Synthesis and single-crystal X-ray diffraction studies of 1-β-D-ribofuranosyl-1,2,4-triazole-3-sulfonamide and certain related nucleosides

1-β-D-Ribofuranosyl- 21 , 1-(2-deoxy-β-D-erytftro-pento fur anosyl)- 27 and 1-β-D-arabinofuranosyl- 29 derivatives of 1,2,4-triazole-3-sulfonamide ( 19 ) have been prepared. Glycosylation of the silylated 19 with 1,2,3,5-tetra-0-acetyl-β-D-ribofuranose ( 5 ) in the presence of trimethylsilyl triflate gave the corresponding blocked nucleoside ( 20 ), which on ammonolysis afforded 1-β-D-ribofuranosyl-1,2,4-triazole-3-sulfonamide ( 21 ). Stereospecific glycosylation of the sodium salt of 19 with either 1-chloro-2-deoxy-3,5-di-O-p-toluoyl-α-D-erythro-pentofuranose ( 22 ) or 1-chloro-2,3,5-tri-0-benzyl-α-D-arabinofuranose ( 23 ) provided the corresponding protected nucleosides 26 and 28. Deprotection of 26 and 28 furnished 1-(2-deoxy-β-D-erythro-pentofuranosyl)-1,2,4-triazole-3-sulfonamide ( 27 ) and 1-β-D-arabinofuranosyl-1,2,4-triazole-3-sulfonamide ( 29 ), respectively. 2-0-D-Ribofuranosyl-1,2,4-triazole-3(4H)-thione ( 7 ) and 4-β-D-ribofuranosyl-1,2,4-triazole-3(2H)-thione ( 9 ) were also prepared utilizing either an acid catalyzed fusion of 1,2,4-triazole-3(1H,2H)-thione ( 4 ) with 5 , the reaction of 5 with silylated 4 in the presence of trimethylsilyl triflate, or by ring closure of 4-(2,3,5-tri-0-benzoyl-β-D-ribofuranosyl)thiosemicarbazide ( 10 ) with mixed anhydride and subsequent deacylation. The synthesis of 1-β-D-ribofuranosyl-3-benzylthio-1,2,4-triazole ( 15 ) has also been accomplished by the silylation procedure employing 3-benzylthio-1,2,4-triazole ( 13 ) and 5 to give 1-(2,3,5-tri-0-acetyl-β-D-ribofuranosyl)-3-benzylthio-1,2,4-triazole ( 14 ). Deacetylation of 14 furnished 15 . The structural assignments of 7, 14 and 21 were made by single-crystal X-ray diffraction analysis and their hydrogen bonding characteristics have been studied. The sulfonamido-1,2,4-triazole nucleosides are devoid of any significant antiviral or antitumor activity in cell culture.     

Synthesis and antiviral evaluation of some novel [1,2,4]triazolo[4,3-β][1,2,4]triazole nucleoside analogs

Ribosylation of 3-amino-5H-[1,2,4]triazolo[4,3-b][1,2,4]triazole ( 1 ) with l-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose and stannic chloride resulted in the following protected nucleoside analogs: 3-amino-1-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)[1,2,4]triazolo[4,3-β][1,2,4]triazole ( 4 ), 3-amino-1-(2,3,5-tri-O-benzoyl-α-D-ribofuranosyl)[1,2,4]triazolo[4,3-β][1,2,4]triazole ( 5 ), 3-amino-1-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)[1,2,4]triazolo[4,3-β][1,2,4]triazole ( 5 ), and 3-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl) amino-5H-[1,2,4]triazolo[4,3-b]-[1,2,4]triazole ( 7 ). Compounds 4–6 were deprotected to 3-amino-1-β-D-ribofuranosyl[1,2,4]triazolo[4,3-b][1,2,4]-triazole ( 3 ), 3-amino-1-α-D-ribofuranosyl[1,2,4]triazolo[4,5-b][1,2,4]triazole ( 8 ), and 3-imino-2H-2-β-D-ribo-furanosyl[1,2,4]triazolo[4,3-b][1,2,4]triazole ( 9 ), while 7 could not be deprotected without decomposition. Compounds 1, 4, 6, 7 , and 9 were screened and found to have no antiviral activity.     

