Analogs of pyrimidine nucleosides. 16. Racemic 2′,3′-dideoxynucleosides and their derivatives

The chlorination of 2-halomethyltetrahydrofurans and acyl derivatives of tetrahydrofuryl alcohol wasstudied; mixtures of 2,5- and 2,2-disubstituted tetrahydrofurans are formed as a result of the reaction. 2,4-Bis(trimethylsilyl) derivatives of uracil, 5-substituted uracils, and cytosine are alkylated by the resulting mixtures of -chloro ethers without separation, and mixtures of cis and transisomers of 1-(5-substituted-2-tetrahydrofuryl) and 1-(2-substituted-2-tetrahydrofuryl) derivatives of uracil, 5-substituted uracils, and cytosine are obtained. The reaction products were identified onthe basis of their PMR spectra.See [1] for Communication 15.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 101–110, January, 1982.     

A Convenient Route for the Synthesis of 4-Aryl- and 4-Aminopyrimidines

Summary. A series of ureidopropenenitriles were synthesised by Knoevenagel condensation of ArCOCH₂CN and HC(OEt)₃ in presence of ureas in a one pot reaction. These ureidopropenenitriles were cyclised to 4-aryl-5-cyano-3-substituted pyrimidines (in acid) or to 4-amino-5-benzoylpyrimidines (in base) in 60–70% yields. The amine pyrimidine derivatives were further converted to substituted uracils by hydrolysis with isopentyl nitrite in DMF. Alkylation of uracils furnished 1,3-dimethyluracil derivatives with DMS in alkali. All new compounds were characterised by spectral and analytical methods.     

A Convenient Route for the Synthesis of 4-Aryl- and 4-Aminopyrimidines

A series of ureidopropenenitriles were synthesised by Knoevenagel condensation of ArCOCH₂CN and HC(OEt)₃ in presence of ureas in a one pot reaction. These ureidopropenenitriles were cyclised to 4-aryl-5-cyano-3-substituted pyrimidines (in acid) or to 4-amino-5-benzoylpyrimidines (in base) in 60–70% yields. The amine pyrimidine derivatives were further converted to substituted uracils by hydrolysis with isopentyl nitrite in DMF. Alkylation of uracils furnished 1,3-dimethyluracil derivatives with DMS in alkali. All new compounds were characterised by spectral and analytical methods.     

Analogs of pyrimidine nucleosides

The reaction of alkoxy bromides with N₁-(-tetrahydrofuryl) derivatives of pyrimidine bases has given a series of 6-alkoxy-5-bromo-1-(-tetrahydrofuryl)-5, 6-dihydrouracils. The hydrogenation of the 1-(-tetrahydrofuryl) derivatives of uracil and of 5-fluorouracil has been studied. It has been shown that in both cases 1-(-tetrahydrofuryl)-5, 6-dihydrouracil is formed.     

N1-(2-furoylmethyl) and N1-(5-nitro-2- furoylmethyl) derivatives of uracil and its 5-substituted derivatives

The corresponding N₁-(2-furoylmethyl) and N₁-(5-nitro-2-furoylmethyl) derivatives of uracil and its 5-substituted derivatives were obtained by the reaction of 2-bromo- and 5-nitro-2-bromoacetylfurans with uracil, 5-fluorouracil, and thymine. The structures of these compounds as N₁-substituted uracils were proved by a study of the UV spectra at various pH values. The computational method of expanding the UV spectra into individual bands was used.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1268–1270, September, 1971.     

Acyclic analogs of nucleosides. Synthesis of 1,5-dihydroxy-3-oxa-2-pentyl derivatives of nucleic bases

A convenient method for the synthesis of 1,5-dihydroxy-3-oxa-2-pentyl derivatives of nucleic bases, which consists in the condensation of trimethylsilyl derivatives of nucleic bases with 1,2,5-triacetoxy-3-oxapentane in the presence of SnCl₄, is proposed. Optically active derivatives — (R)- and (S)-1-(1,5-dihydroxy-3-oxa-2-pentyl)uracil, respectively — were obtained by periodate oxidation of -L- and -D-arabinopyranosyluracil.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 223–228, February, 1988.     

