Selenium heterocycles XXV. Synthesis of thieno[3,4-d][1,2,3]-thiadiazole,selenolo[3,4-d][1,2,3]thiadiazole and pyrrolo[3,4-d][1,2,3]-thiadiazole. Three novel ring systems

Starting from the readily available 4-bromomethyl-5-benzoyl-1,2,3-thiadiazole and 5-bromomethyl-4-benzoyl-1,2,3-thiadiazole; thieno[3,4-d][1,2,3]thiadiazole, selenolo[3,4-d][1,2,3]-thiadiazole and pyrrolo[3,4-d][1,2,3]thiadiazole were synthesized in good yield.     

New 1,2,3-selenadiazole and 1,2,3-thiadiazole derivatives

New 1,2,3-thiadiazole and 1,2,3-selenadiazole derivatives, 14-23, were prepared from the ketones 1-5 via the corresponding semicarbazones or hydrazones 6-12. The Hurd-Mori and Lalezari methods were used, respectively, for the preparation of these 1,2,3-thiadiazole and 1,2,3-selenadiazole derivatives. The intermediate 13 was also trapped, separated and fully characterized. These derivatives are important for photocrosslinking processes and due to their potential biological activity.     

Synthesis and structure of the new mesoionic 1-thiasydnonimine system

Synthesis of 5-acylimino-3-methyl-1,2,3-thiadiazole 4 is described and its molecular structure is confirmed by NMR and X-Ray diffraction analysis.     

Phosphorus pentachloride-induced transformation of (1,2,3-thiadiazol-5-yl)hydrazones of acetophenone

Russian Chemical Bulletin - Reactions of (4-ethoxycarbonyl-1,2,3-thiadiazol-5-yl)hydrazones of acetophenone with PCl5 led to transformation of the 1,2,3-thiadiazole moiety involving four atoms of...     

Synthesis of 1,2,3-thiadiazolo[4,5-d] pyridazines,A new heterocyclic ring system

A method was developed for the synthesis of 5-carbethoxy-4-formyl-1,2,3-thiadiazole (I), its isomer (II); 5-benzoyl-4-formyl-1,2,3-thiadiazole (III), and its isomer (IV). It was demonstrated that although compounds I, III and IV with hydrazine gave 7H-1,2,3-thiadiazolo[4,5-d]-pyridazin-7-one (XXII), 7-phenyl-1,2,3-thiadiazolo[4,5-d]pyridazine (XXIII) and 4-phenyl-1,2,3-thiadiazolo[4,5-d]pyridazine (XXV), respectively; however, compound I gave its corresponding hydrazone (XXIV).     

The Synthesis And Crystal Structure Of 3-[5-Methyl-1-(4-Methylphenyl)-1,2,3-Triazol-4-yl]-s-Triazolo[3,4-b]-1,3,4-Thiadiazole

Likewise the 1,3,4-thiadiazole nucleus which incorporates an N-C-S linkage exhibits a large number of biological activities^[1]. The fused 1,3,4-triazolo[3,4-b]-1,3,4-thiadiazoles derivatives show various biological effects, such as antifungal^[2], antibacterial, hypotensive and CNS depressant activities^[3]. The novel 3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazolo[3,4-b]-1,3,4-thiadiazole 6 have been synthesized by the condensation of 4-amino-5-mercapto-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazole 5 with formic acid in the presence of phosphorus oxychloride. The compound 5 was prepared from 4 that was prepared from 1 throng 2 and 3. Recently, we obtained the crystal structure of the novel compound 3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazolo[3,4-b]-1,3,4-thiadiazole, C₁₄H₁₂Cl₃N₇S, Mr=416.72, Crystallizes in the triclinic space group with unit cell parameters a=9.049(2), b=10.486(3), c=10.843(2)Å, α=116.79(2), β=93.83(2), γ-100.64(3)°. V=889.3(4)ų, Z=1, Dx-0.778 Mgm^-3. The final R was 0.0535.     

Chemistry of 1,2,3-thiadiazole. IV. Synthesis of [1]benzoxepino-[3,4-d][1,2,3]thiadiazole, [1]benzothiepino-[3,4-d][1,2,3]thiadiazole, [1]benzoxepino[4,3-d][1,2,3]thiadiazole, [1]benzoxepino[4,3-d]oxazole and [1]benzoxepino[4,3-d]oxazole. Four novel heterocycles

Starting from the readily available 4-bromomethy-5-carbethoxy 1,2,3-thiadiazole (V), 5-bromomethy-4-carbethoxy-1,2,3-thiadiazole (IX) and ethyl 2-aryl-5-bromomethyloxazole-4-carboxylate (XIV), 4,10-dihydro-10-oxo[1]benzoxepino[3,4-d][1,2,3]thiadiazole (Ia), 4,10-dihydro-10-oxo[1]benzothiepino[3,4-d][1,2,3]thiadiazole (Ib), 4,10-dihydro-4-oxo[1]benzothiepino[4,3-d] [1,2,3]thiazole (II), 2-aryl-4,10-dihydro-4-oxo[1]benzoxepino[4,3-d]oxazoles (XIXa-XIXc) and 2-aryl-4,10-dihydro-4-oxo[1]benzothiepino[4,3-d]oxazoles (XIXd-XIXf) were prepared.     

