- Diazotisation Mechanism of Heteroaromatic Amines. Diazotisation of 2-Aminothiazole as an Equilibrium
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The rate of diazotisation of 2-aminothiazole was measured in 65 to 75 percent (w/w) aqueous H2SO4.The kinetic solvent isotope effect of the diazotisation in 72 percent D2SO4/D2O was determined (kH/kD = 5.8+/-0.2).These data are consistent with a mechanism in which the 2-aminothiazole, protonated at the ring N-atom, but not at the NH2 group, is attacked by the NO+ ion.The reaction does not go to completion, but to an equilibrium.The equilibrium concentration of the diazonium ion was determined in 30, 50, 70, and 90 percent (w/w) H2SO4 at three initial concentrations of reagents (0.001, 0.01, and 0.1 M).The final concentrations of the reagents and the diazonium ion are consistent with a reversible process.This is the first diazotisation for which quantitative evidence for equilibration has been found.In the very large range of acidities used (H0 = -1.73 to -9.01), it was not possible to calculate meaningful equilibrium constants that are independent of the acidity.
- Diener, Heinz,Guelec, Bilge,Skrabal, Peter,Zollinger, Heinrich
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Read Online
- Synthesis of 6-membered-ring fused thiazine-dicarboxylates and thiazole-pyrimidines via one-pot three-component reactions
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A facile and efficient one-pot three-component reaction method for the synthesis of thiazine-dicarboxylates is reported. Reaction of an isocyanide and dialkyl acetylenedicarboxylate with 2-amino-4H-1,3-thiazin-4-one derivatives containing both an acidic proton and an internal nucleophile gave the products in good yields of 76–85%. The reactivity of dialkyl acetylenedicarboxylates was further tested in the synthesis of thiazole-pyrimidines where a two-component reaction of 2-aminothiazole with dialkyl acetylenedicarboxylates was successfully converted to a more efficient three-component reaction of a thiourea, α-haloketone and dialkyl acetylenedicarboxylate (DMAD/DEtAD) to give thiazole-pyrimidines in good yields of 70–91%.
- Bode, Moira L.,Coyanis, Elena Mabel,Fernandes, Manuel A.,Fish, Muhammad Q.,Mohlala, Reagan L.
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- SUBSTITUTED IMIDAZOLES FOR THE INHIBITION OF TGF-BETA AND METHODS OF TREATMENT
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This disclosure relates to low molecular weight substituted imidazoles that inhibit the TGF-b signaling pathway. More specifically, this disclosure relates to methods of using said imidazoles for the treatment of diseases related to the TGF-b signaling pathways including, but not limited to, atherosclerosis, Marfan syndrome, Loeys-Dietz syndrome, obesity, diabetes, multiple sclerosis, keratoconus, idiopathic pulmonary fibrosis, Alzheimer's Disease, chronic kidney disease, and scleroderma.
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Paragraph 0079
(2020/03/15)
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- Novel synthesized SLC-0111 thiazole and thiadiazole analogues: Determination of their carbonic anhydrase inhibitory activity and molecular modeling studies
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In the presented work, we report the design and synthesis of novel SLC-0111 thiazole and thiadiazole analogues (11a–d, 12a–d, 16a–c and 17a–d). A bioisosteric replacement approach was adopted to replace the 4-fluorophenyl tail of SLC-0111 with thiazole and thiadiazole ones, which were thereafter extended with lipophilic un/substituted phenyl moieties. All the newly synthesized SLC-0111 analogues were evaluated in vitro for their inhibitory activity towards a panel of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) isoforms (hCA I, II, IX and XII), using a stopped-flow CO2 hydrase assay. All the examined isoforms were inhibited by the primary sulfonamide derivatives (11a–d and 12a–d) in variable degrees with the following KI ranges: 162.6–7136 nM for hCA I, 9.0–833.6 nM for hCA II, 7.9–153.0 nM for hCA IX, and 9.4–94.0 nM for hCA XII. In particular, compounds 12b and 12d displayed 5.5-fold more potent inhibitory activity (KIs = 8.3 and 7.9 nM, respectively) than SLC-0111 (KI = 45 nM) towards hCA IX. Molecular docking study was carried out for 12d within the hCA IX (PDB 3IAI) active site, to justify its inhibitory activity.
