Synthesis of derivatives of a new heterocyclic system pyrazolo[3,4-b]pyrido[1′,2′: 1,2]imidazo[4,5-d]pyridine

1-[4-Aminoarylpyrazolo[3,4-b]pyridin-5-yl]pyridinium chlorides undergo cyclization under reflux in tert-butanol in the presence of an excess of potassium tert-butoxide to form tetracyclic derivatives of pyrazolo[3,4-b]pyrido[1′,2′:1,2]imidazo[4,5-d]pyridine. The reaction scheme of the processes is proposed. The structures of the reaction products were confirmed by physicochemical methods. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 710–714, April, 2006.     

Synthesis and functionalization of 7-hydroxyanthra[2,1-<Emphasis Type="Italic">b</Emphasis>]benzo[<Emphasis Type="Italic">d</Emphasis>]furan-8,13-diones

The diazotization of 1-amino-2-aryloxy-4-hydroxy-9,10-anthraquinones in various solvents and subsequent heating of the diazotization products lead to 7-hydroxyanthra[2,1-b]benzo[d]furan-8,13-diones. When consecutively treated with benzenesulfonyl chloride and amines, the products form 7-aminoanthra[2,1-b]benzo[d]furan-8,13-diones.     

Heterocyclic analogs of 5,12-naphthacenequinone 8.* Synthesis of furano-anthraquinones

During the condensation of 2,3-dichloroquinizarine with methyl pivaloylacetate in the presence of potassium carbonate in dimethyl sulfoxide the main reaction products are derivatives of angular 3-pivaloylanthra[1,2-b]furan-2,6,11(3H)-trione (about 70%) and anthra[2,1-d][1,3]dioxole-6,11-dione (15%), whereas the yield of the targeted linear methyl 2-tert-butyl-4,11-dihydroxyanthra[2,3-b]furan-5,10-dione-3-carboxylate is only 2%. Methods are developed for modification of the obtained 3-pivaloylanthra[1,2-b]furan-2,6,11(3H)-trione, making it possible to use it for the synthesis of the tert-butyl derivatives of linear anthra[2,3-b]furan-5,10-dione or angular anthra[1,2-b]furan-6,11-dione. *For Communication 7 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 191–202, February, 2009.     

Cross-condensation of derivatives of cyanoacetic acid and carbonyl compounds. 2. One-pot synthesis of substituted 2-amino-7-methyl-5-oxo-4,5-dihydropyrano[4,3-b]pyrans in ethanol and ionic liquid [bmim][PF6]

The three-component reaction of 4-hydroxy-6-methylpyran-2(2H)-one with cyanoacetic acid derivatives and carbonyl compounds in EtOH or in the ionic liquid, viz., 1-butyl-3-methylimidazolinium hexafluorophosphate ([bmim][PF₆]), affords substituted 2-amino-7-methyl-5-oxo-4,5-dihydropyrano[4,3-b]pyrans. The yield of substituted pyrano[4,3-b]pyrans in [bmim][PF₆] is by 10—14% higher than that in EtOH.     

Saturated heterocycles, 75. Preparation of tetracyclic thiophene derivatives with bridgehead nitrogen. Synthesis of polymethylenethieno[2,3—d]dihydropyrrolo-, tetrahydropyrido- and tetrahydroazepino[1,2—a]pyrimidin-4-ones and -4-thiones

The following tetracyclic ring systems and their derivatives have been synthesized for pharmacological investigations: Trimethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and -4-thione (1 a, 5 a); Tetramethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and -4-thione (1 b, 1 j, 5 b); Pentamethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and-4-thione (1 c, 5 c); Trimethylenethieno[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one and -4-thione (1 d, 5 d); Tetramethylenethieno[2,3—d]tetrahydropyrido[1,2,—a]pyrimidin-4-one and -4-thione (1 e, 5 e); Pentamethylenethieno[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one and -4-thione (1 f, 5 f); Trimethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one and -4-thione (1 g, 5 g); Tetramethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-on and -4-thione (1 h, 5 h); Pentamethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one and -4-thione (1 i, 5 i); Tentamethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one (7 b); Pentamethylenethieno-[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one (7 c).Compounds1 a–i were synthesized from 2-amino-3-ethoxycarbonyl-4,5-polymethylenethiophene2 a–c with the corresponding lactim ethers (3 a–c) in chlorobenzene in the presence of polyphosphoric acid (PPA). Compounds7 b and7 c were obtained in the reaction of -amino acid esters2 b and2 c with 2-bromopyridine (6). The thione derivatives (5 a–i) were prepared from compounds1 a–i with phosphorus(V) sulphide.Part 74:Szabó J, Fodor L, Szcs E, Bernáth G, Sohár P (1984) Pharmazie 39: 347.     