Synthesis,Crystal Structure and Biological Activity of N-tert-butyl-N-(4-methyl-1,2,3-thiadiazole)-5-yl-N’-(4-methyl-1,2,3-thiadiazole)-5-formyl-N’-3,5-dichloropyridin-2-yl-diacylhydrazine

The title compound N-tert-butyl-N-(4-methyl-1,2,3-thiadiazole)-5-yl-N'-(4-me-thyl-1,2,3-thiadiazole)-5-formyl-N'-3,5-dichloropyrid-2-yl-diacylhydrazines (C18H17Cl2N7O3S2, Mr = 514.41) has been synthesized by the reaction of N-tert-butyl-N'-3,6-dichloropyridine-2-formyl hydrazine with 4-methyl-1,2,3-thiadiazole-5-carbonyl chloride and triethylamine, and its structure was characterized by 1H NMR, HR MS, and single-crystal X-ray diffraction. The crystal of the title compound belongs to monoclinic, space group C2/c with a = 27.726(8), b = 11.045(3), c = 14.507(4), β = 96.758(4)°, Z = 8, V = 4412(2) 3, Dc = 1.549 g/cm3, μ = 0.521 mm-1, F(000) = 2112, R = 0.0405 and wR = 0.1153. X-ray analysis indicates that all rings are non-planar in this molecule. The bioassay results indicate that both the title compound and the positive control RH-5992 have weak fungicide activities, while the title compound has good insecticidal activity against Plutella xylostella L. and no insecticidal activity against Culex pipiens pallens.     

3-(4-Thiocarbamoyl-1,2,3-triazol-1-yl)benzo-15-crown-5: synthesis and properties

A reaction of 1,2,3-thiadiazole-4-carbaldehyde with 3-aminobenzo-15-crown-5 involves the Cornforth rearrangement of the 1,2,3-thiadiazole ring, which leads to 1,2,3-triazole-4-carbothioamide containing the benzocrown ether substituent in position 1 of the triazole ring. Reversible formation of the isomeric thiadiazole occurs in aprotic nonpolar solvents such as deuterated chloroform. These compounds are suitable for extraction of α-amino acids from an aqueous phase.     

Hetaryl 1,2,3-Thiadiazolyl Sulfides

The synthesis of hetaryl 1,2,4-thiadiazolyl sulfides has been carried out by nucleophilic substitution of the chlorine atom in 5-chloro-1,2,3-thiadiazole by mercaptoheterocycles.     

Reactions of Ethyl 5-Methyl-4-(1,2,3-thiadiazol-4-yl)furan-2-carboxylate with Selected Bases

Russian Journal of General Chemistry - The reactions of 5-methyl-4-(1,2,3-thiadiazol-4-yl)furan-2-carboxylic acid ethyl ester with some bases have been studied. The opening of 1,2,3-thiadiazole...     

1,2,3-噻二唑-4-乙酰胺(吗啉)类衍生物的合成与生物活性

以双乙烯酮为起始原料, 设计并合成了一系列新颖的1,2,3-噻二唑-4-乙酰苯胺(吗啉)类化合物, 通过元素分析、红外光谱、核磁共振氢谱和质谱对其结构进行了表征. 生物活性测试结果表明,部分化合物具有一定的抗TMV活性、 植物生长调节活性和杀菌活性.     

Formation of a stable selenirane via cycloaddition of selenirene

A novel and stable selenirane derivative was obtained by photolysis of 6,6,8,8-tetramethyl-2-selena-3,4-diaza-7-oxabicyclo[3.3.0]octa-1(5),3-diene in furan as the [2+4] adduct of selenirene intermediate. Similarly 1,2,3-thiadiazole in furan gave corresponding thiirane.     

Synthesis and Biological Activity of α-Substituted 1,2,3-Thiadiazole-4-Acetic Acid Derivatives

Compounds containing 1,2,3-thiodiazole ring were reported to posses fungicidal¹, herbicidal² and growth regulation properties³. For example, N-phenyl-N'-1,2,3-thiadizazol-5-yl-urea (Thidiazuron, Dropp) has been used as a cotton defoliant⁴, herbicide and was also found to exhibit cytokinin-like activity in bioassay systems. The compound was more effective than Zeatin⁵ and 6-BA⁶. Because the synthesis of 1,2,3-thiodiazole ring is difficult,compounds containing 1,2,3-thiadiazole ring are relatively seldom reported. Herein, we report the synthesis of a novel series of α-substituted-1,2,3-thiadiazole-4-acetic acid derivatives.     

