Convenient Synthesis of 3-(1-Carboxyalkyl)pyrido[2,3-d]pyrimidine-2,4-diones

A cheap and safe synthetic route to obtain 3-(1-carboxyalkyl)pyrido[2,3-d]pyrimidinediones (carboxyalkyl = -CHRCO₂H; R = H; CH₂; CH₂Ph; Ph; CH₂ (C₃H₃N₂); (CH₂)₂CO₂H; CH₂CO₂H) starting from 2,3-pyridinedicarboxylic acid is described. A process scheme consistent with empirical observations is proposed.     

[3,4]-annulated pyrroles 1. Polynuclear heterocyclic systems based on pyrrolo[3,4-d]pyrimidine-2,4-dione

The intramolecular electrophilic substitution in 6-functionalized 1,3-dimethyl-1H-pyrrolo[3,4-d]pyrimidine-2,4(3H,6H)-diones was used for the synthesis of pyrimido[4′,5′:3,4]-pyrrolo[1,2-a]quinoxaline-8,10(7H,9H)-dione, pyrimido[4′,5′:3,4]pyrrolo[2,1-c][1,2,4]benzo-triazine-8,10(7H,9H)-dione, and 2H-pyrimido[4′,5′:3,4]pyrrolo[1,2-a]indole-2,4,11(1H, 3H)-trione derivatives. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2180–2185, December, 2006.     

Synthesis of novel 2,3-substituted-2,4-dihydro-pyrazolo[4,3-d]pyrimidine-5,7-diones

Novel 2,3-substituted-2,4-dihydro-pyrazolo[4,3-d]pyrimidine-5,7-diones were successfully synthesized with moderate to good yields using a new synthetic approach. The structures of the regio-isomers in this series were determined by single crystal X-ray analysis and NMR spectra.     

Synthesis of pyrrolo[2,3-d]pyrimidine-2,4-diones by sunlight photolysis of N-(5-vinyluracil-6-yl)sulfilimines

Uracil derivatives having a vinyl group at the C-5 position and a sulfilimine moiety at the C-6 position were prepared and cyclized to 1,3,6-trisubstituted pyrrolo[2,3-d]pyrimidine-2,4-diones by sunlight photolysis in good yields.     

DMF acetals as alkylating and cyclizing agents: A facile route to substituted pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-diones

Summary Several 7-methyl-5-alkyl-2-vinylpyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-diones were prepared. The successful cyclization and alkylation of 6-(-methylbenzylidenehydrazino)-1-methyluracils2a–d using dimethylformamide acetals at high temperature provided6a–d,7a–d, and8a–d. Treatment of6a–d and7a–d with acid afforded 7-methyl-5-alkylpyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-diones9a,b; under the same conditions,3a–d reacted to 7-methylpyrazolo[3,4-d]-pyrimidine-4,6(5H)-dione (4) in good yield.

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DMF-Acetale als Alkylierungs- und Ringschlußreagentien: ein einfacher Weg zu substituierten Pyrazolo[3,4-d]pyrimidin-4,6(5H,7H)-dionen

Zusammenfassung Es wurden verschiedene 7-Methyl-5-alkyl-2-vinylpyrazolo[3,4-d]pyrimidin-4,6(5H,7H)-dione hergestellt. Cyclisierung und Alkylierung der 6-(-Methylbenzylidenhydrazino)-1-methyl-uracile2a–d mit Hilfe von Dimethylformamidacetalen bei hohen Temperaturen ergab6a–d,7a–d und8a–d. Behandlung von6a–d und7a–d mit Säure lieferte die 7-Methyl-5-alkylpyrazolo[3,4-d]pyrimidin-4,6(5H,7H)-dione9a,b; unter den gleichen Bedingungen reagierten3a–d in guter Ausbeute zu 7-Methylpyrazolo[3,4-d]pyrimidin-4,6(5H)-dion (4).

     

Synthesis and properties of 1,2,4-triazolo[4,3-d]-1,2,4-triazolo-[3,4-f]furazano[3,4-b]pyrazines

New methods for the synthesis of 1,2,4-triazolo[4,3-d]-1,2,4-triazolo[3,4-f]furazano[3,4-b]pyrazines with functional substituents of various types are proposed and some properties of these compounds are studied. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1776–1778, October, 1993.     

Pyrrolopyrimidines. 4. A convenient method for the production of 6-(2-aminovinyl)-5-nitropyrimidines and their transformation into pyrrolo[3,2-d]pyrimidines

A convenient method is proposed for the production of 6-(2-aminovinyl)pyrimidine-2,4-diones, involving the reaction of 6-methyluracils with triethyl orthoformiate and secondary amines.For Communication 3, see [1]Rostov State University, Rostov-on-Don, Russia; e-mail: zeb@chimfak.rsu.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 368–371, March, 2000.     

