- new synthetic process for thiamazole
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The present invention relates to a novel synthesis method capable of synthesizing thiamazole by simple heat treatment of methylimidazole and S_8. The present invention provides a safe and low-cost method for synthesizing thiamazole.
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Paragraph 0042-0045
(2021/05/04)
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- Preparation method of 2 -mercapto -1 - methylimidazole
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The invention discloses a preparation method of electronic grade 2-sulfydryl-1-methylimidazole. The method comprises the following steps: (1) a water solution of chloroacetaldehyde dimethyl acetal andmethylamine performs tank closing reaction for 16h at 80 to 85 DEG C; cooling and pressure release are performed; a solvent is used for extraction; the solvent is concentrated; rectification under vacuum is performed to obtain an intermediate of methylaminoacetaldehyde dimethyl acetal; (2) the methylaminoacetaldehyde dimethyl acetal and t-butyl thionitrile react under the boron trifluoride catalysis; condensation reaction is performed at 50 to 70 DEG C to obtain 2-tert-butyl sulfenyl-1-methylimidazole; (3) a solvent is added into the 2-tert-butyl sulfenyl-1-methylimidazole; a catalyst and anorganic solvent are added; reaction is performed at constant temperature; after filtering, filter liquid is concentrated; then, electronic grade water crystallization is performed to obtain the product of 2-sulfydryl-1-methylimidazole. The preparation method has the advantages that the raw material price is low; the environment-friendly effect is achieved; the operation of the synthesis method issimple and convenient; the product quality conforms to application standards of electronic chemicals.
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Paragraph 0020; 0030; 0033; 0034; 0037; 0038; 0041
(2020/07/13)
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- Oxidant/complexing properties of the methimazole (MeImHS)/iodine system towards palladium and gold metals. Crystal structure of the complex cation [PdII(MeImHS)4]2+ balanced by a tetraiodide/iodide mixture
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This paper reports on the oxidative dissolution ability in dichloromethane and water of the methimazole-iodine system towards gold and palladium in powder. This research has a potential application in the recovery process of these metals from electrical and electronic waste equipment (WEEE). The iodine-adduct of methimazole (1-methyl-3H-imidazole-2-thione; MeImHS) oxidises gold and palladium powders in dichloromethane to form the complexes [AuI(MeImHS)2]I3 and [PdII(MeImHS)4](I4)0.73·2(I)0.27. The X-ray crystal structure of the palladium complex shows a square-planar Pd(ii) ion S-coordinated to four MeImHS units with the charge essentially balanced by an unusual tetraiodide I42- with minor amounts of iodide. The oxidative dissolution of palladium in water medium produces the cation [PdII(MeImHS)4]2+. Considering the reaction conditions under which the process was performed ([I2] = 1.14 × 10-3 M, T = 20 °C, pH = 5, reaction time 24 h), the obtained value of 64% of oxidation yields from Pd(0) to Pd(ii) is to be considered satisfactory. No appreciable oxidation was observed for the gold powder in water. The feasibility of recovering palladium from the triiodide salt of the complex cation [PdII(MeImHS)4]2+ was verified by carrying out a two-step reduction process using magnesium powder.
- Isaia, Francesco,Aragoni, Maria Carla,Arca, Massimiliano,Caltagirone, Claudia,Castellano, Carlo,Demartin, Francesco,Garau, Alessandra,Lippolis, Vito,Pivetta, Tiziana
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p. 2652 - 2660
(2020/02/20)
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- Methimazole preparation method
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The invention discloses a methimazole preparation method, which comprises: 1) carrying out an ammonolysis reaction on dimethylchloroacetal and a methylamine methanol solution at a temperature of 125-135 DEG C, adding the alkoxide of an alkali metal after completing the reaction, carrying out a neutralization reaction, filtering, distilling to remove the methanol, and carrying out pressure reducing distillation to obtain an intermediate methylamino dimethoxyethane; and 2) adding sodium thiocyanate and the methylamino dimethoxyethane obtained in the step 1) into purified water, adding hydrochloric acid at a room temperature in a dropwise manner, carrying out a reaction for 12-15 h at a temperature of 50-60 DEG C, carrying out pressure reducing distillation to remove the water after completing the reaction, adding ethyl acetate and a drying agent, carrying out heating reflux for 30 min, carrying out hot filtering, distilling the filtrate until the remaining volume of the ethyl acetate is 1/3, and carrying out cooling crystallization to obtain the methimazole. According to the present invention, the preparation method has advantages of low cost, short route, convenient operation and environmental protection, and the high-quality methimazole can be obtained through the method.
