Synthesis of 5-amino-6-(nitro-NNO-azoxy)-1,2,3,4-tetrazine 1,3-dioxide

Russian Chemical Bulletin - A reaction of 5-amino-6-(tert-butyl-NNO-azoxy)-1,2,3,4-tetrazine 1,3-dioxide with nitronium tetrafluoroborate affords 5-amino-6-(nitro-NNO-azoxy)-1,2,3,4-tetrazine...     

Studies on naphthyridines. Part 2 . Synthesis of 4-substituted and 6-substituted 1,6-naphthyridin-5(6H)-ones

Ethyl 4-substituted 2-methyl-5-oxo-5,6-dihydro-1,6-naphthyridine-3-carboxylates 3a-h were synthetized in a one-step reaction from diethyl 2,6-diraethylpyridine-3,5-dicarboxylates 1a-h by aminomethinylation with 1,3,5-triazine (2). The 6-substitued derivatives 6a-z,aa-ff could be obtained from diethyl 2-[2-(dimethylamino)-vinyl]-6-methylpyridine-3,5-dicarboxylate ( 4 ) either directly or via the isolated intermediate 2-[2-(arylamino)-vinyl]pyridine compounds 5a-i.     

Amidine tautomerism in the 1,3-diacyl-2-(5-substituted furfuryl)thiourea series. Molecular structure of 1,3-diacetyl-2-(5-ethoxycarbonylfurfuryl)thiourea

The effect of substituents in the furan ring on the dynamics of amidine tautomerism in 1,3-diacetyl-2-(5-R-furfuryl)thioureas is demonstrated. The conformation of 1,3-diacetyl-2-(5-ethoxycarbonylfurfuryl)thiourea was established by x-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 741–745, June, 1991.     

Synthesis of new 2-substituted 6,7-dimethoxy-1-(methylcarbamoyl)-4-spirocyclopentane-1,2,3,4-tetrahydroisoquinolines

New 2-(heterylmethyl) derivatives were synthesized from 6,7-dimethoxy-4-spirocyclopentane-1,2,3,4-tetrahydroisoquinoline-1-carboxylic acid N-methylamide and heterylmethyl chlorides. The reactions of 2-chloroacetyl-substituted tetrahydroisoquinoline with versatile secondary amines and heterylthiols afforded the corresponding 2-aminoacetyl and 2-(heterylsulfanylacetyl) derivatives of tetrahydroisoquinoline series.     

Synthesis of 5-substituted 6-methoxy-1,2,3,4-tetrahydro-β-carbolin-1-ones

The nitration and bromination of 6-methoxy-1,2,3,4-tetrahydro--carbolin-1-one were studied. 5-Nitro and 5-bromo derivatives were obtained. 5-Acetyl-1,2,3,4-tetrahydrocarbolin-1-one oxime was obtained, and its Beckmann rearrangement was studied. The use of lithium aluminum hydride leads to reduction of the 5-acetyl group to give an alcohol group, whereas reduction of the acetyl group to an ethyl group occurs in the case of reduction with a palladium catalyst. Saponification of 5-substituted carbolin-1-ones with alcoholic alkali makes it possible to obtain 4-substituted tryptamines with a carbonyl group in the 2 position. The structures of the compounds were established by means of the PMR and mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 80–85, January, 1979.     

Selective N(2) alkylation of tetrazole and 5-substituted tetrazoles by alcohols

Alkylation of tetrazole and its 5-substituted derivatives by 5-tert-butyl, isopropyl, and cyclohexyl alcohols in concentrated H₂SO₄ results in high yields of the corresponding 2-alkyltetrazoles alone, irrespective of electronic properties and size of the substituent at the 5-position of the tetrazole ring. The tert-butylation of tetrazole in phosphoric acid results in the formation of a mixture of isomeric 1- and 2-substituted derivatives, the concentration of the 1-isomer increasing with decrease in the concentration of the acid in the mixture.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1643–1647, December, 1990.     

Tetrazoles: LI. Synthesis of 5-substituted tetrazoles under microwave activation

Reaction of nitriles with sodium azide in the presence of ZnCl₂ under microwave activation (MWA) leads to the formation of 5-tetrazoles in high yields; therewith the process is 2–3 times shorter than the inactivated reaction.     

Synthesis and tautomerism of ethyl 2-(2-benzothiazolyl)-2-(6-purinyl)acetate and related compounds

Reaction of 6-chloro-9H-(2-tetrahydropyranyl)purine ( 2d ) with the sodium salt of ethyl benzothiazole-2-ace-tate ( 1 ) in dimethylformamide effects condensation of the two compounds (with loss of sodium chloride) to give the corresponding ethyl diarylacetate 4 (35%), present largely as an enol chelate tautomer. Isolated as a by-product is 6-(2-aminophenyl-1-thio)-9H-(2-tetrahydropyranyl)-purine (4%), formed via opening of the thiazole ring. Removal of the tetrahydropyranyl protective group from 4 occurs by treatment with p-toluenesulfonic acid in aqueous ethanol to produce ethyl benzothiazole-2-(6-purinyl)acetate (80%), existent largely as two enol chelate isomers. Spectral data for the various products are presented. An attempt to use 6-chloro-9-acetyl-9H-purine in place of 2d in the first reaction gives acetylation of 1 instead of condensation.     

Tetrazoles: LV. Perparation of 2-anilino-5-aryl(hetaryl)-1,3,4-oxadiazoles from 5-substituted tetrazoles under microwave activation

In reaction of 5-aryl(hetaryl)tetrazoles with phenyl isocyanate under the conditions of microwave activation the corresponding 2-anilino-5-aryl(hetaryl)-1,3,4-oxadiazoles formed in high yields. The application of the microwave activation fourfold reduced the reaction time.     

