Thieno[2,3-d]pyrimidines. I. A new method for the preparation of esters and amides of thieno[2,3-d] pyrimidine-6-carboxylic acids

A novel method for the preparation of esters and amides of thieno[2,3-d]pyrimidine-6-carb-oxylic acids was described. A typical example was the direct formation of ethyl 5-amino-2-methylthiothieno[2,3-d]pyrimidine-6-earboxylate(IIIa) from 4-chloro-2-methylthio-5-pyrimidine-carbonitrile (Ia) and ethyl mercaptoacetate in refluxing ethanol containing sodium carbonate. Displacement of the methylthio group in IIIa by various amines gave the corresponding amino derivatives. The reactions of IIIa and related compounds with acetylating agents such as acetic anhydride or chloroacetyl chloride gave various products. Treatment of 5-carbethoxy-4-chloro-2-phenylpyrimidine(IV) with methyl mercaptoacetate afforded the dechloro intermediate diester Va, which cyclized on reaction with sodium ethoxide to form methyl 5-hydroxy-2-phenylthieno-[2,3-d]pyrimidine-6-carboxylate (Vla). The synthesis was expanded to include the preparation of various new 2,4,5-trisubstituted thieno[2,3-d]pyrimidine-6-carboxylic acid esters and amides (Charts I-V).     

Palladium-catalyzed reaction of methyl 5-amino-4-chloro-2-methylthiopyrrolo[2,3-<Emphasis Type="Italic">d</Emphasis>]-pyrimidine-6-carboxylate with arylboronic acids. Synthesis of 1,3,4,6-tetraazadibenzo[<Emphasis Type="Italic">cd,f</Emphasis>]-azulene heterocyclic system

Densely substituted methyl 5-amino-4-aryl-7-methyl-2-methylthio-7H-pyrrolo[2,3-d]pyrimidine-6-carboxy- lates were synthesized by the palladium-catalyzed cross-coupling reaction of methyl 5-amino-4-chloro-7-methyl-2-methylthio-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylate with arylboronic acids using Pd(OAc)₂/dicyclohexyl(2-biphenyl)phosphine/K₃PO₄ as a catalyst system. Reaction of methyl 5-amino-4-chloro-7-methyl-2-methylthio-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylate with 2-formylphenyl- boronic acid led to a novel heterocyclic system – 1,3,4,6-tetraazadibenzo[cd,f]azulene.     

Synthesis of 5,8-dihydro-5-oxo-2-(3- or 4-pyridinyl)-pyrido[2,3-d]pyrimidine-6-carboxylic acids and the reinvestigation of the thermal cyclization of diethyl (2-hydroxy-4-pyrimidinyl)amino-methylenemalonate

Diethyl [2-(3- or 4-pyridinyl)-4-pyrimidinyl]aminomethylenemalonates 5 prepared by the reaction between 2-(3- or 4-pyridinyl)-4-pyrimidinamines 3 and diethyl ethoxymethylenemalonate ( 4 ) were thermally cyclized to afford ethyl 5,8-dihydro-5-oxo-2-(3- or 4-pyridinyl)pyrido[2,3-d]pyrimidine-6-carboxylates 6 . The later were alkylated with ethyl iodide and then saponified to give 5,8-dihydro-8-ethyl-5-oxo-2-(3- or 4-pyridinyl)pyrido-[2,3-d]pyrimidine-6-carboxylic acids 2 . Thermal cyclization of diethyl (2-hydroxy-4-pyrimidinyl)amino-methylenemalonate ( 8 ) gave ethyl 1,6-dihydro-4,6-dioxo-4H-pyrimido[1,6-a]pyrimidine-3-carboxylate ( 10 ) instead of ethyl 5,8-dihydro-2-hydroxy-5-oxopyrido[2,3-d]pyrimidine-6-carboxylate ( 9 ) as previously claimed.     

2-甲硫基-7(5)-取代-3-吡唑并[1,5-a]嘧啶甲酸乙酯的区域选择性合成与2D NMR 研究

利用3-甲硫基-4-乙氧羰基-5-氨基-1H-吡唑分别与甲基/芳基烯胺酮反应, 合成了8种新的化合物2-甲硫基-7-取代-3-吡唑并[1,5-a]嘧啶甲酸乙酯(3a～3g)和2-甲硫基-5-甲基-3-吡唑并[1,5-a]嘧啶甲酸乙酯(4a). 化合物的结构均经元素分析, IR, ¹H NMR, MS所证实, 异构体3a和4a的结构进一步由¹³C NMR, HMQC和HMBC确认. 同时, 探讨了区域选择性合成吡唑并[1,5-a]嘧啶类化合物可能的反应机理, 并对部分化合物杀菌活性进行了测试.     