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Paragraph 0033; 0034
(2017/12/09)
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- A 2 - mercapto - 1 - alkyl imidazole of preparation method (by machine translation)
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The invention discloses a 2 - mercapto - 1 - alkyl imidazole synthesis method, which belongs to the technical field of organic synthesis. Imidazole and alkyl halide in the presence of an inorganic base sealing reaction the temperature of the 1 - alkyl imidazole, then dissolved in ether in the solvent, the low temperature by adding 1 - 1.1 equivalent BuLi, then adding 0.9 - 0.95 equivalent powder reflux reaction, after cooling add acetyl chloride to obtain 2 - acetyl thio - 1 - alkyl imidazole; the final 2 - acetyl thio - 1 - alkyl imidazole dissolved in alcohol solvent, adding a catalytic amount of hydrogen chloride or potassium carbonate deprotection, to obtain 2 - mercapto - 1 - alkyl imidazole. The raw material of the invention is cheap, and more friendly to the environment, the advantages of easy operation, the quality of the product in accordance with the electronic chemicals using standard. (by machine translation)
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Paragraph 0024; 0027; 0030; 0033
(2018/01/19)
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- Methimazole synthesizing and purifying method
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The invention discloses a methimazole synthesizing and purifying method, and belongs to the field of medicine synthesis. The method comprises the following steps: carrying out a condensation reaction on methylaminoacetaldehyde polyethylene glycol and ammonium thiocyanate which are used as raw materials in the presence of an acid catalyst and a phase transfer catalyst; and adding saturated salt water after the reaction is completed, uniformly mixing the obtained reaction product and the saturated salt water, adding an organic solvent to carry out extraction, drying and concentrating the obtained organic layer to obtain crude methimazole, heating and dissolving the crude product in a solvent, adding active carbon to decolorize the obtained solution, filtering the solution, and drying the filtered solution to obtain purified methimazole. The method is a preparation method simple to operate and suitable for industrial production.
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Paragraph 0005; 0021; 0024; 0026-0028
(2017/10/07)
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- Preparation method of methimazole
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The invention relates to a preparation method of methimazole. The method specifically comprises the following step: enabling reaction of N-methylimidazole, N-butyllithium and powdered sulfur in an organic solvent to obtain methimazole. The preparation method disclosed by the invention is simple in process, mild in condition, simple to operate, easy for post treatment, applicable for industrialized production, and capable of greatly improving the reaction yield of methimazole.
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Paragraph 0029; 0031; 0032
(2016/10/27)
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- 2-mercapto-1-methyl imidazole industrial production method
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The invention relates to an industrialization production method of antithyroid drug 2-mercapto-1-methylimidazole. The method comprises: (a) reacting vinyl acetate with bromine in absolute ethyl alcohol, regulating a pH value into alkalescence after reaction, obtaining a bromoacetaldehyde diethyl acetal crude product after extraction and desolventization, and directly adding the bromoacetaldehyde diethyl acetal crude product into a next step of reaction; (b) performing aminolysis reaction of bromoacetaldehyde diethyl acetal and methylamine aqueous solution, and after completing reaction, obtaining methylamino acetal through distilling, separating and purifying after extraction and de-watering; (3) dropping hydrochloric acid into aqueous solution of methylamino acetal and potassium rhodanide; removing water in the reaction solution by reduced pressure distillation after reaction, removing a part insoluble in ethyl acetate from the obtained solid, dissolving residual solid into water with pH being 1-2, crystallizing to obtain 2-mercapto-1-methylimidazole with purity higher than 99%, and then vacuum-drying to obtain a finished product. The production method has a short product line, can obtain 2-mercapto-1-methylimidazole with high purity, and has a strong industrialization prospect.