- Abo-Ashour, Mahmoud F.,Eldehna, Wagdy M.,Nocentini, Alessio,Ibrahim, Hany S.,Bua, Silvia,Abdel-Aziz, Hatem A.,Abou-Seri, Sahar M.,Supuran, Claudiu T.
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p. 794 - 802
(2019/04/13)
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- Hg2+ induced hydrolysis of thiazole amine based Schiff base: Colorimetric and fluorogenic chemodosimeter for Hg2+ ions in an aqueous medium
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Simple pyrene-based chemosensors 1 to 3, were synthesized from pyrene-1-carboxaldehyde and they were characterized using various spectroscopic techniques like UV–Vis, FT-IR, Mass, 1H NMR and 13C NMR. Among synthesized receptors, the receptor 1 shows high selectivity towards Hg2+ ions. Further, the high selectivity of receptor 1 towards Hg2+ ions in the presence of various other interfering metal ions like Ni2+, Zn2+, Mn2+, Co2+, Cu2+, Cr3+, Fe3+, Al3+, Ag+, Fe2+, Cd2+, Mg2+, Pb2+, Ca2+, Na+, K+ was confirmed by UV–Vis and fluorescence methods. The detection limit for Hg2+ ions was found to be 0.270 μM. The chemodosimetric irreversible hydrolysis of the receptor 1 in the presence of Hg2+ was studied by UV/Vis, fluorescence, FT-IR, LC-MS, 1H NMR and theoretical DFT study. Further, the real life applications of receptor 1 for the determination of Hg2+ ions were demonstrated by UV–Vis method.
- Tekuri, Venkatadri,Sahoo, Suban K.,Trivedi, Darshak R.
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- Imidazole-thiazole coupled derivatives as novel lanosterol 14-α demethylase inhibitors: ionic liquid mediated synthesis, biological evaluation and molecular docking study
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A novel series of imidazole-thiazole coupled derivatives (7a–7q) were synthesized using Green protocol and identified by different spectroscopic techniques. The synthesized derivatives (7a–7q) were evaluated for their in vitro antifungal activity against the six fungi strains. The compounds 7j and 7k exhibited the most promising antifungal activity. The compound 7k exhibited extremely high antifungal activity against C. albicans, C. glabrata, F. oxysporum, A. flavus, A. niger, and C. neoformans with MIC80 values of 0.2, 0.2, 20, 35, 40, and 5 μg/ml respectively. The mode of action of the most promising antifungal compounds 7j and 7k was established by ergosterol extraction and quantitation assay. From the ergosterol extraction and quantitation assay it was found that the compounds 7j and 7k act by inhibition of ergosterol biosynthesis in C. albicans. The molecular docking study revealed the high spontaneous binding ability of the tested compounds to the active site of lanosterol 14α-demethylase, which proves that the tested compounds inhibit the synthesis of lanosterol 14α-demethylase. The synthesized compounds were analyzed for ADMET properties to establish oral drug like behavior and shows satisfactory results. To establish the antifungal selectivity and safety, the most active compounds were further tested for cytotoxicity against human cancer cell lines HeLa and K-562 and were found to be non-cytotoxic in nature. The in vivo acute oral toxicity study was performed for the most active compounds and results indicate that the compounds are non-toxic in nature.
- Nikalje, Anna Pratima G.,Tiwari, Shailee V.,Sarkate, Aniket P.,Karnik, Kshipra S.
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p. 592 - 606
(2017/11/06)
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- Metal-free C(sp2)-H functionalization of azoles: K2CO3/I2-mediated oxidation, imination, and amination
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The direct C2-H oxidation and imination of a wide variety of azoles was achieved by using a commercially available simple K2CO3/I2 reagent combination. The iodinated azole adduct, produced via the in situ generation of N-heterocyclic carbene, is the key intermediate for C2-H oxidation, imination, and amination of azoles. Significantly, these reactions proceed under mild conditions with high to excellent yields, are scalable to large quantity and exhibit a broad substrate scope. Interestingly, this direct C2-H imination method allowed us to access various pharmacologically active N6-alkyl or N6-aryl substituted benzimidazoquinazolinone scaffolds through intramolecular C-H imination in a sequential one-pot reaction.
