- Efficient formation of C–S bond using heterocyclic thiones and arynes
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Phenylthio heterocyclic compounds are widely used because of their diverse biological activities and medicinal prospects. Here, a facile method was reported. An arylation of 1,3,4-oxa(thia)diazol-2-thiones reacting with arynes to build C(aryl)-S bonds in the presence of CsF had good yields and excellent selectivity. The reaction was completed in short time without using expensive reagents and catalysts. Present reaction system is an efficient procedure to process phenylthio heterocyclic compounds and reveals a sustainable method and better application prospects in future organic synthesis.
- An, Yu,Xu, Gang,Cai, Menglu,Wang, Shihui,Wang, Xiao zhong,Chen, Yingqi,Dai, Liyan
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- Synthesis of novel seco-acyclo-N-diazolyl-thione nucleosides analogous derived from acetic acid: characterization, complex formation with ions Pb(II), Hg(II) and antibacterial activity
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Three diazoles namely 5-methyl-1,3,4-oxadiazole -2(3H)-thione, 5-methyl-1,3,4-thiadiazol-2(3H)-thione and 4-amino-5-methyl-2H-1,2,4-triazole-3-thiol were synthesized from acetic acid or ethyl acetate. Seco-acyclo-N-nucleoside analogous was synthesized by condensation of 1,3-benzylidine-glyceryl-2-tosylate with the three diazoles. Structural proof was based upon IR, 1H-NMR, 13C-NMR spectroscopy and MS measurements. The tendency to form complex between 1,3,4-oxadiazole and 1,3,4-thiadiazoles and Pb(II) and Hg(II) ions was achieved, and their structures were assigned by observing some changes in physical properties such as, MP, coloration, Rf (TLC), IR and UV spectroscopy. Most compounds were tested in vitro against Gram-positive and Gram-negative bacteria and showed variable activity. Hg2+ complexes of oxadiazole and thiadiazole derivatives exhibited appreciable antibacterial effect at lower MIC, compatible to the reference vancomycin. Similarly, oxadiazole-nucleoside exhibited high effect on Gram-positive bacteria. Graphic abstract: [Figure not available: see fulltext.]
- Chehrouri, Manel,Othman, Adil A.
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- Synthesis method of 5-methyl-2-mercaptothiadiazole
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The invention discloses a synthesis method of 5-methyl-2-mercaptothiadiazole, which comprises the following steps: in an organic solvent, by using N-acetylhydrazino dithioformate as a substrate, conducting reacting under the catalysis of solid superacid to obtain 5-methyl-2-mercaptothiadiazole. The granular solid superacid adopted in the method has the characteristics of no pollution, no corrosion, easiness in reactant separation and reusability, and is an environment-friendly catalyst.
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Paragraph 0020; 0023-0025; 0026; 0029-0032
(2020/12/31)
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- A simple design of fluorescent probes for indirect detection of β-lactamase based on AIE and ESIPT processes
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A novel fluorescent probe DNBS-CSA is developed for light-up detection of β-lactamase. The probe design is based on an indirect detection approach with three step reactions. β-Lactamase can react with the lactam of its substrate (cefazolin sodium) to prod
- Peng, Lu,Xiao, Lu,Ding, Yiwen,Xiang, Yu,Tong, Aijun
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supporting information
p. 3922 - 3926
(2018/06/21)
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- A 2-mercapto-5-methyl -1, 3, 4-thiadiazole method for the preparation of
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The invention relates to a preparation method of 2-sulfydryl-5-methyl-1, 3, 4-thiadiazole. The preparation method of the 2-sulfydryl-5-methyl-1, 3, 4-thiadiazole, provided by the invention, comprises the following steps of: (1) placing the weighted hydrazine hydrate and ammonium hydroxide into a reaction vessel to be uniformly mixed, dropwise adding carbon disulfide at low temperature, after the dropwise adding operation is ended, stirring and preserving the heat to obtain a water solution of diazanyl dithiocarbamate; (2) adding acetonitrile into the reaction vessel, reacting while stirring, heating, stirring, preserving heat and reflowing to obtain a water solution of 2-sulfydryl-5-methyl-1, 3, 4-thiadiazole aluminum salt; and (3) when the reaction vessel in the step (2) is cooled to be below 40 DEG C, dropwise adding hydrochloric acid for acidifying to obtain a 2-methyl-5-sulfydryl-1, 3, 4-thiadiazole suspension, filtering and washing to obtain milk white crystal powder, namely a crude product of the 2-sulfydryl-5-methyl-1, 3, 4-thiadiazole, and then, purifying and drying the crude product to obtain white crystal powder, namely the 2-sulfydryl-5-methyl-1, 3, 4-thiadiazole. The preparation method has the characteristics of simplicity and convenience in process operation, short reaction time, low production cost and few wastes and pollutants.