Protolytic equilibrium of certain annelated azoloazines

The first and second protonations of annelated azoloazines have been investigated quantitatively in aqueous solution. Compounds investigated were pyrazolo[1,5-a]pyrimidine (pK_BH ^– 0.03±0.02, pK_BH ²⁺ –7.87±0.30), 1,2,4-triazolo[4,3-b]-1,2,4-triazine (pK_BH ⁺ –0.04±0.02, pK_BH ²⁺ –8.00±0.10), 1,2,4-triazolo[1,5-a]pyrimidine (pK_BH ⁺ 0.21±0.03, pK_BH ²⁺ –9.00±0.09) and its 6R derivatives (R=NO₂, Br, Cl). The annelated azoloazines studied are weaker bases than their unannelated analogs. According to quantum chemical calculations (AM1), protonation of these heterocycles may occur both at the azole and the azine fragments of the molecule.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 816–824, June, 2000.     

Catalytic synthesis of diazines from 1,3-diaminopropane and 3-amino-1-propanol

The transformations of 1,3-diaminopropane and 3-amino-1-propanol under pulse conditions over tungsten trioxide in an inert atmosphere at 300–500 °C were investigated. The transformation of 1,3-diaminopropane leads to the formation of saturated pyrimidine bases; the maximum selectivity of the formation of hexahydropyrimidine bases at 300 °C is 60%, while the selectivity of the formation of tetrahydropyrimidine bases is 20% (400 °C). In the case of 3-amino-1-propanol the overall yield of heterocyclic bases was less than 5%, and piperazine and pyrazine derivatives were observed as the cyclic products; the formation of pyrimidine bases was not observed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 967–973, July, 1982.     

Synthesis of 2,4-diamino-5-acetyl(ethoxycarbonyl)pyrimidines from β-dicarbonyl compounds and dicyandiamide and their use for building a pyrimido[4,5-d]pyrimidine system

2,4-Diamino-5-acetyl(ethoxycarbonyl)-6-methyl(phenyl)pyrimidines were obtained by the reaction of acetylacetone and -ketocarboxylic acid esters with dicyandiamide in the presence of Ni(OAc)₂. It was shown that annelation of the pyrimidine ring with this compound provides a convenient method for building the pyrimido[4,5-d]-pyrimidine system. New derivatives of 2-aminopyrimido[4,5-d]pyrimidine, 7-amino-3H-pyrimido[4,5-d]-pyrimidin-4-one, and 7-amino-1H,3H-pyrimido[4,5-d]-pyrimidine-2,4-dione were synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 159–164, January, 1991.     

Palladium(II) Schiff base complexes derived from sulfanilamides and aminobenzothiazoles

Schiff bases (HL) derived from sulfanilamides or aminobenzothiazoles add to Pd(OAc)₂ to give complexes of the type PdL₂ (1–7) in moderate to excellent yields. Reactions of Schiff bases containing pyrimidine groups, however, gave several products arising from competing coordination of the pyrimidine nitrogen. Palladium complexes and Schiff bases have been investigated as antifungal agents against Aspergillus niger and Aspergillus flavus.     

A study of the reaction mechanism of the catalytic intramolecular conversion of heterocycles

In order to study the reaction mechanism of the catalytic intramolecular conversion of heterocycles [1–3] and to broaden the field of their application, we have studied the dehydration over Al₂O₃ of 1-amino-3-(-tetrahydrofuryl) propane (I), 1-methylamino-1-(-tetrahydrofuryl) propane (II), and 2-(3-hydroxy-1-propyl)-1-methylpyrrolidine (III), leading in all three cases to pyrrolizidine (IV).     

Synthesis of 1-(3-halotetrahydro-2-furyl) derivatives of uracil, 5-substituted uracils,and cytosine

The cis and trans isomers of 1-(3-halotetrahydro-2-furyl) derivatives of uracil, 5-substituted uracils, and cytosine were obtained by alkylation of 2,4-bis(trimethylsilyl) derivatives of uracil, 5-substituted uracils, and cytosine with 2,3-dihalotetrahydrofurans. 2,3-Anhydro compounds are also formed in the alkylation of 5-halouracil derivatives. The physicochemical properties of the compounds obtained and the antineoplastic activities of the 5-fluorouracil derivatives were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 94–99, January, 1987.     

Protropic tautomerism and conformational isomerism of 4-(N-arylamino)-2-(1H-pyrazol-1-YL)pyrimidines

New 4-(N-arylamino)-2-(1H-pyrazol-1-yl)pyrimidine derivatives were synthesized, and the UV, IR, and PMR spectra of solutions of them in CHCl₃, CCl₄ and d₆-DMSO were studied. The questions of intermolecular association and conformational isomerism are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1114–1119, August, 1980.     