- Das, Ranajit,Banerjee, Mainak,Rai, Rakesh Kumar,Karri, Ramesh,Roy, Gouriprasanna
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p. 4243 - 4260
(2018/06/22)
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- Prebiotic selection and assembly of proteinogenic amino acids and natural nucleotides from complex mixtures
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A central problem for the prebiotic synthesis of biological amino acids and nucleotides is to avoid the concomitant synthesis of undesired or irrelevant by-products. Additionally, multistep pathways require mechanisms that enable the sequential addition of reactants and purification of intermediates that are consistent with reasonable geochemical scenarios. Here, we show that 2-aminothiazole reacts selectively with two- and three-carbon sugars (glycolaldehyde and glyceraldehyde, respectively), which results in their accumulation and purification as stable crystalline aminals. This permits ribonucleotide synthesis, even from complex sugar mixtures. Remarkably, aminal formation also overcomes the thermodynamically favoured isomerization of glyceraldehyde into dihydroxyacetone because only the aminal of glyceraldehyde separates from the equilibrating mixture. Finally, we show that aminal formation provides a novel pathway to amino acids that avoids the synthesis of the non-proteinogenic α,α-disubstituted analogues. The common physicochemical mechanism that controls the proteinogenic amino acid and ribonucleotide assembly from prebiotic mixtures suggests that these essential classes of metabolite had a unified chemical origin.
- Islam, Saidul,Bu?ar, Dejan-Kre?imir,Powner, Matthew W.
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p. 584 - 589
(2017/05/31)
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- Glucose promoted facile reduction of azides to amines under aqueous alkaline conditions
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A quick and efficient method for the reduction of azides to amines in water using d-glucose and KOH as green reagents is reported. The protocol is simple, inexpensive, scalable, and can be applied to different aromatic, heteroaromatic and sulphonyl azides. A high level of chemoselectivity is observed for azide reduction in the presence of other reducible functionalities like cyano, nitro, ether, ketone, amide and acid. The reaction gets completed in a short time (5-20 minutes), and furnishes the amines in high yield (85-99%). Unlike conventional hydrogenations, this reduction protocol does not require any metal catalyst, elaborate experimental setup or use of high-pressure equipment.
- Chandna, Nisha,Kaur, Fatehjeet,Kumar, Shobhna,Jain, Nidhi
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supporting information
p. 4268 - 4271
(2017/09/29)
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- Nanostarch: a novel and green catalyst for synthesis of 2-aminothiazoles
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Abstract: In this work, starch nanoparticles as a green and cheap catalyst were obtained based on the precipitation of amorphous starch in ethanol. It was found that starch nanoparticles are efficient catalyst for the synthesis of 2-aminothiazoles using methylcarbonyl compounds and thiourea as precursors. The use of green and biodegradable nanostarch makes this present methodology quite simple, shorter reaction times and milder conditions, and more convenient and economically viable compared to catalyzed methods reported in the literature. Graphical abstract: [Figure not available: see fulltext.]
- Safari, Javad,Sadeghi, Masoud
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p. 745 - 749
(2017/03/17)
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- Synthesis of thiazole linked indolyl-3-glyoxylamide derivatives as tubulin polymerization inhibitors
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A series of thiazole linked indolyl-3-glyoxylamide derivatives were synthesized and evaluated for their in vitro cytotoxic activity against DU145 (prostate), PC-3 (prostate), A549 (lung) and HCT-15 (colon) cancer cell lines by employing the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Among all the synthesized compounds, compound 13d displayed cytotoxicity of IC50 = 93 nM towards DU145 cancer cell line. The most active compound 13d was also tested on RWPE-1 cells and was found to be safe compared to the DU145 cells. The target compounds were also evaluated for their inhibition activity of tubulin polymerization. Further, the treatment of compound 13d on DU145 cells led to the inhibition of cell migration ability. The detailed studies such as acridine orange/ethidium Bromide (AO/EB), DAPI, annexin V-FITC/propidium iodide staining assay suggested that the compound 13d induced apoptosis in DU145 cells. The influence of the cytotoxic compound 13d on the cell cycle distribution was assessed on the DU145 cell line, exhibiting a cell cycle arrest at the G2/M phase. Moreover, the treatment with compound 13d caused collapse of mitochondrial membrane potential and elevated intracellular ROS levels in DU145 cells. The results from molecular modelling studies revealed that these compounds bind at the colchicine binding site of the tubulin. Thus, this new molecular scaffold could be a new lead for the development of anticancer agents that target tubulin.