Synthesis of 3-Alkyl-6-aryl(arylamino)-7H-[1,2,4]triazolo- [3,4-b][1,3,4]thiadiazines

Starting from 5-alkyl-4-amino-4H-1,2,4-triazole-3-thiols and substituted chloroacetanilides, the corresponding (5-alkyl-4-amino-4H-1,2,4-triazol-3-ylsulfanyl)acetanilides were synthesized. The products underwent intramolecular cyclization in boiling phosphoryl chloride to afford 3-alkyl-6-arylamino-7H-[1,2,4]-triazolo[3,4-b][1,3,4]thiadiazines. 3-Alkyl-6-aryl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine hydrobromides were obtained by reaction of 5-alkyl-4-amino-4H-1,2,4-triazole-3-thiols with substituted phenacyl bromides.     

Amino acids in the synthesis of heterocyclic systems. Synthesis of γ-(5-(1,2,4-Triazinylidene))-α,β-dehydro-α-amino acid derivatives and 6H-pyrido[1,2-d][1,2,4]triazin-6-ones

5-(1,2,4-Triazinyl) substituted enamines 3 react with 5(4H)-oxazolones 4 in acetic anhydride to give acetylated products 5 , while in toluene-acetic acid mixture nonacetylated products 9 are formed. Both types of products were isolated as (E,Z) mixtures. Compounds 5 and 9 rearrange into 6H-pyrido[1,2-d]-[1,2,4]triazin-6-ones 12 by heating in formic acid or in xylene, respectively. Compounds 5 are transformed in the presence of nucleophiles, such as sodium alkoxides or sodium amides via anionic form 10 into corresponding esters 13 and amides 14 of γ-(5-(1,2,4-triazinylidene)) substituted derivatives of α-amino-2-butenoic acid, which exist in 2-(Z),4-(Z) form.     

An efficient one-pot expeditious synthesis of 3-phenyl-1-(6-phenyl-7H-[1,2,4] triazolo[3,4-b] [1,3,4] thiadiazin-3-yl)-1H-pyrazol-5-amines via multicomponent approach

An efficient synthesis of 3-phenyl-1-(6-phenyl-7H-[1,2,4] triazolo[3,4-b][1,3,4]thiadiazin-3-yl)-1H-pyrazol-5-amines was accomplished by a simple, atom-economical, and multicomponent approach. Reaction of 4-amino-5-hydrazinyl-4H-1,2,4-triazole-3-thiol with various phenacyl bromides and benzoylacetonitriles in ethanol and catalytic amount of acetic acid afforded the titled compounds. The structures of newly synthesized compounds were confirmed by their analytical and spectral (IR, ¹H-NMR, ¹³C-NMR, and Mass) data.     

Condensation of 5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione with haloacetic acids

Reactions of triazolethiones with haloacetic acids were studied with 5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione as an example. It was proved for the first time by X-ray diffraction that the cyclocondensation of these compounds proceeds regiospecifically to give 2-(4-methylphenyl)[1,3]thiazolo[3,2-b][1,2,4]triazol-6(5H)-one rather than its isomer 3-(4-methylphenyl)[1,3]thiazolo[2,3-c][1,2,4]triazol-5(6H)-one.     

Facile synthesis and antifungal activity of 3-substituted 4-amino-8-ethoxycarbonylpyrazolo[5,1-c][1,2,4]triazines and pyrazolo[1′,5′:3,4][1,2,4]triazino[5,6-b][1,5]benzodiazepines

The reactions of the pyrazole-5-diazonium salt 3 with malononitrile and ethyl cyanoacetate gave 4-amino-3-cyano-8-ethoxycarbonylpyrazolo[5,1-c][1,2,4]triazine 7 and 4-amino-3,8-bisethoxycarbonylpyrazolo[5,1-c]-[1,2,4]triazine 8 , whose reactions with p-chloroaniline hydrochloride afforded 4-amino-8-ethoxycarbonyl-3-(p-chlorophenyl)amidinopyrazolo[5,1-c][1,2,4]triazine 9 and 4-amino-8-ethoxycarbonyl-3-(p-chlorophenyl)car-bamoylpyrazolo[5,1-c][1,2,4]triazine 10 , respectively. The reactions of 7 and 8 with o-phenylenediamine di-hydrochloride provided 9-ethoxycarbonyl-13H-spiro[benzimidazole-2′(3′H),6(5H)-pyrazolo[1,5′:3,4][1,2,4]tri-azino[5,6-b][1,5]benzodiazepine] hydrochloride 11a and 9-ethoxycarbonyl-6-oxo-13H-5,6-dihydropyrazolo-[1′,5′:3,4][1,2,4]triazino[5,6-b][1,5]benzodiazepine 12 , respectively. The antifungal activity of the above compounds was described.     