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Paragraph 0024; 0025
(2016/10/08)
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- Methimazole preparation process
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The invention provides a methimazole preparation process including the following steps: 1) with 1-methyl-1,3-2H-imidazole-2-one as a raw material and with cooperation of a reaction solvent, vulcanizing the raw material through a vulcanization reagent to obtain a methimazole crude product; and 2) recrystallizing the crude product obtained in the step 1) to obtain the finished product. With 1-methyl-1,3-2H-imidazole-2-one as the raw material, the common vulcanization reagent is used for vulcanization, and methimazole with light color, high purity and low content of metal ions is obtained; and the whole preparation process is simple, has the advantages of easy operation and lower cost, and is suitable for industrial promotion and application.
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Paragraph 0019; 0020
(2016/11/17)
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- Synthesis and crystal structures of new 1,3-disubstituted imidazoline-2-thiones
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Two methods (MeOH=K2CO3, pyridine=Et3N) were assessed for the introduction of sulfur into the 2-position of 1,3-disubstituted quaternary imidazolium salts 1-9 (Cl, I, BF4, PF6, CH3OSO3 were used as anions) to yield nine 1,3-disubstituted imidazoline-2-thiones 10-18 (1, 10: R1 = CH 3, R2 = CH3; 2, 11: R1 = OCH 2Ph, R2 = CH3; 3, 12: R1 = OCH 3, R2 = CH3; 4, 13: R1 = OCH 3, R2 = OCH3; 5, 14: R1 = NH 2, R2 = CH2Ph; 6, 15: R1 = NCHPh, R2 = CH3; 7, 16: R1 = NH2, R 2 = CH3; 8, 17: R1 = NCHPh, R2 = NCHPh; 9, 18: R1 = NH2, R2 = OCH3). Compounds 11-18 represent N-alkyloxy and N-amino imidazoline-2-thiones, whereas 10 served as reference compound. The first method was advantageous for the conversion 1 → 10 due to faster reaction, whereas in the reaction 2 → 11 considerable amounts of by-products were formed. Pure thiones 11, 14, 16, 17, and 18 were obtained only by the second method. Both methods worked for the synthesis of the methoxy derivatives 12 and 13 from 3 and 4, and the benzylideneamino derivative 15 from 6. 1-Amino-3- methylimidazoline-2-thione (16) was also prepared by hydrolysis of the benzylideneamino derivative 15. Crystal structures of seven 1,3-disubstituted imidazoline-2-thiones were determined by singlecrystal X-ray diffraction. Intermolecular C-H...S contacts were identified and, additionally, N-H...S interactions in aminothiones 14 and 16. The 1H NMR shifts of 10 and 13 were satisfactorily correlated with the Kamlet-Abboud-Taft π* and β parameters in ten solvents. From the lack of correlation with the a parameter and from the C=S bond length (average 1.68 A ) a significant contribution of a mesoionic imidazolium-2-thiolate resonance structure seems unlikely.
- Laus, Gerhard,Kahlenberg, Volker,Wurst, Klaus,Mueller, Thomas,Kopacka, Holger,Schottenberger, Herwig
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p. 1239 - 1252
(2013/12/04)
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- Antithyroid drugs and their analogues protect against peroxynitritemediated protein tyrosine nitration-a mechanistic study
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In this paper, the effect of some commonly used antithyroid drugs and their analogues on peroxynitritemediated nitration of proteins is described. The nitration of tyrosine residues in bovine serum albumin (BSA) and cytochrome c was studied by Western blot analysis. These studies reveal that the antithyroid drugs methimazole (MMI), 6-n-propyl-2-thiouracil (PTU), and 6-methyl-2- thiouracil (MTU), which contain thione moieties, significantly reduce the tyrosine nitration of both BSA and cytochrome c. While MMI exhibits good peroxynitrite (PN) scavenging activity, the thiouracil com-pounds PTU and MTU are slightly less effective than MMI. The S- and Semethylated compounds show a weak inhibitory effect in the nitration of tyrosine, indicating that the presence of a thione or selone moiety is important for an efficient inhibition. Similarly, the replacement of N-H moiety in MMI by N-methyl or N-m-methoxybenzyl substituents dramatically reduces the antioxidant activity of the parent com-pound. Theoretical studies indicate that the substitution of N-H moiety by NMe significantly increases the energy required for the oxidation of sulfur center by PN. However, such substitution in the selenium analogue of MMI increases the activity of parent compound. This is due to the facile oxidation of the selone moiety to the corresponding selenenic and seleninic acids. Unlike N,N'-disubstituted thiones, the corresponding selones efficiently scavenge PN, as they predominantly exist in their zwitterionic forms in which the selenium atom carries a large negative charge.