- Guggilapu, Sravanthi Devi,Guntuku, Lalita,Reddy, T. Srinivasa,Nagarsenkar, Atulya,Sigalapalli, Dilep Kumar,Naidu,Bhargava, Suresh K.,Bathini, Nagendra Babu
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- Synthetic method for 2-acetyl thiazole
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The invention relates to a synthetic method for 2-acetyl thiazole. The synthetic method comprises the following steps: firstly, preparation of 2-amino thiazole is carried out, namely, toluene, thiourea and chloroacetaldehyde are mixed, a reaction is carried out with stirring at a constant temperature, and 2-amino thiazole is prepared; secondly, preparation of 2-bromo thiazole is carried out, namely, 2-amino thiazole is dissolved in sulfuric acid, cooling is carried out, a sodium nitrite aqueous solution is added drop by drop slowly at a controlled temperature after concentrated nitric acid is added drop by drop, stirring is carried out continuously, a reaction is carried out, the solution after the reaction is added in a mixed solution of sodium bromide and copper sulphate, a bromination reaction is carried out, and 2-bromo thiazole is prepared; thirdly, preparation of 2-acetyl thiazole is carried out, namely, 2-bromo thiazole is added in a butyllithium solution, stirring is carried out, then ethyl acetate is added, a reaction is carried out, and 2-acetyl thiazole is prepared. The acetylation step of 2-bromo thiazole is improved, the reaction raw material ratio and the reaction temperature are optimized, the high yield of the reaction is achieved, safe and reliable operation of the experiment is ensured effectively, and unexpected technical effects are achieved.
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Paragraph 0060; 0061
(2016/10/08)
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- Synthesis of 2-aminothiazoles from methylcarbonyl compounds using a Fe3O4 nanoparticle-: N -halo reagent catalytic system
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An efficient protocol is developed for the synthesis of 2-aminothiazoles from unfunctionalized methylcarbonyl compounds using Fe3O4 nanoparticle-N-halo reagent catalytic systems. 1,3-dichloro-5,5-dimethylhydantoin (DCDMH), N-bromosuccinimide (NBS) and N-iodosuccinimide (NIS) as N-halo reagents were explored and the best results were obtained for DCDMH. Fe3O4 nanoparticle-DCDMH as an active, reusable, excellent, highly stable magnetic catalyst was used in this process. Advantages of this efficient method include greener and cleaner conditions, shorter reaction time, excellent yield of products, easy separation using a simple external magnetic field, low cost and operational simplicity.
- Sadeghi, Masoud,Safari, Javad,Zarnegar, Zohre
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p. 64749 - 64755
(2016/07/21)
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- Montmorillonite K10: an effective catalyst for synthesis of 2-aminothiazoles
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An efficient one-pot synthesis of 2-aminothiazoles from methylcarbonyl and thiourea has been developed using montmorillonite-K10 as a catalyst at 80?°C in DMSO medium. A plausible mechanism is proposed in which α-iodomethylcarbonyls are formed via methylcarbonyls as raw material using iodine as iodination reagent.
- Safari, Javad,Sadeghi, Masoud
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p. 8175 - 8183
(2016/11/25)
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- Magnetic carbon nanotube-supported imidazolium cation-based ionic liquid as a highly stable nanocatalyst for the synthesis of 2-aminothiazoles
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Magnetic carbon nanotube-supported imidazolium ionic liquid (CNT-Fe3O4-IL) was synthesized and investigated using various characterization techniques, including Fourier transform infrared and Raman spectroscopies, X-ray diffraction, vibrating sample magnetometry, scanning and transmission electron microscopies, and thermogravimetric and differential thermal analyses. In order to synthesize the CNT-Fe3O4-IL nanocomposites, Fe3O4-decorated multi-walled CNTs were modified with 1-methyl-3-(3-trimethoxysilylpropyl)-1H-imidazol-3-ium chloride. This catalytic system was found to be a highly stable, active, reusable and solid-phase catalyst for the synthesis of 2-aminothiazoles via the one-pot reaction of ketone, thiourea and N-bromosuccinimide under mild conditions. Immobilized magnetic ionic liquid catalysis combines the advantages of ionic liquid media with magnetic solid support nanomaterials which enables the application of nanotechnology and green chemistry in chemical processes. Copyright
- Zarnegar, Zohre,Safari, Javad
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p. 1043 - 1049
(2016/11/23)
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- Nanochitosan: A biopolymer catalytic system for the synthesis of 2-aminothiazoles
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A convenient and efficient method is described for the synthesis of 2-aminothiazoles by one-pot reaction of ketone and thiourea using chitosan nanoparticles under mild condition. Nanochitosan was used as a biodegradable and green catalyst for this reaction in satisfactory yields. The attractive advantages of the present process include easy isolation of products, milder and cleaner conditions, higher purity and yields and easier work-up procedure.
