6-(5-(p-tolylcarbamoyl)pyrimidin-2-yl)nicotinate (12m) and ethyl 6-(5-((3,4-difluorophenyl)carbamoyl)pyrimidin-2-yl)nicotinate (12q) show the best activities with IC₅₀ values of 45.69 μM and 45.81 μM, respectively. Furthermore, the study of anti-fibrosis activity was evaluated by Picro-Sirius red staining, hydroxyproline assay and ELISA detection of Collagen type I alpha 1 (COL1A1) protein expression. Our study showed that compounds 12m and 12q effectively inhibited the expression of collagen, and the content of hydroxyproline in cell culture medium in vitro, indicating that compounds 12m and 12q might be developed the novel anti-fibrotic drugs.     

Synthesis of 2,5-bis(2-aminothiazol-5-yl)-3,6-dichloro-1,4-benzoquinones

A series of 2-(2-aminothiazol-5-yl)-3,6-dichloro-5-diethylaminoethenyl-1,4-benzoquinones was synthesized from 2-(2-aminothiazol-5-yl)-3,5,6-trichloro-1,4-benzoquinones using acetaldehyde and diethylamine in toluene solution. Refluxing these compounds with substituted thioureas in acetonitrile in the presence of hydrochloric acid gives the corresponding 2,5-bis(2-aminothiazol-5-yl)-3,6-dichlorohydroquinones which can be oxidized to the target products with ferric chloride in aqueous DMF.Riga Technical University, Riga LV-1048, LatviaTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 835–839, June, 2000     

The addition reaction of acrylonitrile and methylacrylate toN-(5R-1,3,4-thiadiazol-2-yl)dithiocarbamates

A new type of dithiocarbamic acid derivatives,S-(2-X-ethyI) ethers ofN-(5R-1,3,4-thiadiazol-2-yl)-dithiocarbamic acids (X = CN, COOMe), has been synthesized by the reaction of sodiumN-(1,3,4-thiadiazol-2-yl) dithiocarbamates with acrylonitrile and methylacrylate.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 749–750, April, 1994.     

Carboxylic Acids from <Emphasis Type="Italic">Phyllanthus urinaria</Emphasis>

Five compounds, terephthalic acid mono-[2-(4-carboxy-phenoxycarbonyl)-vinyl] ester (1), (E)-3-(5′-hydroperoxy-2,2′-dihydroxy[1,1′-biphenyl]-4-yl)-2-propenoic acid (2), 3,4,5-trihydroxybenzoic acid (3), succinic acid (or butanedioic acid) (4), and 2,3,4,5,6-pentahydroxybenzoic acid (5), were isolated from Phyllanthus urinaria. The structures of these compounds were elucidated by means of spectral techniques including IR, MS, and 1D/2D NMR. 1 and 2 are new compounds.__________Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 14–17, January–February, 2005.