Synthesis of 6-(1-Aryl-5-methyl-1,2,3-triazol-4-yl)-3-(4-Pyridyl)-s-Triazolo[3,4-b]-l,3,4-Thiadiazoles

A survey of literature¹ revealed that s-triazolo[3,4-b]-1,3,4-thiadiazole, an interesting fused system of s-triazole and 1,3,4-thiadiazole rings, has received much attention during recent years on account of its prominent utilizations as antifungal, antiinflammatory, antiviral, analgesic and anthelmintic agents probably resulting from its planner and compact structure. Our earlier work on the synthesis of this class of heterocycles showed antibacterial, herbicidal and plant growth regulative properties^2-3 for the compounds. 1,2,3-Triazole derivatives have found their wide use in medicine, agriculture and industry^4-5. Incorporation of 1,2,3-triazole moiety into the 6-position of this ring system may lead to achieving compounds of better biological activities. In view of the above findings coupled with scanty reports on these condensed compounds carrying 6-heterocyclic groups, we wish to report here the condensation of 4-amino-5-mercapto-3-(4-pyridyl)-l,2,4-triazole(2) with 1-aryl-4-carboxy-5-methyl-1,2,3-triazoles(1_a-j) as a part of our continuing interest in this area.     

2-Azido-1,3,4-thiadiazoles, 2-Azido-1,3-thiazoles,and Aryl Azides in the Synthesis of 1,2,3-Triazole-4-carboxylic Acids and Their Derivatives

Diazotization of 2-amino-1,3,4-thiadiazoles gave 1,3,4-thiadiazole-2-diazonium sulfates which were converted to 2-azido-1,3,4-thiadiazoles. The latter reacted with ethyl acetoacetate in the presence of sodium methoxide in methanol to produce 1-(5-R¹-1,3,4-thiadiazol-2-yl)-5-R²-1H-1,2,3-triazole-4-carboxylic acid derivatives. The reactions of 2-azido-5-methyl-1,3,4-thiadiazole and 2-azido-1,3-thiazole with ethyl 3-(1,3-benzodioxol-5-yl)-3-oxopropanoate led to the formation of 1,2,3-triazole ring under milder conditions (K₂CO₃, DMSO). Various 1,2,3-triazole-4-carboxylic acid derivatives were synthesized.     

含1,2,3-噻二唑的邻甲酰胺基苯甲酰胺类化合物的合成、晶体结构与生物活性

以取代邻氨基苯甲酸为起始原料, 设计并合成了一系列未见文献报道的含1,2,3-噻二唑的邻甲酰胺基苯甲酰胺类化合物. 所有化合物的结构均经元素分析和1H NMR确证, 并且采用X射线单晶衍射分析方法测定了化合物7g的结构. 初步的生物活性试验结果表明, 部分化合物具有一定的杀菌活性.     

Attempted reduction of 1,2,3-thiadiazole-4-carboxylates with samarium/iodine in methanol. Unexpected ring enlargement to 1,2,5-trithiepan-4,6-dicarboxylates

When stirred with powdered samarium and iodine in methanol at ice-cold temperature, ethyl 1,2,3-thiadiazole-4-carboxylate 5 underwent unusual reduction involving the dimeric ring enlargement with a sulfur addition, giving dimethyl 1,2,5-trithiepan-4,6-dicarboxylates 7a,b as a cis/trans-isomeric mixture in acceptable yield. The 1,2,3-thiadiazole ring of 5 proved to resist reduction by ordinary reducing agents, where the only choice in most cases was either recovery of the unchanged substrate or decomposition to an intractable mixture of unidentified products and tar.     

Synthesis and bioactivity of N-tert-butyl-N′-acyl-5-methy 1-1,2,3-thiadiazole-4-carbohydrazides

A series of novel N-tert-butyl-N′-acyl-5-memyl-l,2,3-thiadiazole-4-carbohydrazides were designed and synthesized.Their structures were characterized by melting points,~1H NMR,IR,ESI-MS,and elemental analysis.The bioassay tests indicated that compound 7o exhibited excellent direct anti-TMV activity and induction activity in vivo at 50μg/mL,which was better than that of Ninamycin and tiadinial.Our studies indicated that 1,2,3-thiadiazole was an active substructure for novel pesticide development.     

Carbon-13 Nmr spectra of 1,2,3-thiadiazoles

Natural abundance ¹³C nmr spectra are reported for 1,2,3-thiadiazole and nine derivatives. The spectra are discussed in terms of α- and β-effects of substituent groups and compared with corresponding spectra of alkene and benzene derivatives. ¹³C nmr spectra of four 1,3,4-thiadiazoles are presented. Spectral data indicate that in dimethylsulfoxide solution 2-mercapto-5-methyl-1,3,4-thiadiazole exists predominantly as the thione tautomer.