- Safari, Javad,Abedi-Jazini, Zahra,Zarnegar, Zohre,Sadeghi, Masoud
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p. 108 - 112
(2016/02/05)
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- Chemoselective N-deacetylation under mild conditions
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A mild and efficient chemoselective N-deacetylation using the Schwartz reagent at room temperature in rapid time is described. The mild and neutral conditions enable orthogonal N-deacetylation in the presence of some of the common protecting groups (viz. Boc, Fmoc, Cbz, Ts). The deprotection conditions did not induce any epimerization at the chiral amino centre.
- Sultane, Prakash R.,Mete, Trimbak B.,Bhat, Ramakrishna G.
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supporting information
p. 261 - 264
(2014/01/06)
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- Polymethylhydrosiloxane derived palladium nanoparticles for chemo- and regioselective hydrogenation of aliphatic and aromatic nitro compounds in water
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Chemo- and regioselective hydrogenation of a wide range of aliphatic, unsaturated, aromatic and heteroaromatic nitro compounds into their corresponding amines has been achieved with highly efficient polysiloxane-stabilised "Pd" nanoparticles on NAP-magnesium oxide supports using an environmentally friendly hydrogenating agent, polymethylhydrosiloxane [PMHS] in water. Highly stable and active Pd nanoparticles were prepared by the reduction of NAP-Mg-PdCl4 with PMHS, which serves as a reducing agent as well as a capping agent. The well-dispersed palladium nanoparticles on NAP-MgO catalysts also exhibit excellent regioselectivity in the hydrogenation of dinitrobenzenes to the corresponding nitroanilines. The catalyst has high durability against sintering during the hydrogenation reaction and can be reused with no loss in its activity. This journal is the Partner Organisations 2014.
- Damodara, Dandu,Arundhathi, Racha,Ramesh Babu, T. Venkata,Legan, Margaret K.,Kumpaty, Hephzibah J.,Likhar, Pravin R.
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p. 22567 - 22574
(2014/06/23)
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- Discovery of novel N-(5-(arylcarbonyl)thiazol-2-yl)amides and N-(5-(arylcarbonyl)thiophen-2-yl)amides as potent RORγt inhibitors
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Novel series of N-(5-(arylcarbonyl)thiazol-2-yl)amides and N-(5-(arylcarbonyl)thiophen-2-yl)amides were discovered as potent retinoic acid receptor-related orphan receptor-gamma-t (RORγt) inhibitors. SAR studies of the RORγt HTS hit 6a led to identification of thiazole ketone amide 8h and thiophene ketone amide 9g with high binding affinity and inhibitory activity of Th17 cell differentiation. Compound 8h showed in vivo efficacy in both mouse experimental autoimmune encephalomyelitis (EAE) and collagen induced arthritis (CIA) models via oral administration.
- Wang, Yonghui,Cai, Wei,Zhang, Guifeng,Yang, Ting,Liu, Qian,Cheng, Yaobang,Zhou, Ling,Ma, Yingli,Cheng, Ziqiang,Lu, Sijie,Zhao, Yong-Gang,Zhang, Wei,Xiang, Zhijun,Wang, Shuai,Yang, Liuqing,Wu, Qianqian,Orband-Miller, Lisa A.,Xu, Yan,Zhang, Jing,Gao, Ruina,Huxdorf, Melanie,Xiang, Jia-Ning,Zhong, Zhong,Elliott, John D.,Leung, Stewart,Lin, Xichen
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supporting information
p. 692 - 702
(2014/01/23)
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- Microwave-assisted protection of primary amines as 2,5-dimethylpyrroles and their orthogonal deprotection
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Primary amines can be readily doubly protected as N-substituted 2,5-dimethylpyrroles. Although this protecting group is stable toward strong bases and nucleophiles, long reaction times are required for both the protection and deprotection steps, generally resulting in low deprotection yields. By employing microwave irradiation, protection and deprotection reaction times are dramatically reduced. Furthermore, deprotection with dilute hydrochloric acid in ethanol increases reaction yields. Diverse deprotection conditions have been developed in conjunction with microwave irradiation, so that protection as an N-substituted 2,5-dimethylpyrrole can be orthogonal to other standard amine protecting groups, such as tert-butyloxycarbonyl (Boc), carbobenzyloxy (Cbz), and 9-fluorenylmethyloxycarbonyl (Fmoc).