Photochemical synthesis of 2-amino-1-hydroxy-9,10-anthraquinone-9-alkyl(aryl)imines

Irradiation of a mixture of 1-aryloxy-2-amino-9,10-anthraquinone and amines in benzene results in formation of the derivatives of 2-amino-1-hydroxy-9,10-anthraquinone-9-alkyl(aryl)imines in a high yield. 2-Amino-1-hydroxy-9,10-anthraquinone-9-aikylimines were shown by¹³C and¹⁵N NMR to exist predominantly in the enaminoquinoid form whereas 2-amino-1-hydroxy-9,10-anthraquinone-9-arylimines exist in the oxyimine form. Sunlight irradiation of the derivatives of 2-benzoylamino-9,10-anthraqumone-9-alkylimines results in formation of the photocyclization products — 4-benzoylaminoanthra-[9,1-d,e]-1,3-oxasinones-7.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 940–944, May, 1993.     

Synthesis of new thiazolo[2,3-b]pyrimidine derivatives of pharmaceutical interest

2H-5-Amino-6-cyano-3,7-dioxothiazolo[2,3-b]pyrimidine was subjected to ring formation affording thiazolo[2,3-b]pyrimidine derivatives. 2H-5-Amino-6-cyano-3,7-dioxo-2-phenylmethylenethiazolo[2,3-b]pyrimidine was also subjected to ring formation affording pyrimido[4,5-d]-, pyrano[2,3-d]-, and pyrido[2,3-d]thiazolo[2,3-b]pyrimidine derivatives. 2-Anilinothiocarbonyl-3,9-dioxo-8-imino-7-phenyl-6-thioxothiazolo[2,3-b]pyrimido[4,5-d]pyrimidine and 8-amino-3,9-dioxo-6-thioxothiazolo[2,3-b]pyrimido[4,5-d]pyrimidine reacted with α-haloactive-methylene compounds to afford heterocyclic compounds containing two, fused and isolated, thiazole moieties, respectively.     

Mono- and diadducts and bicyclic adducts in reactions of 2,3-dicyano-1-ethylpyrazinium cation with C- and O-nucleophiles

Products of diaddition of O- and C-nucleophiles to the 2,3-dicyano-1-ethylpyrazinium cation were isolated for the first time. The tandem A_N—A_N reactions of 2,3-dicyano-1-ethylpyrazinium tetrafluoroborate with 1,3-diketone enolates or keto esters afforded tetrahydrofuro[2,3-b]pyrazine derivatives, whereas cyclization with ethylene glycol gave tetrahydro-1,4-dioxino[2,3-b]pyrazine. Crystallographic data on the three-dimensional structures of these compounds were reported.     

Synthesis of a New Series of Imidazo[1,5- d ]pyrido[2,3- b ][1,4]thiazines as Potential Ligands for the GABA Receptor Complex

 Starting from 2-chloro-3-nitropyridine, 1H-pyrido[2,3-b][1,4]thiazin-2(3H)-one was synthesized. This compound was reacted with potassium tert-butoxide and diethyl chlorophosphate to give the intermediate 1H-pyrido[2,3-b][1,4]thiazin-2-ylphosphate derivative, which in turn afforded the 1,2,4-oxadiazolylimidazo[1,5-d]pyrido[2,3-b]pyrazine derivatives. The title compounds are potential ligands for the γ-aminobutyric acid A/benzodiazepine receptor complex.     