Synthesis of optically active 6-substituted 2-(aminomethyl)chromans

Three novel, optically active, 6-substituted 2-(aminomethyl)chromans were synthesized from readily available chroman 2-carboxylic acid precursors. These chroman-containing primary amines are useful building blocks for the synthesis of chroman-derived pharmaceutical agents.     

Synthesis and Acidity of 5-Phenyltetrazol-2-ylalkanoic Acids and the Corresponding 5-(5-Phenyltetrazol-2-ylalkyl)tetrazoles

We have obtained 5-phenyltetrazol-2-ylalkanoic acids and their derivatives containing terminal nitrile, amide, and tetrazol-5-yl groups. Tetrazolylalkanoic acids with two (pK _a 4.93) and three (pK _a 5.45) bridging methylene groups are weaker acids than the corresponding ditetrazoles pK _a 4.68 and 5.29 respectively). However, the acidity of 5-phenyltetrazol-2-ylacetic acid (pK _a 3.12), is higher than acidity of the corresponding ditetrazole (pK _a 3.27).     

Synthesis of various 5-(3-substituted phenyl)-2′-deoxyuridines

A series pf 5-aryl-2′-deoxyuridines has been prepared and evaluated as antiviral agents. The following substituents have been used in position 3 of the phenyl ring: chloro, iodo, amino, azido, methylthio, and vinyl. None of the new compounds showed any significant activity when tested against human immunodeficiency virus 1 (HI V-I), herpes simplex virus 1 (HSV-I), or human cytomegalovirus (HCMV).     

Synthesis and structure of 6-substituted 9-(2-ethoxy-1,3-dioxan-5-yl)purines

The reaction of 4-chloro-5-amino-6-(1,3-dihydroxy-2-propyl)aminopyrimidine with excess ethyl orthoformate gave a cyclic acetal, viz., 6-chloro-9-(2-ethoxy-1,3-dioxan-5-yl)purine, amination of which yielded 6-amino-9-(2-ethoxy-1,3-dioxan-5-yl)purine. The presence of two configurational isomers with a diaxial orientation of the purine ring and the ethoxy group in the trans isomer and an equatorial orientation of the ethoxy group in the cis isomer was established for these compounds by ¹H and ¹³C NMR and IR spectroscopy. The three-dimensional structure of trans-6-chloro-9-(2-ethoxy-1,3-dioxan-5-yl)purine was determined by an x-ray difraction study, and the trans-diaxial orientation of the purine ring and the ethoxy group was confirmed; it is shown that the dioxane ring is in an anti conformation relative to the purine ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 976–983, July, 1979.     

Synthesis of 1-(dihydroxypropyl)-5-substituted uracils

Novel 1-(dihydroxypropyl)-5-substituted uracils were synthesized in the reaction of 1-(4-nitrophenyl)-5-substituted uracil derivatives with appropriate aminopropanediols under mild conditions. In the case of 3-amino-1,2-propanediol both racemic and enantiomerically enriched products were obtained. These compounds may be considered as new building blocks for oligonucleotide synthesis.     

Synthesis and optical properties of 5-substituted 2-(2-tosylaminophenyl)benzoxazoles

Various 5-substituted 2-(2-tosylaminophenyl)benzoxazoles were synthesized. The presence of intramolecular hydrogen bonding, the strength of which depends on the nature of the substituent, was shown by means of the IR spectra of the investigated series of compounds. A correlation between v _NH and the Taft substituent constants was found. The investigated benzoxazoles have fluorescence in the yellow-green region of the spectrum; an anomalously large Stokes shift is characteristic for them. The position of the fluorescence spectrum depends on the strength of the hydrogen bond: when it becomes weaker, the spectrum is shifted bathochromically.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 472–478, April, 1973.     

Synthesis of Some Novel 5-(Arylidene)-2-imino-3(pyridin-2-yl)thiazolidin-4-one Derivatives

Treatment of 2-aminopyridine ( 1 ) with chloroacetyl chloride in dry benzene gave 2-chloro-N-(pyridin-2-yl)acetamide ( 3 ), which on further reaction with potassium thiocyanate gave 2-imino-3-(pyridin-2-yl)thiazolidin-4-one ( 4 ) as an intermediate compound for the synthesis of pyridin-2-yl substituted 2-imino-thiazolidine-4-one derivatives. Cyclocondensation reaction of ( 4 ) with a series of aromatic aldehydes gave 5-arylidene derivatives of pyridin-2-yl substituted 2-imino-thiazolidine-4-ones 5a–j . ¹ H and ¹³C NMR spectroscopy, as well as elemental analyses, were used for the identification of these new compounds.     

Study of the reaction between 2-imino-5-(chloromethyl) oxazolidine-1, 3 and metallic sodium or disodium acetylide

The reaction of 2-imino-5-(chloromethyl) oxazolidine-1, 3 with metallic sodium or disodium acetylide is investigated. Conditions are found for obtaining 1, 2-bis(2-iminooxazolil-5-yl)-ethane and 1, 4-bis(2-iminooxazolid-5-yl) but-2-yne, respectively saponified to 1, 6-diaminohexane-2, 5-diol and 1, 8-diaminooct-4-yne-2, 7-diol. It is intended to use these compounds as monomers for preparing polyamide resins.     

Synthesis of 6-substituted 9-(dihydroxyalkyl) purines

5-Amino-6-chloro-4-dihydroxyalkylaminopyrimidines, which are cyclized to 6-chloro-9-(dihydroxyalkyl)purines, were obtained by the condensation of 5-amino-4,6-dichloropyrimidine with 2-amino-1,3-dihydroxypropane or with 2-amino-1,4-dihydroxybutane. The corresponding 6-hydroxy and 6-amino derivatives were obtained by replacement of the chlorine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 262–264, February, 1971.