- Walia, Amit,Kang, Soosung,Silverman, Richard B
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p. 10931 - 10937
(2013/11/19)
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- Reduction of organic azides to amines using reusable Fe3O 4 nanoparticles in aqueous medium
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Aromatic, heteroaromatic and sulfonyl azides were conveniently reduced to the corresponding amines in excellent yields using hydrazine hydrate in the presence of iron oxide nanoparticles. The Fe3O4-MNPs could be easily separated by an external magnet, and recycled ten times without significant loss of the catalytic efficiency. The Royal Society of Chemistry 2013.
- Pagoti, Sreenivasarao,Surana, Subham,Chauhan, Ajay,Parasar, Bibudha,Dash, Jyotirmayee
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p. 584 - 588
(2013/03/28)
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- Ligandless copper-catalyzed coupling of heteroaryl bromides with gaseous ammonia
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A range of different N- and S-containing heterocyclic bromides can be efficiently coupled with gaseous ammonia in the presence of copper(II) acetylacetonate [Cu(acac)2] as catalyst and in the absence of additional ligands. Unstable aminothiophenes and aminobenzothiophenes can be further reacted in situ to afford functionalized derivatives. Copyright
- Fantasia, Serena,Windisch, Johannes,Scalone, Michelangelo
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supporting information
p. 627 - 631
(2013/04/11)
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- Multicomponent assembly of proposed DNA precursors in water
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We propose a novel pathway for the prebiotic synthesis of 2′-deoxynucleotides. Consideration of the constitutional chemical relationships between glycolaldehyde and β-mercapto-acetaldehyde, and the corresponding proteinogenic amino acids, serine and cysteine, led us to explore the consequences of the corresponding sulfur substitution for our previously proposed pathways leading to the canonical ribonucleotides. We demonstrate that just as 2-aminooxazole-an important prebiotic ribonucleotide precursor-is readily formed from glycolaldehyde and cyanamide, so is 2-aminothiazole formed from β-mercapto-acetaldehyde and cyanamide in water at neutral pH. Indeed, both the oxazole and the thiazole can be formed together in a one-pot reaction, and can be co-purified by crystallization or sublimation. We then show that 2-aminothiazole can take part in a 3-component carbon-carbon bond-forming reaction in water that leads to the diastereoselective synthesis of masked 2′-thiosugars regiospecifically tethered to purine precursors, which would lead to 2′-deoxynucleotides upon desulfurization. The possibility of an abiotic route to the 2′-deoxynucleotides provides a new perspective on the evolutionary origins of DNA. We also show that 2-aminothiazole is able to sequester, through reversible aminal formation, the important nucleotide precursors glycolaldehyde and glyceraldehyde in a stable, crystalline form.
- Powner, Matthew W.,Zheng, Shao-Liang,Szostak, Jack W.
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experimental part
p. 13889 - 13895
(2012/10/08)
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- Synthesis of 2-azido-1,3-thiazoles as 1,2,3-triazole precursors
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By diazotization of 2-aminothiazoles and reaction with sodium azide, the derivatives of 2-azidothiazole were synthesized. Conditions of diazotization were selected according to the nature of a substituent in thiazoles. 2-Azidothiazole derivatives were studied in the base-catalysed condensation reactions with activated methylenic compounds to yield new 1-(1,3-thiazol-2-yl)- 1H-1,2,3-triazole-4-carboxylic acids.
- Pokhodylo, Nazariy T.,Savka, Roman D.,Pidlypnyi, Nazar I.,Matiychuk, Vasyl S.,Obushak, Mykola D.