Synthesis of a New Series of Imidazo[1,5-d]pyrido[2,3-b][1,4]thiazines as Potential Ligands for the GABA Receptor Complex

Summary.  Starting from 2-chloro-3-nitropyridine, 1H-pyrido[2,3-b][1,4]thiazin-2(3H)-one was synthesized. This compound was reacted with potassium tert-butoxide and diethyl chlorophosphate to give the intermediate 1H-pyrido[2,3-b][1,4]thiazin-2-ylphosphate derivative, which in turn afforded the 1,2,4-oxadiazolylimidazo[1,5-d]pyrido[2,3-b]pyrazine derivatives. The title compounds are potential ligands for the γ-aminobutyric acid A/benzodiazepine receptor complex. Corresponding author. E-mail: thomas.erker@univie.ac.at Received February 22, 2002. Accepted March 6, 2002     

Synthesis of a New Series of Imidazo-[1,5-a]pyrido[2,3-e]pyrazines as Potential Ligands for the GABA Receptor Complex

Summary.  Starting from 2-chloro-3-nitropyridine, 2-isopropyl-1,4-dihydropyrido[2,3-b]pyrazin-2(3H),3-dione was synthesized. This compound was reacted with potassium tert-butoxide and diethyl chlorophosphate to afford an intermediate dihydropyrido[2,3-b]pyrazin-2-ylphosphate derivative which in turn furnished the desired 1,2,4-oxadiazolylimidazo[1,5-a]pyrido[2,3-e]pyrazine derivatives with 5-alkyl-3-isocyanomethyl-1,2,4-oxadiazoles in the presence of additional tert-butoxide. The title compounds are potential ligands for the γ-aminobutyric acid A/benzodiazepine receptor complex. Received November 26, 2001. Accepted December 3, 2001     

Synthesis and Transformations of 3-Ethoxycarbonyl-2-(N-R-thioureido)thiophenes

3-Ethoxycarbonyl-2-(N-R-thioureido)-4,5,6,7-tetrahydrobenzo[b]thiophenes were obtained by the reaction of 2-amino-3-ethoxycarbonyl-4,5,6,7-tetrahydrobenzo[b]thiophene with isothiocyanates and of 3-ethoxycarbonyl-2-isothiocyanato-4,5,6,7-tetrahydrobenzo[b]thiophene with primary and secondary amines. The cyclization paths of the products leading to derivatives of thieno[2,3-d]pyrimidine and thieno[2,3-d]-1,3-thiazine were studied. The corresponding S-substituted derivatives were obtained by the alkylation of 3-R-2-thioxo-3,4,5,6,7,8-hexahydrobenzo[b]thieno[2,3-d]pyrimidin-4-ones.     

K-region oxides and imines of benzo[b]phenanthro[2,3-d]thiophene and benzo[b]phenanthro[3,2-d]thiophene

The syntheses of the K-oxides and K-imine derivatives of benzo[b]phenanthro[2,3-d]thiophene and benzo-[b]phenanthro[3,2-d]thiophene are described. The parent hydrocarbons 1 and 2 were oxidized with osmium tetroxide and sodium metaperiodate, and the dialdehydes 12 and 18 so formed, cyclized to the corresponding epoxides 1a,12b-dihydrobenz[b]oxireno[9,10]phenanthro[2,3-d]thiophene ( 7 ) and 1a,12b-dihydrobenz-[b]oxireno[9,10]phenanthro[3,2-d]thiophene ( 13 ). Reaction of the oxiranes with sodium azide gave mixtures of azido-alcohols that, in turn, were transformed to the thiaarene imines 1a,12b-dihydro-1H-benz[b]azirino-[9,10]phenanthro[2,3-d]thiophene ( 8 ) and 1a,12b-dihydro-1H-benz[b]azirino[9,10]phenanthro[3,2-d]thiophene ( 14 ), respectively, with the aid of tri-n-butylphosphine.     

The synthesis of benzo[b]phenanthro[d]thiophenes and anthra[b]benzo[d]thiophenes

The synthesis of benzo[b]phenanthro[2, 3-d]thiophene ( 5 ), benzo[b]phenanthro[4, 3-d]thiophene ( 6 ), benzo-[b]phenanthro[2, 1-d]thiophene ( 9 ), benzo[b]phenanthro[3, 2-d]thiophene ( 14a ), anthra[1, 2-b]benzo[d]thiophene ( 24 ), anthra[2, 3-b]benzo[d]thiophene ( 29 ) and anthra[2, 1-b]benzo[d]thiophene ( 30 ) is described as well as the preparation of 13-methylbenzo[b]phenanthro[3, 2-d]thiophene ( 14b ).     

A new condensed system,benzothienofurazanothiepine trioxide

The dimetallation of phenyl thienyl sulfones was used to obtain derivatives of benzo[b]thieno[3,2-f]fura2ano[3,4-d]thiepine-1(3),7,7-trioxide, which is anew condensed system.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 913–916, April, 1990.     