- Bhabak, Krishna P.,Mugesh, Govindasamy
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experimental part
p. 1175 - 1185
(2010/06/19)
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- Kinetics and mechanism of the nucleophilic cleavage of disulfide bond in 2,2′-dithio-diimidazoles with hydroxide ions
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Kinetics of the cleavage of disulfide bond of dithiobisdisulfides of diimidazoles to their parent imidazoles by hydroxide ion have been investigated spectrophotometrically. Rate equation and other observations suggest that the nucleophilic attack of hydroxide ion on one of the sulfur atoms of disulfide bond is a rate limiting step. This process is accompanied by much slower, parallel reaction with water as a nucleophile. Hence the full kinetic equation for nucleophilic cleavage of 2,2′-dithio-diimidazoles in aqueous alkaline solutions is a two-term equation: -(d[RSSR]/dt) = k1 [RSSR][OHl + k2[RSSR][H2O], where k1 > k2. The mechanism of the reaction is proposed.
- Kurzawa,Suszka
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p. 1487 - 1494
(2008/09/18)
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- New bis(mercaptoimidazolyl)(pyrazolyl)borate ligands and their zinc complex chemistry
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Nine new tripodal NS2 ligands of the bis(mercaptoimidazolyl)(pyrazolyl)borate type with varying 3-R-mercaptoimidazolyl moieties were prepared as their potassium salts. Treatment with zinc salts yielded the complex types L·Zn-Cl, L·Zn-I, L·Zn-ONO2, L·Zn-OClO3 and [L·Zn(imidazole)]ClO4. Attempts at the formation of L·Zn-OH or cationic L·Zn complexes resulted in dismutation and formation of ZnL2 complexes. Hydrolytic destruction yielded one [OZn4(thiooimidazolate)6] complex. The ZnS2NO coordination which is present in the enzyme-substrate complex of alcohol dehydrogenase could be successfully modelled by an [L·Zn(C2H5OH)]+ complex. The L·Zn-X complexes showed very low catalytic activity in the dehydrogenation of 2-propanol or the hydrogenation of p-nitrobenzaldehyde. The new compounds were identified by a total of 12 structure determinations. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Shu, Mouhai,Walz, Rainer,Wu, Biao,Seebacher, Jan,Vahrenkamp, Heinrich
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p. 2502 - 2511
(2007/10/03)
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- Process and device for producing liquid dosage formulations of medicinal compounds on demand from tablets and capsules
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The present invention provides a process for preparing liquid pharmaceutical formulations on demand from tablets and capsules.
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- Energy transfer, electron transfer, and addition reactions of triplet state of 1,3-dihydroimidazole-2-thiones investigated by laser flash photolysis
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The transient absorption bands observed at ca. 400 and 550 nm for 1,3- dihydro-2H-imidazole-2-thione (IT), 1,3-dihydro-1-methyl-2H-imidazole-2- thione (MIT), and 1,3-dihydro-2H-benzimidazole-2-thione (BIT) have been assigned to their triplet states (3IT* 's) by the quenching and sensitizing experiments using laser flash photolysis technique. Short intrinsic triplet lifetimes and relatively high triplet energies have been evaluated as characteristics of 3IT* 's. For electron acceptors, photoinduced electron- transfer reaction occurs via 3IT* 's in the diffusion controlled limit. The nucleophilic character of 3IT* 's was confirmed by changing the substituents of alkenes on the addition reactions. MO calculations indicate that the lowest electronic configurations of both 3IT* and 3MIT* have 3(n,π*) character, while 3BIT* has 3(π,π*) character. The addition reactivity of 3BIT* is slightly higher than those of 3IT* and 3MIT*, which is opposite to the general tendency.