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scheme or table
p. 391 - 399
(2010/03/30)
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- Reactivity of neutral nitrogen donors in square-planar d8 metal complexes: The system chloro(2,2′:6′,2″-terpyridine)platinum(II) cation with five-membered N-donor heterocycles in methanol
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The kinetics of the forward and reverse steps of the reaction [Pt(terpy)Cl]+ + nu ? [Pt(terpy)(nu)]2+ + Cl- (terpy = 2,2′:6′,2″-terpyridine, nu = one of a number of thiazoles, oxazole, isoxazole, imidazole, pyrazole and 3,5-dimethylpyrazole, covering a wide range of basicities) have been studied in methanol at 25 °C. Both forward and reverse reactions obey the usual two-term rate law observed in square-planar substitution. The second-order rate constants for the forward reactions, k2f, show a slight dependence upon the basicity of the entering nu, while the steric hindrance due to the presence of one methyl group in the α position to the nitrogen markedly decreases the reactivity. The second-order rate constants for the reverse reactions, k2r, are very sensitive to the nature of the leaving group and a plot of log k2r against the pKa of the conjugate acids of the unhindered five-membered N-donors is linear with a slope of -0.51. The results are compared with data from the literature regarding a series of pyridines reacting with the [Pt(terpy)Cl]+ cation under the same experimental conditions. Both in the forward and in the reverse reaction, the reactivity depends not only upon the ligand basicity but also upon the nature of the nucleophile in the order: (thiazoles, oxazole, isoxazole, imidazole, pyrazoles) > pyridines for the entry of N-donors and on the contrary for the displacement by Cl-. Steric retardation, due to the presence of a methyl group in the α position to the nitrogen, is remarkably lower for five-membered N-donors if compared to pyridines both in the forward and in the reverse reaction.
- Pitteri, Bruno,Bortoluzzi, Marco
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p. 2698 - 2704
(2008/10/09)
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- Mechanism of hydrolysis of substituted N-thiazolylcarbamate esters in OH- solutions
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Substituted secondary N-thiazolylcarbamate esters and some tertiary N-methyl, N-thiazolyl carbamate esters have been synthesised and the mechanism of the OH- catalysed hydrolyses investigated. These proved to be E1cB and BAc2 respectively, and this behaviour was compared with that of other carbamates.
- Araujo, M. Eduarda M.,Norberto, Fatima,Pamplona, Teresa,Iley, Jim
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p. 664 - 667
(2007/10/03)
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- Process for making substituted thiazolyl-amino pyrimidinyl
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The present invention relates to a process for preparing substituted thiazolyl-amino pyrimidinyl piperazines, which are capable of inhibiting, modulating and/or regulating signal transduction of both receptor-type and non-receptor type tyrosine kinases.
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Page/Page column 7; 8
(2010/11/30)
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- NOVEL FLORFENICOL-TYPE ANTIBIOTICS
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The present invention relates to novel florfenicol compounds having the chemical structure: wherein the compounds are useful for the treatment and/or prevention of bacterial infections in a broad range of patients such as, without limitation, birds, fish, shellfish and mammals
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- Thiazole, imidazole and oxazole compounds and treatments of disorders associated with protein aging
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Provided are, among other things, compounds of formula I or IA, . Also provided are methods of treatment with such compounds.
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- 2-aminopyridine derivatives and combinatorial libraries thereof
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The present invention relates to novel 2-aminopyridine derivative compounds of the following formula: wherein R1to R5have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing 2-aminopyridine derivative compounds.
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- Inhibitory effect of 2-aminothiazole derivatives in oxidation reactions
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The kinetics and mechanism of inhibitory effect of 2-aminothiazole derivatives in the radical-initiated oxidation of cumene were studied.
- Karpov,Pekarevskii,Potekhin
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p. 1484 - 1486
(2007/10/03)
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- Biocidal and anticorrosive effect of 2-aminothiazole derivatives used as additives to jet fuels
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The effect of 2-aminothiazole derivatives on the biological resistance and corrosion activity of jet fuels was studied under conditions of water condensation.
- Karpov,Nazarenko,Pekarevskii,Potekhin
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p. 998 - 1001
(2007/10/03)
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- Amination of aryl halides using copper catalysis
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Bromopyridine 4 was converted into aminopyridine 5 under Cu2O catalysis with an ethylene glycol solution of ammonia in excellent yield (90%). The amination reaction features low (0.5 mol%) catalyst loading, mild reaction temperature (80°C) and low reaction pressure (50 psi). This protocol is further studied in the amination of a variety of aryl halides.
- Lang, Fengrui,Zewge, Daniel,Houpis, Ioannis N.,Volante
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p. 3251 - 3254
(2007/10/03)
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- Thiazole derivatives
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Compounds of the formula: as well as pharmaceutically usable salts and esters thereof, wherein R1, R2 and R3 have the significance ascribed herein, inhibit binding of adhesive proteins to the surface of different types of cell and accordingly influence cell-cell and cell-matrix interactions. These compounds can be used in the form of pharmaceutical preparations for the control or prevention of neoplasms, tumor metastasing, tumor growth, osteoporosis, Paget's disease, diabetic retinopathy, macular degeneration, restenosis following vascular intervention, psoriasis, arthritis, fibrosis, kidney failure, as well as infection caused by viruses, bacteria or fungi.