Nitrogen bridgehead compounds. Part 45 [1]. Synthesis of 6-arylhydrazono-6,7,8,9-tetrahydro-11H-pyrido-[2,1-b]quinazolin-11-ones

A series of 6-arylhydrazono-6,7,8,9-tetrahydro-11H-pyrido[2,1-b]quinazolin-11-ones 3–37 , conveneint starting materials for indolopyridoquinazolines, were prepared by diazonium coupling between aryldiazonium chlorides and 6,7,8,9-tetrahydro- 2 , 6-formyl-5,7,8,9-tetrahydro- 39 , 6-(dimethylamino)methylene-6,7,8,9- 38 or 6-carboxyl-5,7,8,9-tetrahydro-11H-pyrido[2,1-b]quinazolin-11-ones 43 . The arylhydrazono derivatives were also prepared from 6-bromo- 45 or 6,6-dibromo-6,7,8,9-tetrahydro-11H-pyrido[2,1-b]quinazolines 46 with arylhydrazines. The structures of the 6-arylhydrazonopyridoquinazolines were characterized by uv and ¹H nmr spectroscopy. The 6-arylhydrazono derivatives show a solvent-dependent E-Z isomerism.     

Halogenation of Imidazo[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridin-2-one Derivatives

Chlorination and bromination of 2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one and its N-methyl-substituted derivatives in acetic acid at 90–95°C leads to formation of the corresponding 5,6-dichloro(dibromo)-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones. Iodination of the same substrates with ICl under analogous conditions yields 6-iodo derivatives. Chlorination of 6-iodo-1,3-dimethyl-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one is accompanied by replacement of the iodine atom by chlorine with formation of 5,6-dichloro-1,3-dimethyl-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one. Bromination of 6-bromo- and 6-chloro-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones gives 5,6-dibromo- and 5-bromo-6-chloro-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones, respectively.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 4, 2005, pp. 586–589.Original Russian Text Copyright © 2005 by Yutilov, Lopatinskaya, Smolyar, Gres’ko.     

4,5-Diamino-1-phenyl-1,7-dihydro-6<Emphasis Type="Italic">H</Emphasis>-pyrazolo[3,4-<Emphasis Type="Italic">b</Emphasis>]pyridin-6-one in the synthesis of fused tricyclic systems

Starting from the substituted 4,5-diaminopyrazolo[3,4-b]pyridine, derivatives of a number of tricyclic systems, viz., imidazo[4,5-d]pyrazolo[3,4-b]pyridine, pyrazolo[3,4-b][1,2,5]thiadiazolo[3,4-d]pyridine, pyrazolo[3,4-b][1,2,3]triazolo[4,5-d]pyridine, and [1,3]oxazolo[5,4-b]pyrazolo[4,3-e]pyridine, were synthesized and reaction schemes for the processes were proposed.     

1, 3-dipolar cycloaddition of diazomethane to azolopyridazines. The synthesis of 8-methyl-8H- and 9-methyl-9H-pyrazolo[3, 4-d]-s-triazolo[4, 3-b]pyridazine and 1-methyl-1H- and 2-methyl-2H-imidazo[1, 2-b]pyrazolo[3, 4-b]pyridazine derivatives

The transformations of 7-methyl-7H- and 8-methyl-8H-pyrazolo[4, 3-d]tetrazolo[1, 5-b]pyridazines 1, 2, 9 and 10 into 8-methyl-8H- and 9-methyl-9H-pyrazolo[3, 4-H]-s-triazolo[4, 3-b]pyridazines 7 and 8 , and 1-methyl-1H-and 2-methyl-2H-imidazo[1, 2-b]pyrazolo[3, 4-d]pyridazines 13 and 14 are described.     

Synthese von 2-Methylen-2,3-dihydro- und 2-Methyl-5H-thiazolo[3,2—a]thieno[2,3—d]pyrimidinen

The title substances and their [1]benzothieno analogues were synthesized by reaction of 3-allyl-2-mercapto-([1]benzo)thieno-[2.3—d]pyrimidine-4(3H)-ones with Br₂ to 2-bromomethyl-2.3-dihydro-thiazolo[3.2—a]([1]benzo-)thieno[2.3—d]pyrimidine-5-ones, which on treatment with morpholine did not give the corresponding morpholine derivatives but elimination to the exocyclic double bond. These 2-methylene-2.3-dihydro-products were isomerized by H₂SO₄ to the corresponding 2-methyl compounds.