- Alam, Maksudul M.,Ito, Osamu
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p. 339 - 345
(2007/10/03)
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- 2-[(2-Aminobenzyl)sulfinyl]-1-(2-pyridyl)-1,4,5,6- tetrahydrocyclopent[d]imidazoles as a novel class of gastric H+/K+-ATPase inhibitors
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Substituted 2-sulfinylimidazoles were synthesized and investigated as potential inhibitors of gastric H+/K+-ATPase. The 4,5-unsubstituted imidazole series 6-11 and the 1,4,5,6-tetrahydrocyclopent[d]imidazole series 12 were found to be potent inhibitors of the acid secretory enzyme H+/K+- ATPase. Structure-activity relationships indicate that the substitution of 2- pyridyl groups at the 1-position of the imidazole moiety combined with (2- aminobenzyl)sulfinyl groups at the 2-position leads to highly active compounds with a favorable chemical stability. Other substitution patterns in the imidazole moiety result in reducing biological activities. 2-[(2- Aminobenzyl)sulfinyl]-1-[2-(3-methylpyridyl)]-1,4,5,6- tetrahydrocyclopent[d]imidazole (12h, T-776) was selected for further development as a potential clinical candidate. Extensive study on the acid degradation of 12h indicates a mechanism of action different from that of omeprazole, the first H+/K+-ATPase inhibitor introduced to the market.
- Yamada,Yura,Morimoto,Harada,Yamada,Honma,Kinoshita,Sugiura
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p. 596 - 604
(2007/10/03)
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- Equilibrium Studies on the Cleavage of Disulfide Bond in 2,2'-Dithio-Diimidazoles with Iodide Ion in Aqueous Solutions
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The equilibrium of the reaction between 2,2'-dithio-diimidazoles and iodide ion in acidic aqueous solutions was studied spectrophotometrically.Cleavage of -S-S- bond and formation of imidazole-2-thiones and iodine, as reaction products, was observed.Factor analysis and spectra's deconvolution were used for estimation of equilibrium system composition and for determination of equilibrium constants.Occurrence of an additional band (with maximum at 30.000 cm-1) in equilibrium spectra was ascribed to the formation of imidazolethione-I2-charge-transfer complex. Key words: charge transfer, complex compounds, equilibrium constants
- Suszka, A.
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p. 565 - 576
(2007/10/02)
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- PHOTOCHEMISTRY OF AZOLES, PART VII. PHOTOSOLVOLYSIS OF ALKYLMERCAPTOAZOLES. AN APPLICATION TO SOME ACYCLIC MONOTERPENE DERIVATIVES
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Salts derived from 2-alkylmercapto-1-methylimidazoles 1b-e and 3-alkylmercapto-4-methyl-1,2,4-triazoles 2b-d have been found to undergo photochemical heterolytic fission of the S-alkyl bond in aqueous or methanolic solution to give solvolysis-type products.
- Iwasaki, Shigeo
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p. 125 - 138
(2007/10/02)
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- Pesticidal compositions containing phosphoric esters and divalent sulphur compounds
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Pesticidal composition comprising: a pesticidal, phosphoric ester the molecule of which has at least one alkyl group of 1 to 3 carbon atoms, 0.05 to 10% of an agent stabilizing the said ester against decomposition by protonisation, together with adjuvants characterized in that the stabilizing agent comprises at least one sulphur compound containing per molecule at least one divalent sulphur atom of which one valence is bonded to an atom chosen from sulphur, carbon, nitrogen, hydrogen, and metals capable of giving a salt, the other valence being bonded to an atom chosen from hydrogen, the carbon atom already noted, a second carbon atom, the nitrogen atom already noted, a second nitrogen atom, the metal atom already noted in the case of a metal of valence greater than one, a second atom of metal and oxygen when the first valence is not attached to an atom of hydrogen, the proportion of sulphur calculated with reference to the weight of the sulphur compound being between 5 and 99%. Process for stabilizing a phosphoric ester of which the molecule possesses at least one alkyl group containing 1 to 3 carbon atoms characterized in that there is added to the phosphoric ester or to a mixture which contains it, 0.05 to 10% calculated on the weight of the phosphoric acid ester of an agent capable of stabilizing the said phosphoric ester against protonisation and comprising at least one sulphur compound such as that defined thereupon.
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