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Paragraph 0023-0026
(2017/03/14)
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- Synthesis and biological evaluation of nonsymmetrical aromatic disulfides as novel inhibitors of acetohydroxyacid synthase
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46 Novel nonsymmetrical aromatic disulfides containing [1,3,4]thiadiazole or [1,3,4]oxadiazole groups were synthesized and their biological activities were evaluated as inhibitors of acetohydroxyacid synthase (AHAS, EC 2.2.1.6). Besides their strong in vitro inhibition against plant AHAS, compounds 3e and 3f also display 80-100% post-emergence herbicidal activities in greenhouse bioassay at 1500 g/ha dosage. The assay of exogenous branched-chain amino acids supplementation on rape root growth of 3e suggests that the herbicidal activity has relationship with AHAS inhibition.
- Li, Zai-Shun,Wang, Wei-Min,Lu, Wei,Niu, Cong-Wei,Li, Yong-Hong,Li, Zheng-Ming,Wang, Jian-Guo
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supporting information
p. 3723 - 3727
(2013/07/25)
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- Thiadiazole Which can be used as a Vulcanization Accelerator and Method for Obtaining Same
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A thiadiazole of formula (I):
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Paragraph 0061-0071
(2013/03/26)
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- Green synthesis of 5-substituted-1,3,4-thiadiazole-2-thiols as new potent nitrification inhibitors [1]
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(Chemical Equation Presented) A fast, efficient synthesis of 5-substituted-1,3,4-thiadiazole-2-thiols was successfully developed, assessed using green chemistry matrices, and compounds were screened for their in vitro nitrification inhibitory activity. The greener method was superior with higher energy efficiency, E(nvironmental) factor, atom economy, atom efficiency, carbon efficiency, and reaction mass efficiency.
- Saha, Ajoy,Kumar, Rajesh,Kumar, Rajendra,Devakumar
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experimental part
p. 838 - 845
(2010/10/04)
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- UV-induced transformations of matrix-isolated 1,3,4-thiadiazole-2-thiones
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Monomers of 5-mercapto-1,3,4-thiadiazole-2-thione (bismuthiol) were studied using an experimental matrix-isolation technique as well as by carrying out theoretical quantum chemical calculations. The calculations, performed using the quadratic configuration interaction method with single and double excitations (QCISD)/6-31++G(d,p)//DFT(B3LYP)/ 6-311 ++G(2d,p), predict that the thione-thiol tautomer of bismuthiol should be significantly (by more than 19 kJ mol-1) more stable than other tautomeric forms. Accordingly, only the signatures of the thione-thiol tautomer were observed in the FT-IR spectrum of bismuthiol, recorded directly after deposition of an Ar matrix. UV (l> 320 nm) irradiation induced the conversion of the thione-thiol tautomer into the dithiol form. Analogous investigations were carried out for two related compounds: 5-methyl-1,3,4-thiadiazole-2-thione and 5-methylthio-1,3,4-thiadiazole-2-thione. For these two species, only the thione tautomeric forms were observed after deposition of Ar matrices. These tautomers were predicted (by QCISD calculations) to be more stable (by at least 19kJmol-1) than other tautomeric forms. Upon UV irradiation, the most stable thione forms of these compounds were transformed into the corresponding thiol tautomers. Direct observation of the thione! thiol phototautomeric processes provides a clear proof that intramolecular proton transfer reaction can occur in molecules, such as bismuthiol, in spite of the increased NH...S distance, in comparison to other phototautomerizing species studied so far. All the isomers of the studied compounds (substrates and products of the photoreactions) were identified by comparison of their IR spectra with the spectra calculated at the DFT(B3LYP)/6-311 ++G(2d,p) level of theory for possible isomeric structures. Copyright
- Rostkowska, Hanna,Lapinski, Leszek,Nowak, Maciej J.
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experimental part
p. 56 - 66
(2010/07/08)
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- Instant degradation of plastics into soluble non-toxic products
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The present invention describes novel, cost-effective and rapid processes suitable for degradation and recycling of specially designed plastics, which are defined as instantly degradable synthetic polymeric plastics having the characteristics and properties of conventional forms of plastics. These novel plastic products are made from a variety of compositions of polymers and their compatible nontoxic modifiers. The resulting novel instant degradable plastic products retain latent solubility properties which are triggered upon mild chemical processes of the present invention, thus enabling cost effective and facile recycling of plastic refuge.