Synthesis of Dispiro[indoline-3,3′-pyrrolo[2,1-a]isoquinoline-1′,2′′-thiazolo[3,2-a]pyrimidine] Derivatives via Cycloaddition Reactions

Russian Journal of General Chemistry - The 1,3-dipolar cycloaddition reaction of ethyl (Z)-2-(2-methoxy-2-oxoethylidene)-7-methyl-3-oxo-5-aryl-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidine-6-carboxylate...     

Synthesis of 8-amino-4-methylthio-6-methyl-2-(β-D-ribofuranosyl)-2,6-dihydro-1,2,3,5,6,7-hexaazaacenaphthylene and an unusual reductive ring-opening of the 1,2,3,5,6,7-hexaazaacenaphthylene ring system

The tricyclic nucleoside 8-amino-4-methylthio-6-methyl-2-(β-D-ribofuranosyl)-1,2,3,5,6,7-hexaazaacenaphthylene ( 3 ) was synthesized from 3-cyano-4,6-bis(methylthio)-1-(β-D-ribofuranosyl)pyrazolo[3,4-d]pyrimidine ( 1 ). Attempts to synthesize 8-amino-6-methyl-2-(β-D-ribofuranosyl)-1H-2,6-dihydro-1,2,3,5,6,7-hexaazaacenaphthylene ( 5 ) ([an aza analog of 6-amino-4-methyl-8-(β-D-ribofuranosyl)-1,3,4,5,8-pentaazaacenaphthylene (TCN)], which is a potent antitumor agent), by the treatment of 3 with Raney nickel did not afford the desired aza analog of TCN. Instead, it was established that a reductive cleavage of the pyridazine moiety of 3 had occurred to give 4-methylamino-6-methylthio-1-(β-D-ribofuranosyl)-1H-pyrazolo[3,4-d]pyrimidine-3-carboxamidine ( 6 ). Assuming that solubility was a problem in the reductive step, the isopropylidene derivative of 3 , 8-amino-6-methyl-4-methylthio-2-(2,3-O-isopropylidene-β-D-ribofuranosyl)-2,6-dihydro-1,2,3,5,6,7-hexaazaacenaphthylene ( 8 ), was treated with Raney nickel, only to observe that a similar reductive ring cleavage of 8 had occurred to afford 4-methylamino-6-methylthio-1-(2,3-O-isopropylidene-β-D-ribofuranosyl)-1H-pyrazolo[3,4-d]pyrimidine-3-carboxamidine ( 10 ) and 4-methylamino-1-(2,3-O-isopropylidene-β-D-ribofuranosyl)-1H-pyrazolo[3,4-d]pyrimidine-3-carboxamidine ( 11 ). Structural assignments for all products were established by physico-chemical procedures.     

Synthesis of New Pyrido[4″,3″:4″,5″]thieno[2″,3″:4,5]pyrimido[2,1-b][1,3,4]thiadiazine Derivatives

Ethyl 2-methyl-11-oxo-9, 10-dihydro-1 H , 11 H -pyrido[4",3":4',5']thieno[2',3':4,5]pyrimido[2,1-b][1,3,4]thiadiazine-8(7 H )-carboxylate 7 has been synthesised by the reaction of ethyl 3-amino-4-oxo-2-thioxo-1,3,4,5,6,8-hexahydropyrido[4',3':4,5]thieno[2,3-d]pyrimidine-7(2 H )-carboxylate 2 with allylbromide followed by treatment with bromine and subsequent dehydrobromination of the brominated product 5 with ethanolic sodium hydroxide. Its isomeric ethyl 2-methyl-11-oxo-9,10-dihydro-3 H ,11 H -pyrido[4",3Prime;:4',5']thieno[2',3':4,5]pyrimido[2,1-b][1,3,4]thiadiazine-8(7 H )-carboxylate 8 has been obtained by condensation of 2 with chloroacetone followed by cyclization of the intermediate 9 with p -toulenesulfonic acid. The thiadiazino derivatives 11 , 13 , 15 were prepared through the reaction of 2 with the appropriate f -halocarbonyl compounds followed by cyclization reactions of the intermediates 10 , 12 , 14 .     