Synthesis and anticonvulsant activities of 5-(2-Chlorophenyl)-7H-pyrido[4,3-f][1,2,4]triazolo[4,3-a][1,4]diazepines

A group of 5-(2-chlorophenyl)-10-(substituted)-7H-pyrido[4,3-f][1,2,4]triazolo[4,3-a][1,4]diazepines 7a-c were synthesized by the acid catalyzed reaction of 5-(2-chlorophenyl)-2-hydrazino-3H-pyrido[3,4-e]-[1,4]diazepine ( 6 ) with either trimethyl orthoformate, triethyl orthoacetate or triethyl orthobenzoate, respectively. 5-(2-Chlorophenyl)-7H-pyrido[4,3-f][1,2,4]triazolo[4,3-a][1,4]diazepine ( 7a ) and 5-(2-chlo-rophenyl)-10-methyl-7H-pyrido[4,3-f][1,2,4]triazolo[4,3-a][1,4]diazepine ( 7b ) exhibited good anticonvulsant activity in the subcutaneous metrazol anticonvulsant screen which serves as a model for absence (petit mal) epilepsy.     

Extraction of hydrochloric and nitric acid with 1-{[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl)-1H-1,2,4-triazole and (RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl-methyl)-pentan-3-ol

Extraction of hydrochloric and nitric acid with 1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1H-1,2,4-triazole (propiconazole) and hydrochloric acid with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl-methyl)-pentan-3-ol (tebuconazole) was studied. It is established that extraction of acids proceeds with the formation of monosolvates as an exothermic process. Effective extraction constants of acids are evaluated. By means of the IR and ¹H NMR spectroscopy it was shown that the protonaccepting center of tebuconazole is N⁴ atom of the triazole ring.     

Condensed as-triazines. Synthesis of 7-aryl-8H-[1,4]thiazino[2,3-e]-1,2,4-triazin-3(2H)-one

Ring closure of 6-amino-3-oxo-as-triazine-5-thione with α-haloketones provides the thiazino[2,3-e]-1,2,4-triazines which dehydrate via an unusual pathway to give 7-aryl-8H[1,4]thiazino[2,3-e]-1,2,4-triazin-3(2H)-ones.     

On Triazoles. XXXII. The reaction of 5-amino-1 H-1,2,4-triazolylcarbothiohydrazides with β- and γ-oxo-esters

5-Amino-lH-1,2,4-triazolylcarbothiohydrazides gave β and γ-oxo-esters in boiling ethanol [1,2,4]triazolo- [1,5-d][1,2,4,6]tetrazepine-5-thiones 3 . Analogously ethyl 2-oxocyclohexanecarboxylate provided a mixture of two diastereomeric spiro derivatives 5 and 6 . At 130°, 2-acetonyl-5-methyl-4,5-dihydro-1,3,4-oxadiazole-5-thione ( 8 ) was formed. Ring closure of 3e (R¹ = CH₃, R² = CH₂CH₂COOEt, Q = morpholino) lead to the isomeric pyrrolo[2,1-g][1,2,4]triazolo[1,5-d][1,2,4,6]tetrazepin-8(11H)-one ( 12 ) and pyrrolo[1,2-f][1,2,4]triazolo-[1,5-d][1,2,4,6]tetrazepin-10(7H)-one ( 13 ) derivatives representing two new ring systems.     

2-R-5-Ar(Het)-5,6-dihydro-7H-[1,2,4]triazolo[5,1-b][1,3]thiazin-7-ones

A novel method for synthesis of 2-R-5-Ar(Het)-5,6-dihydro-7H-[1,2,4]triazolo[5,1-b][1,3]thiazin-7-ones by condensation of 3-R-4,5-dihydro-1H-1,2,4-triazole-5-thiones with 3-aryl(heteryl)-2-propenoyl chlorides is proposed.     