Synthesis of thieno[3,4-d]pyrimidines by the reactions of 3-amino-4-carbamoylthiophene derivatives with 1,3-dicarbonyl compounds

The reactions of ethyl 3-amino-4-carbamoyl-5-methylthiophene-2-carboxylate with 1,3-dicarbonyl compounds were studied. During the reactions, the corresponding ketone is eliminated to give ethyl 5-methyl-4-oxo-3,4-dihydrothieno[3,4-d]pyrimidine-7-carboxylates.     

Synthesis of functionalized pyrimidine-4-thiones and derivatives of pyrido[2,3-d]pirimidine-5-one from monoacylketene aminals

Monoacylketene aminals containing an unsubstituted NH₂ group react as C-nucleophiles with benzoyl isothiocyanate to give the corresponding thioamides which undergo cyclization by sodium methoxide in methanol to afford 6-R-amino-5-acetyl-2-phenyl-3H-pyrimidine-4-thiones. A scheme for constructing the pyrido[2,3-d]pyrimidine system from keteneaminals is offered. The reaction of 6-R-amino-5-acetyl-2-phenyl-3H-pyrimidine-4-thiones with dimethylformamide dimethylacetal leads to 8-R-N-4-methylthio-8H-pyrido-[2,3-d]pyrimidine-5-ones. Cyclization of 5-acetyl-6-benzoylamino-4-methylthio-2-phenylpyrimidine by sodium methoxide yields N-unsubstituted 4-methylthio-8H-pyrido-[2,3-d]pyrimidine-5-one.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1932–1937, November, 1993     

Isolation of Intermediates in the Synthesis of Thieno[2,3-d]pyrimidine-2,4(1H,3H)-diones Using Microwave Irradiation

A simple and fast method for the isolation of intermediates in the synthesis of 3-arylthieno[2,3-d]pyrimidine-2,4(1H,3H)-diones has been developed by microwave-assisted condensation of ethyl 2-amino-4,5-dimethylthiophene-3-carboxylate with aryl isocyanates. The intermediates, subsequently, underwent cyclization in t-butanol in the presence of potassium t-butoxide on heating to reflux to give the desired bicyclic products, 3-arylthieno[2,3-d]pyrimidine-2,4(1H,3H)-diones.     

A facile one-pot synthesis of new thieno- [2,3-d]pyrimidine-2,4（1H,3H）-dione derivatives

A facile one-pot synthesis of new 3-arylthieno[2,3-d]pyrimidine-2,4(1H,3H)-diones via base-catalyzed cyclocondensation of ethyl 2-amino-4,5-dimethylthiophene-3-carboxylate with aryi isocyanates is described.     

Synthesis of fluoro-containing pyrimidinones from hexafluoroacetone(ethoxycarbonylimine)

Cyclocondensation of hexafluoroacetone(ethoxycarbonylimine) with various 1,3-C,N-bisnucleophiles afforded novel bis(trifluoromethyl)pyrimidinones, including fused ones, in preparative yields. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1474–1478, June, 2005.     

Synthesis of 6-[4-(allyl/phenyl)-5-thioxo-1,2,4-triazol-3-yl]pyrimidine-2,4-diones and their reaction with electrophiles

Cyclization of 1-(2,4-dioxo-1,2,3,4-tetrahydropyrimidin-6-yl)carbonyl-4-R-thiosemicarbazides in basic medium gave 6-(4-R-5-thioxo-1,2,4-triazol-3-yl)pyrimidine-2,4-diones (R = Allyl, Ph). Alkylation of the latter with iodomethane occurred at the sulphur atom to give the corresponding methylsulfanyl derivatives. Acetylation using acetyl chloride occurred at the N₍₁₎ atom of the triazole ring to the corresponding acetyl derivative when R = Ph but for R = Allyl the acetylation did not occur under the same conditions. In the presence of bromine in refluxing methanol the indicated allyl-substituted compound cyclizes to 6-bromomethyl-3-(2,4-dioxo-1,2,3,4-tetrahydropyrimidin-6-yl)-5,6-dihydrothiazolo[2,3-c]-1,2,4-triazole. Under Mannich and bromination conditions the methylsulfanyl derivatives prepared form derivatives at the 5 position of the uracil ring: 5-methylmorpholino-(piperidino)-and 5-bromo-(4-R-5-thioxo-1,2,4-triazol-3-yl)pyrimidine-2,4-diones respectively. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 906–912, June, 2006.     

Synthesis of novel coumarinyl-pyrido[2,3-d]pyrimidine-2,4-diones using task-specific magnetic ionic liquid, [AcMIm]FeCl4 as catalyst

Abstract

An acid-functionalized magnetic ionic liquid, 1-acyl-3-methylimidazolium tetrachloroferrate, [AcMIm]-FeCl₄ has been utilized for the synthesis of a series of novel highly functionalized coumarinyl-pyrido[2,3-d]pyrimidine-2,4-dione derivatives (3a-3l) by the reactions of various 3-chloro-3-(2-oxo-2H-chromen-3-yl)acrylaldehydes (1) with functionalized aryl, 6-aminouracils. The major significant of the present procedure is the use of task-specific acidic ionic liquid which act as catalyst as well as reaction medium and thus avoiding use of organic solvent and/or protic acid catalyst. The other major advantages of the protocol are (i) shorter reaction time (1?h), (ii) easy work up procedure, (iii) excellent yields of products (91-94%), and (iv) recyclability of catalyst. The compounds (3a-3l) were identified using FT-IR, ¹H NMR, and ¹³C NMR and mass spectroscopic studies.     