One-Pot synthesis of N-heterocyclic compounds from cyclopropenethione derivatives

The one-pot reaction of 2-tert-butylthio-3-phenylcyclopropenethione (1a) and its 3-(2-thienyl) derivative (1b) with lithium pyrrolidinide at -70 degrees C, followed by methylation with methyl iodide, gives 6-methylthio-5-phenyl-2,3-dihydro-1H-pyrrolizine (2a) and its 5-(2-thienyl) derivative (2b), respectively. The reaction of 2-tert-butylthio-3-(pyrrolidin-1-yl)cyclopropenethione (1c) with phenyllithium gives also 2a in a high yield under similar conditions, and the reactions of 1a with N-lithium salts of 3-pyrroline, hexamethyleneimine, indoline, and carbazole, piperidine-potassium tert-butoxide mixture, and phenyllithium give 6-methylthio-5-phenyl-3H-pyrrolizine (3), 2-methylthio-3-phenyl-6,7, 8,9-tetrahydro-5H-pyrrolo[1,2-a]azepine (5), 6-tert-butylthio-5-methylthio-4-phenyl-1,2-dihydro-6H-pyrrolo[3,2, 1-ij]quinoline (6), 4-tert-butylthio-5-methylthio-6-phenyl-4H-pyrido[3,2,1-jk]carbazole (7), 2-methylthio-3-phenyl-5,6,7,8-tetrahydroindolizine (4), and 1-tert-butylthio-2-methylthio-3-phenylindene (9), respectively. The structures of 2a and 3 were determined by X-ray analyses of their tricarbonylchromium complexes.     

Interaction of Cyclic Schiff's Bases with 2-Methylthiopyrimidine-4,6-dione Enol Acetate. Synthesis of 5-(2-Acetyl-6,7-dimethoxy-1,2,3,4-tetrahydro-1-isoquinolyl)-6-hydroxy-2-methylthio-1,4-dihydro-4-pyrimidinones

5-(2-Acetyl-1,2,3,4-tetrahydro-1-isoquinolyl)-6-hydroxy-2-methylthio-1,4-dihydro-4-pyrimidinones have been obtained by the interaction of 3,4-dihydroisoquinolines with 2-methylthio-4-oxo-1,4-dihydro-6-pyrimidinyl acetate. It was shown that N,O-methyl derivatives are formed in interaction of the obtained products with diazomethane.     

On triazoles. XXII. Synthesis of Dialkyl (3-Q-1,2,4-triazol-5-yl)iminodithiocarbonates

Isomeric dialkyl and diaralkyl[1-, 2- and 4-(alkyl, aralkyl and aryl)-3-Q-1,2,4-triazole-5-yl]iminodithiocarbonates 4a-c (R ≠ H) were synthesised and their spectral data compared. The uv, cmr and ms rules elaborated helped to prove the tautomeric structure of the non-substituted derivatives 4 (R ? H). In case of dimethyl (3-methylthio-1,2,4-triazole-5-yl)iminodithiocarbonate this is the first time ever crystalline triazole desmotropes 4a/17 and 4b/17 could be isolated. The sodium salts of 4 (R ? H) could be further alkylated and aralkylated to yield the corresponding 4 (R ? alkyl and aralkyl) type derivatives. Providing the above reaction in the presence of carbon disulfide the dithiocarbomethoxy derivative 7 was obtained.     

1，2－二氢－3H－吲哚－3－酮类化合物的光化学合成

１，２－二氢－３Ｈ－吲哚－３－酮类化合物的光化学合成凌可庆（淮北煤炭师范学院化学系，淮北，２３５０００）关键词吲哚衍生物，单重态氧反应，１，２－二氢－３Ｈ－吲哚－３－酮衍生物，光合成１，２－二氢－３Ｈ－吲哚－３－酮是重要的有机合成中间体，广泛用于多种...     

Electrochemical oxidation of 4,5,6,7-tetrahydro-1H-pyrazolo[3,4-d] pyrimidine-4,6-dione (oxipurinol) at the pyrolytic graphite electrode