New functionalization at the 5-position of uracils by selenenylation

Electrophilic substitution of phenylselenenyl chloride at the 5-position of uracils in the presence of silver reagents, such as Ag₂O, AgBF₄, or CF₃CO₂Ag, afforded the corresponding 5-phenylselenenyluracils in excellent yields. 1,3-Dimethyl-5-phenylselenenyluracil (2a) , 5-phenylselenenyl-(2′,3′,5′-tri-O-acetyl)uridine (2b) , 5-phenylselenoxyl-1,3-dimethyluracil (3a) and 5-phenylselenoxyl-(2′,3′,5′-tri-O-acetyl)uridine (3b) were used for various transformations at C-5 or C-6 of pyrimidine bases via nucleophilic substitution, a free radical process, and a Michael-type addition utilizing the unique properties of organo-seleno groups located on C-5 of pyrimidine bases.     

Analogs of pyrimidine nucleosides. 17. Synthesis of 1-[5(2)-fluoromethyltetrahydro-2-furyl]uracils

The synthesis of 2-fluoromethyltetrahydrofuran is described, and it is shown that chlorination of the latter gives 2-chloro-5- and 2-chloro-2-fluoromethyltetrahydrofurans in a ratio of 5:1. 2,4-Bis(trimethylsilyl) derivatives of uracil were alkylated by means of the mixture of -chloro ethers without separation, and a mixture of the cis and trans isomers of 1-(5-fluoromethyltetrahydro-2-furyl)uracils and 1-(2-fluoromethyltetrahydro-2-furyl)uracils were obtained. The reaction products were identified on the basis of the PMR spectra.See [1] for communication 16.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 256–259, February, 1982.     

Synthesis and Antiviral Activity of 1-{[2-(Phenoxy)ethoxy]methyl}uracil Derivatives

The synthesis of novel 1-{[2-(phenoxy)ethoxy]methyl}uracil derivatives with different substituents in positions and 6 of the pyrimidine ring has been carried out. It has been shown that the alkylation of trimethylsilyl derivatives of uracil with 2-(4-chlorophenoxy)- and 2-(4-methylphenoxy)ethoxymethyl chloride under Hilbert-Johnson reaction conditions gives N₍₁₎-substitution products. It was found that the 1-{ [2-(phenoxy)ethoxy]methyl}uracil derivatives show viral inhibition properties relative to human immunodeficiency type 1 virus in vitro. The most active compounds are 5-bromo-6-methyluracil derivatives which suppress viral reproduction by 50% at 7.2 and 7.8 micromolar concentrations.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 726–731, May, 2005.     

Phosphorescence of nucleic acids and DNA components at 77 K

The emission spectra of nucleic acids, pyrimidine and purine nucleotides, nucleosides and bases and a series of pyrimidine derivatives were obtained using UV light excitation in glasses (ethanol and 2:1 mixtures of ethylene glycol and water (EG-H2O); also partly in butyronitrile and 2-methyltetrahydrofuran) at 77 K. The quantum yields of fluorescence phi f and phosphorescence phi p of some 30 compounds are presented; for several substituted uracils they are reported for the first time. The values cover a range from phi f = 0.0002 and phi p = 0.001 for uracil in ethanol to phi f = 0.50 for guanosine in acidic ethanol and phi p = 0.095 for guanosine-5'-monophosphate in EG-H2O (pH 6-7). The phosphorescence lifetime tau p at 77 K ranges from about 0.3 s (uracil moiety) to 3 s (adenine moiety). The measured tau p, phi f and phi p values are compared with those available in the literature.     

Synthesis of 3-O-aryl esters of (R,S)-9-(2,3-dihydoxypropyl)adenine and its pyrimidine analogs as new potential inhibitors ofS-adenosyl-L-homocysteine hydrolase

With the aim of searching for new antiviral agents of the acyclonucleoside type, 3-O-arly esters of (R,S)-9-(2,3-dihydroxypropyl)adenine adenine and its pyrimidine analogs have been synthesized. Alkylation of adenine and cytosine by aryl glycidyl ethers in the presence of potassium carbonate affords 46–76% yields of the corresponding N⁹- and N¹-substituted derivatives. The interaction of aryl glycidyl ethers with trimethylsilyl derivatives of uracil and thymine also results in 41–57% yields of N¹-monosubstituted products with identical acyclic chain structure.Scientific-Research Institute of Pharmacology at the Volgograd Medical Academy, Volgograd 400066, Russia.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 82–86, January, 1999.