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- A rapid one-pot synthesis of 5-substituted-2-mercapto-1,3,4-thiadiazoles using microwaves
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A rapid one-pot synthesis is described for 5-substituted-2-mercapto-l,3,4-thiadiozoles 2a-d under microwave irradiation starting from thioamides la-d.
- Kidwai, Mazaahir,Bhushan, Kumar Ranjan
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p. 427 - 428
(2007/10/03)
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- Kinetics and mechanism of decomposition of cefazolin ester in phosphate buffer solution
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We evaluated the rate and mechanism of decomposition of cefazolin methyl ester (Λ3 ester) in phosphate buffer (pH 8.4). The decomposition of Λ3 ester proceeded simultaneously via 3 pathways. The first pathway is production of Λ2 ester (rate k12) by isomerization and production of Λ2 acid (k23) by hydrolysis of the Λ2 ester. The second pathway is the cleavage reaction of the β-lactam ring and simultaneous elimination of the substituent at position 3 (k14). The third pathway is production of Λ3 acid (k15) by hydrolysis of the carboxylic ester at position 4. Kinetic analysis of each pathway was performed. The reaction rate constant from Λ2 ester to Λ2 acid (k23) was the highest, and the reaction rate constant for the production of Λ2 ester by isomerization (k12) was similar to that for the elimination of the position 3 substituent by cleavage of the β- lactam ring (k14). The rate of production of Λ3 acid by hydrolysis of the position 4 carboxylic ester was the lowest. These results show that Λ3 ester decomposition under a basic condition predominantly occurs through cleavage reaction of the β-lactam ring and Λ2 ester production by isomerization. Since the production of Λ2 acid markedly depended on the production of Λ2 ester by isomerization, Λ2 ester production is the rate- limiting step of this pathway.
- Yamazaki, Yutaka,McEntagart, John,Shinozaki, Katsuhiko,Yazawa, Hisatoyo
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p. 599 - 601
(2007/10/03)
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- Cephalosporin compounds and antibacterial agents
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Cephalosporin compounds of the formula (I): STR1 wherein R1 and R2 may be the same or different and are a hydrogen atom or a lower alkyl group of 1-5 carbon atoms and A is a hydrogen atom or a nucleophilic compound residue or pharmacologically acceptable salts thereof have excellent antibacterial activity against Gram positive and Gram negative microorganisms.
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- Cephalosporin derivatives and bactericides containing the same
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Cephalosporin compounds represented by the following formula (I) and pharmaceutically acceptable salts thereof have a broad bactericidal spectrum against various pathogenic bacteria including Psuedomonas aeruginosa and are useful as bactericidal remedies for pathogenic diseases of human and animals: STR1 wherein A represents an unsubstituted or substituted pyridylthio group of a formula (I-1); STR2 or an unsubstituted or substituted pyridiniumthio group of a formula (I-2): STR3 or an unsubstituted or substituted pyridinium group of a formula (I-3); STR4 or a 5- or 6-membered heterocyclicthio or bicycloheterocyclicthio group of a formula (I-4):
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- REDUCTIVE CLEAVAGE OF SYMMETRICAL DISULFIDES WITH HYDRAZINES
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An efficient method for the reductive cleavage of symmetrical disulfides with hydrazines is described.
- Maiti, Samarendra N.,Spevak, Paul,Singh, Maya Prakash,Micetich, Ronald G.,Reddy, A. V. Narender
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p. 575 - 582
(2007/10/02)
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- Acylamino-cephem-carboxylic acids containing an amidino or guanidino group in the molecule
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Acylamino-cephem-carboxylic acids of the formula I STR1 in which R1, R2 and R3 represent hydrogen or alkyl, R1 and R2 or R2 and R3 together may form an alkylene radical which may be substituted, X represents a single bond or NH, A represents a phenylene or thienylene radical which may be substituted, Y represents a single bond or oxygen and Z represents a 5- or 6-membered ring which may be substituted and which may be bound to an anellated ring system, and their physiologically tolerated salts and esters, a process for preparing these compounds and preparations containing them.
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- 7-[α-(2-Aminomethyl-1-cyclohexenyl)-acetamido]-3-heterocyclic thiomethyl-3-cephem-4-carboxylic acids
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7-[α-(2-Aminomethyl-1-cyclohexyl)-acetamido]-3-heterocyclic thiomethyl-3-cephem-4-carboxylic acids, and their nontoxic, pharmaceutically acceptable salts and their Schiff bases, as made by reaction of salicylaldehyde with the free amino group, are valuable as antibacterial agents and are particularly valuable as therapeutic agents in poultry and animals, including man, in the treatment of infectious diseases caused by many Gram-positive and Gram-negative bacteria.
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