The electrochemical oxidation of 4,5,6,7-tetrahydro-1H-pyrazolo[3,4-d] pyrimidine-4,6-dione (oxipurinol) at the pyrolytic graphite electrode (PGE) has been studied. Oxipurinol exhibits up to three voltammetric oxidation peaks at the PGE between pH 1–12. The first pH-dependent peak (peak I_a) is proposed to be an initial, irreversible 2e-2H⁺ reaction to give 5,6-dihydro-4H-pyrazolo[3,4-d] pyrimidine-4,6-dione. This primary product further reacts by two routes. The major route, accounting for ca. 90% of the latter compound, involves a Michael addition of water followed by further electrochemical oxidation and hydrolysis to give 5,6-dihydro-5,6-dihydroxy-5-carboxy-6-diazenouracil. The minor route involves further electrochemical oxidation of 5,6-dihydro-4H-pyrazolo[3,4-d]-pyrimidine-4,6-dione in a 2e-2H⁺ reaction to give 4,5,6,7-tetrahydro-3H-pyrazolo[3,4-d]-pyrimidine-3,4,6-trione.Decomposition and, generally, additional electrochemical reactions of 5,6-dihydro-5,6-dihydroxy-5-carboxy-6-diazenouracil result in the formation of alloxan, parabanic acid, 6-diazo-isobarbituric acid and 5′-hydroxy-5-carboxy-6,6′-azouracil. The two latter compounds have never previously been reported. Decomposition of 4,5,6,7-tetrahydro-3H-pyrazolo[3,4-d]pyrimidine-3,4,6-trione results in formation of uracil-5-carboxylic acid.Detailed reaction schemes have been proposed to explain the observed electrochemistry and the formation of the observed products.     

Five-membered 2,3-dioxo heterocycles: LXXX. Recyclization of 1H-pyrrole-2,3-diones into pyrazolo[1,5-a]pyrimidines by the action of pyrazolamine. Crystalline and molecular structure of substituted pyrazolo[1,5-a]pyrimidine

Methyl 1-aryl-3-aroyl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates reacted with 3-methyl-4-phenyl-1H-pyrazol-5-amine to give methyl 7-arylcarbamoyl-6-aroyl-2-methyl-3-phenylpyrazolo[1,5-a]-pyrimidine-5-carboxylates. The molecular and crystalline structures of methyl 6-benzoyl-7-(4-chlorophenylcarbamoyl)-2-methyl-3-phenylpyrazolo[1,5-a]pyrimidine-5-carboxylate were studied by X-ray analysis.     

Unusual reaction of 5-benzoyl-3-ethoxycarbonyl-6-methylthio-1-r-1,2-dihydropyridin-2-ones with nitrogen-containing 1,4-dinucleophiles

The reaction of 5-benzoyl-3-ethoxycarbonyl-6-methylthio-1-R-1,2-dihydropyridin-2-ones with the nitrogen-containing 1,4-dinucleophiles o-phenylenediamine, o-aminothiophenol, and ethylenediamine, proceeds as a recyclization, the products of which are derivatives of 5-(1H-benzimidazol-2-yl)-2H-2-pyranone, 5-(benzothiazol-2-yl)-2H-2-pyranone, and 5-(4,5-dihydro-1H-imidazol-2-yl)-2H-2-pyra-none respectively. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1089–1095, July, 2008.     

Acid-catalyzed cyclization of N-3-hydroxyalkyldithiocarbamates

A study was carried out on the reaction of N-3-hydroxyalkyldithiocarbamates with concentrated sulfuric acid, which may lead to the formation of alkyl derivatives of 2-methylthio-5,6-dihydro-4H-1,3-thiazines or 2-methylthio-2-thiazolines, depending on the structure of the hydroxyalkyl fragment.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 30, No. 3, pp. 415–416, March, 1994.     

Synthesis of novel dihydrothiazolo[3,2-a]pyrimidinone derivatives

Condensation of 2-amino-4-hydroxy-2-mercaptopyrimidine (2) hydrate and ethyl 4-bromocrotonate gave a mixture of ethyl 7-amino-2,3-dihydro-5-oxo-5H-thiazolo[3,2-a]pyrimidine-3-acetate (4) and 2a,3-dihydro-1-thia-5,8,8b-triazaacenaphthylene-4,7(2H)-dione (5) whereas reaction of 2 with 4-bromocrotononitrile afforded only 7-amino-2,3-dihydro-5-oxo-5H-thiazolo[3,2-a] pyrimidine-3-acetonitrile. Reaction of the tricycle 5 (which was isolated as a hemihydrate) with excess methyl iodide/potassium carbonate in dimethylformamide resulted in both ring hydrolysis and methylation to give 3,4-dihydro-1,7-dimethyl-4- [(methylthio)methyl]-2H-pyrimido[1,6-a]pyrimidine-2,6,8(1H,7H)-trione (10). Methylating 5 with excess methyl iodide/sodium methoxide in methanol also resulted in ring fragmentation and methylation but instead afforded methyl 7-methyl-amino-2,3-dihydro-5-oxo-7H-thiazolo[3,2-a]pyrimidine-3-acetate. The mechanistic aspects of these reactions are discussed.     