A new synthesis of novel 1-aryl-3-heteroaryl-1H-pyrazolo[3,4-b]quinoxalines via a Key Intermediate

The chlorination of the α-hydrazonoester 4 with phosphoryl chloride/pyridine gave 3-[α-(o-chlorophenylhydrazono)methoxycarbonylmethyl]-2-chloroquinoxaline 5 , whose cyclization with 1,8-diazabicyclo[5,4,0]-7-undecene afforded 3-methoxycarbonyl-1-(o-chlorophenyl)-1H-pyrazolo[3,4-b]quinoxaline 6 . The reaction of 6 with hydrazine hydrate provided 3-hydrazinocarbonyl-1-(o-chlorophenyl)-1H-pyrazolo[3,4-b]quinoxaline 7 , whose reactions with methyl and allyl isothiocyanates furnished 3-(2,3-dihydro-4-methyl-3-thioxo-4H-1,2,4-triazol-5-yl)-1-(o-chlorophenyl)-1H-pyrazolo[3,4-b]quinoxaline 2 and 3-(4-allyl-2,3-dihydro-3-thioxo-4H-1,2,4-triazol-5-yl)-1-(o-chloropheny)-1H-pyrazolo[3,4-b]quinoxaline 8 , respectively. Moreover, the reactions of 7 with triethyl orthoformate and orthoacetate gave 1-(o-chlorophenyl)-3-(1,3,4-oxadiazol-5-yl)-1H-pyrazolo-[3,4-b]quinoxaline 9a and 1(o-chlorophenyl)-3-(2-methyl-1,3,4-oxadiazol-5-yl)-1H-pyrazolo[3,4-b]quinoxaline 9b , respectively.     

Synthesis of 1,2,4-triazole, 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole and 1,2,4-triazolo[3,4-b][1,3,4]thiadiazine derivatives of benzotriazole

A novel series of 1-(1-carbonylmethyl-1H-benzotriazole) thiosemicarbazides 3a-e was synthesized and then cyclized with sodium hydroxide to afford 1-(4-substituted-4H-1,2,4-triazole-3-thion-5-yl)methyl-1H-benzotriazoles 4a-e , which were alkylated with ethyl iodide to l-(3-ethylthio-4-substituted-4H-1,2,4-triazol-5-yl)-methyl-1H-benzotriazoles 5b-e . The reaction of 1H-benzotriazol-1-acetic acid hydrazide ( 2 ) with carbon disulphide and potassium hydroxide followed by hydrazine hydrate gave 1-(4-amino-4H-1,2,4-triazole-3-thion-5-yl)methyl-1H-benzotriazole ( 6 ). Its subsequent condensation with carboxylic acids in the presence of phosphorus oxychloride or with phenacyl bromides afforded two series of fused heterocycles namely; 6-substituted-3-[1-(1H-benzotriazole)methyl]-1,2,4-triazolo[3,4-b][1,3,4]thiadiazoles 7a-e and 6-substituted phenyl-3-[1-(1H-benzotriazole)methyl]-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines 8a-e respectively. The structure of the newly synthesized compounds was elucidated by elemental analyses, ir and nmr spectra.     

2-{5-[(1H-1,2,4-三唑-1-基)甲基]-4-苯基-4H-1,2,4-三唑-3-硫基}-1-芳基乙酮类化合物的合成、表征及生物活性测试

通过α-卤代芳基乙酮和5-[(1H-1,2,4-三唑-1-基)甲基]-4-苯基-2H-1,2,4-三唑-3(4H)-硫酮反应, 合成了11个新的2-{5-[(1H-1,2,4-三唑-1-基)甲基]-4-苯基-4H-1,2,4-三唑-3-硫基}-1-芳基乙酮类化合物. 其结构经元素分析, IR, ¹H NMR等确证, 并用X射线单晶衍射测定了化合物6f的晶体结构. 生物活性测试结果表明, 部分化合物具有一定的杀菌活性.     