Novel photo-induced oxidative cyclization of 1,3-dimethyl-5-(1-arylmethylidene)pyrimidine-2,4,6(1,3,5H)-triones: synthesis and properties of areno[5,6]pyrano[2,3-d]pyrimidine-2,4(1,3H)-dionylium ions and their photo-induced autorecycling oxidizing reaction toward some amines

Novel photo-induced oxidative cyclization was accomplished to synthesize areno[b]pyrimido[5,4-e]pyran-2,4(1,3H)-dionylium ions 13a-c⁺·ClO₄⁻. Furthermore, 13a-c⁺·BF₄⁻ and their phenyl-substituted derivatives 19a,b⁺·BF₄⁻ were alternatively synthesized by the reaction of salicylaldehyde and its naphthyl derivatives with barbituric acids and subsequent treatment with aq. HBF₄. Structural characteristics of 13a-c⁺ and 19a,b⁺ were clarified on inspection of the UV-vis and NMR spectral data as well as X-ray crystal analyses. The electrochemical properties were studied by the CV measurement. In a search for reactivity, reactions of 13a-c⁺·BF₄⁻ with some nucleophiles, hydride, benzylamine, and H₂O, were also carried out. The photo-induced autorecycling oxidation reactions of 13a-c⁺·BF₄⁻ toward some amines under aerobic conditions were carried out to give the corresponding imines (isolated by converting to the corresponding 2,4-dinitrophenylhydrazones) in 643-3600% yield (recycling number of 13a-c⁺·BF₄⁻: 6.4-36.0).     

Novel Synthesis of 1,8-Alkanopyrido[3,4-d]pyridazine: a New Ring System

Cycloalkylidenemalononitriles couple with various diazonium salts to yield the corresponding cycloalkeno[c]pyridazines, which react with trichloroacetonitrile to give the 1,8-alkanopyrido[3,4-d]pyridazines. The reaction of cycloalkenopyridazines with DMF dimethylacetal gives enamine derivatives, which can be converted to 1,8-alkanopyrido[3,4-d]pyridazines via treating with hydrazine hydrate or aromatic amines. Substituted cycloalkenopyridines react with diazoaminobenzene to afford the corresponding 1,8-alkanopyridopyridazines.     

Synthesis and halogenation of propargyl pyrazolo-[3,4-d]pyrimidine thioether

The reaction of 4-imino-1-methyl-5-phenyl-6-propargylthio-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidine with halogens leads to the formation of (Z)-8-halomethylene-4-imino-1-methyl-5-phenyl-4,5,7,8-tetrahydro-1H-pyrazolo[4,3-e][1,3]thiazolo[3,2-a]pyrimidinium trihalide. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1085–1088, July, 2008.     

Imidazo[1,5-a]- and Thiazolo[3,4-a]quinoxalines Based on 3-(a-Thiocyanobenzyl)quinoxalin-2(1H)-one

When 3-(a-thiocyanobenzyl-2(1H)-one is heated, competing processes of [a]-annelation of the imidazole or thiazole rings occurs with formation of imidazo[1,5-a]- and thiazolo[3,4-a]quinoxalin-4(5H)-ones.     

Synthesis of Derivatives of Pyrazolo[3,4-d]pyrimidines by Reaction of 3,5-Bis(dimethylaminomethylene)amino-4-methoxycarbonylpyrazole and 4-Cyanopyrazole with Amines

The reaction of 3,5-di-(N,N-dimethylaminomethylene)amino-4-methoxycarbonylpyrazole and 3,5-di-(N,N-dimethylaminomethylene)amino-4-cyanopyrazole with different amines occurs with formation of pyrazolo[3,4-d]pyrimidines. In some reactions, an excess of amines leads to their conversion to N,N-dimethylformamidine derivatives. The structure of the compounds obtained has been confirmed by ¹H NMR and ¹³C spectroscopy.     

Reaction of 6-amino-1,3-dimethyluracil with hexafluoroacetone and ethyl trifluoropyruvate benzoylimines

Heating of 6-amino-1,3-dimethyluracil with hexafluoroacetone and ethyl trifluoropyruvate benzoylimines in DMF in the presence of Et₃N results in 1,3-dimethyl-7-phenyl-5,5-bis(trifluoromethyl)-1,2,3,4,5,8-hexahydropyrimido[4,5-d]pyrimidine-2,4-dione and 5-benzoylamido-1,3-dimethyl-5-trifluoromethyl-1,2,3,4,5,6-hexahydropyrrolo[2,3-d]pyrimidine-2,4,6-trione, respectively.