Five-membered 2,3-Dioxoheterocycles: LIX. Reaction of 3-Aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones with Acyclic β-Enaminoesters. Crystal and Molecular Structure of Ethyl 3-Benzoyl-4-hydroxy-1-o-hydroxyphenyl-5-oxo-2,3-dihydro-1H-pyrrolo-2-spiro-3′-(5-methyl-2-oxo-2,3-dihydro-1H-pyrrolo-4-carboxylate)

3-Aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones react with substituted alkyl 3-amino-2-propenoates to form substituted alkyl 3-aroyl-4-hydroxy-1-o-hydroxyphenyl-5-oxo-2,5-dihydro-1H-pyrrole-2-spiro-3′-(2-oxo-2,3-dihydro-1H-pyrrole-4-carboxylates). Crystal and molecular structure of ethyl 3-benzoyl-4-hydroxy-1-o-hydroxyphenyl-5-oxo-2,5-dihydro-1H-pyrrole-2-spiro-3′-(5-methyl-2-oxo-2,3-dihydro-1H-pyrrole-4-carboxylate) was investigated.     

Synthesis of alkyl 2-phenylnicotinates

Various alkyl 6-ethoxy-2-phenyl-5,6-dihydro-4H-pyran-3-carboxylate 2A are easily converted to the corresponding nicotinates 3 by reaction with hydroxylamine hydrochloride in refluxing absolute ethanol.     

Ring transformation of 6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine. IV (1). Reduction and reaction of 5a-acetyl-6a-ethoxycarbonyl-5a,6a-dihydro-6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine-3-carbonitriles with primary amines

The reaction of 5a-acetyl-6-ethoxycarbonyl-5a,6a-dihydro-6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine-3-carbonitrile ( 1a ) with benzylamine gave ethyl l-benzyl-5-cyano-8a,9-dihydro-2-methyl-1H-pyrrolo[3,4-e]-pyrazolo[1,5-a]pyrimidine-8a-carboxylate ( 2a ), in addition to 5-acetyl-3-benzylamino-1-(4-cyanopyrazol-3-yl)- 2-pyridone ( 3 ). Reaction of 1a with aniline gave ethyl 6-acetyl-8-anilino-3-cyano-7,8-dihydro-4H-pyrazolo-[1,5-a][1,3]diazepine-8-carboxylate ( 4 ), in addition to ethyl 3-cyano-7-methyl-6-pyrazolo[1,5-a]pyrimidine-acrylate ( 5 ). On the other hand, the same reactions of 1b with benzylamine or aniline gave 2b or 8b , respectively. Though catalytic hydrogenation of 1a over 5% palladium-carbon proceeded by ring fission of cyclopropane ring to give 9 , 1a (or 1b ) afforded 4,5-dihydro derivatives ( 13 or 15 ) by catalytic hydrogenation over platinum oxide. The reactivity of 5-methoxy-4,5,5a,6a-tetrahydro-6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine ( 16 ), which are related analogs of 1a,b , is also described.     

Synthesis of nitrogen-containing heterocycles. 8. Preparation and ring-opening of spiro[cycloalkane-[1′,2′,4′]triazolo[1′,5′-c]pyrimidine] derivatives

Diaminomethylene- and aminomethylthiomethylenehydrazones [2] of cyclic ketones 1–8 readily reacted with ethoxymethylenemalononitrile to give spiro[cycloalkane-1,2′-[1,2′,4′]triazolo[1,5′-c]pyrimidine-8′-carbonitrile] derivatives 12–19 through the electrocyclic reaction of the initially formed condensation products 26 in moderate to high yields. The spiro[cyclopentanetriazolopyrimidine] derivatives underwent ring-opening at the cycloalkane moiety upon heating in solution to give 2-alkyl-5-substituted-[1,2,4]triazolo[1,5-c]pyrimidine-8′-carbonitriles 20–23 . When an alkyl substituent was introduced into the cyclopentane ring, cleavage of the spiro compounds occurred preferentially at the cyclopentane moiety between the spiro carbon and the more branched one. In contrast, the cyclohexane ring, especially of spiro-5-amino-triazolopyrimidines 17 and 18 strongly resisted to ring-opening under similar conditions, but those of 5-methylthiotriazolopyrimidines 14 gave up to 17 percent of cleavage after prolonged heating in hot ethanol. 2-t-Butyl-5-methylthio-2,3-dihydro[1,2,4]triazolo[1,5-c]pyrimidine-8-carbonitrile 25 [R³ = C(CH₃)₃] was highly susceptible to the cleavage even at room temperature and produced the corresponding 2-unsubstituted triazolopyrimidine 24 with loss of the t-butyl group.