A new method for the synthesis of novel 1-aryl-3-heteroaryl-1H-pyrazolo[3,4-b]quinoxalines

The reaction of 3-(2,3-dihydro-4-methyl-3-thioxo-4H-1,2,4-triazol-5-ylmethylene)-2-oxo-1,2,3,4-tetrahydroquinoxaline 4 with o-chlorobenzenediazonium chloride gave 3-[α-(o-chlorophenylhydrazono)-2,3-dihydro-4-methyl-3-thioxo-4H-1,2,4-triazol-5-ylmethyl]-2-oxo-1,2-dihydroquinoxaline 6 , whose refluxing in phosphoryl chloride/pyridine afforded 1-(o-chlorophenyl)-3-(2,3-dihydro-4-methyl-3-thioxo-4H-1,2,4-triazol-5-yl)-1H-pyrazolo[3,4-b]quinoxaline 7. The reactions of 6 and 7 with nitrous acid resulted in sulfur extrusion to provide 1-(o-chlorophenyl)-3-(4-methyl-4H-1,2,4-triazol-5-yl)1H-pyrazolo[3,4-b]quinoxaline 8 and 3-[α-(o-chlorophenylhydrazono)-4-methyl-4H-1,2,4-triazol-5-ylraethyl]-2-oxo-1,2-dihydroquinoxaline 9 , respectively.     

Synthesis of 1-[(2-hydroxy-1-(hydroxymethyl)ethoxy)methyl]-1,2,4-triazole-3- and 5-carboxamides

Coupling of trimethylsilyl derivative of methyl 1,2,4-triazole-3-carboxylate with 2-$\text{O}$-(chloromethyl)-1,3-di-$\text{O}$-benzyl glycerol, followed by amination and removal of the protecting groups afforded 1-[(2-hydroxy-1-(hydroxymethyl)ethoxy)methyl]-1,2,4-triazole 3- and 5-carboxamides, 1a and 1b, respectively.     

Synthesis of Derivatives of 4-Hydroxy-2-methyl-3-[2-(5-mercapto-1H-1,2,4-triazol-3-yl)ethyl]quinoline and 2-[2-(4-Hydroxy-2-methyl-3-quinolyl)ethyl]-4H-3,1-benzoxazin-4-one

From 4-hydroxy-2-methylquinoline-3-propionyl chlorides hydrochlorides the corresponding thiosemicarbazides were synthesized. The cyclization of the latter both in alkaline and acidic media furnished 4-hydroxy-2-methyl-3-[2-(5-mercapto-1H-1,2,4-triazol-3-yl)ethyl]quinolines. The reaction of the above propionyl chlorides with anthranilic acid afforded the corresponding 2-[2-(4-hydroxy-2-methyl-3-quinolyl)ethyl]-4H-3,1-benzoxazin-4-ones.     

Conversion of 4-amino-4H-1,2,4-triazole to 1,3-bis(1H-azol-l-yl)-2-aryl-2-propanols and 1-phenacyl-4-[(benzoyl or 4-toluenesulfonyl)-imino]-(1H-1,2,4-triazolium) Ylides

A series of 1,3-bis(1H-azol-1-yl)-2-aryl-2-propanols 17 were synthesized in an one-pot procedure by reacting l-aryl-2-(1H-1,2,4-triazol-l-yl)- or l-aryl-2-(1H-imidazol-l-yl)ethanones with dimethylsulfoxonium methide in the presence of either 1,2,4-triazole or imidazole. The aromatic groups in 17 were either 4-bromo-, 4-chloro-, 2,4-dichloro- or 2,4-difluorophenyl. 4-Amino-4H-1,2,4-triazole was acylated with either benzoyl or 4-toluene-sulfonyl chloride to afford [4-(benzoyl or 4-toluenesulfonyl)amino]4H-1,2,4-triazole. Subsequent alkylations with 4-bromo- or 4-chlorophenacyl bromide produced 1-(4-bromo- or 4-chlorophenacyl)-4-[(benzoyl- or 4-toluenesulfonyl)amino]-1H-1,2,4-triazolium bromides. Neutralizations of these salts provided the corresponding ylides.     

Synthesis of 4-(4-phenyl-3-pyrazolyl)-4H-1,2,4-triazoles

4-(4-PhenyI-3-pyrazolyl)-4H-1,2,4-triazoles and 4-phenyl-5-(4H-1,2,4-triazol4-yl)-3-pyrazolols were prepared by the reaction of formylhydrazine on α-phenyl-α-cyanoacetaldehydes and ethyl α-phenyl-α-cyanoacetates.