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- Substituted 4-phenylaminothiazoles, their process of preparation and the pharmaceutical compositions containing them
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A compound, as well as its stereoisomers and addition salts, possssing antagonist activity with respect to corticotropin releasing hormone (CRF) has the formula: STR1 in which R1, and R21 which are identical or different, are independently selected from a halogen atom; a (C1 -C5)hydroxyalkyl radical; a (C1 -C5)alkyl; a (C7 -C10)aralkyl; a (C1 -C5)alkoxy; a trifluoromethyl; a nitro; a nitrile; an --SR group in which R is selected from hydrogen, a (C1 -C5)alkyl radical and a (C7 -C10)aralkyl radical; an --S--CO--R group in which R is selected from a (C1 -C5)alkyl radical and an aralkyl radical in which the aryl part is (C6 -C8) and the alkyl part is (C1 -C4); a --COOR' group in which R' is selected from hydrogen and a (C1 -C5)alkyl; a --CONR--R'R" group with R' and R" as defined above for R'; an --NR'R" group with R' and R" as defined above for R'; a --CONRaRb or --NRaRb group in which Ra and Rb constitute, with the nitrogen atom to which they are bonded, a 5- to 7-membered heterocycle; and an --NHCO--NR'R" group with R' and R" as defined above for R'; R3 represents hydrogen or is as defined above for R1 and R2 ; R4 is selected from a hydrogen atom; a (C1 -C5)alkyl; a halogen, a hydroxymethyl group; and a formyl group; R5 is selected from a (C1 -C5)alkyl; a (C3 -C7)cycloalkyl group; a cycloalkylalkyl group in which the cycloalkyl part is (C3 -C7) and the alkyl part is (C1 -C5); and alkenyl containing 5 to 6 carbon atoms; n represents zero or one; R6 is selected from a (C1 -C5)alkyl; an alkoxyalkyl in which the alkyl parts are (C1 -C5); a (C3 -C7)cycloalkyl; a cycloalkylalkyl group in which the cycloalkyl part is (C3 -C7) and the alkyl part is (C1 -C5); a cycloalkyloxyalkyl radical in which the cycloalkyl is (C3 -C7) and the alkyl part is (C1 -C4); a hydroxyalkyloxyalkyl radical in which the alkyls are (C2 -C10); and an alkoxyalkyloxyalkyl radical in which the alkyls are (C3 -C12); Z represents an optionally substituted bi- or tricyclic aromatic or heteroaromatic group.
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- Synthesis of [1,3,4]thiadiazolo[3,2-a]pyrimidines in the presence of formic acid
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Formic acid-phosphorus pentoxide was effective for the preparation of 5,7-dimethyl[1,3,4]thiadiazolo- and -[1,3]thiazolo[3,2-a]pyrimidin-4-ium salts. Further, the pyrimidine ring transformation and the isocyanation of 5imino-6H-[1,3,4]thiadiazolo- and -[1,3]thiazolo[3,2-a]pyrimidin-7-ones were carried out in the presence of formic acid and triethyl orthoformate, respectively.
- Takenaka, Keiko,Tsuji, Tadakazu
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p. 1367 - 1370
(2007/10/03)
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- CONDENSED THIADIAZOLE DERIVATIVE, METHOD OF ITS PRODUCTION, AND USE THEREOF
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(1) a compound represented by the following formula (I): STR1 wherein R represents a hydrocarbon group or heterocyclic group which may be substituted; the ring A represents a pyridine ring having a substituent or a thiazole ring which may be substituted; or a pharmaceutically acceptable salt thereof, and a method of its production, and(2) an endothelin receptor antagonist, an cathepsin B inhibitor or a bone resorption suppressor having as an active ingredient a compound represented by the following formula (I') : STR2 wherein R has the same definition as in term (1); the ring A' represents a pyridine ring or thiazole ring which may be substituted; or a pharmaceutically acceptable salt thereof.
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- One-pot Preparation of 2-Chloromethyldioxolanes and 2-Aminothiazoles from Chloromethyltrioxanes
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Thermal degradation of chloromethyltrioxanes in the presence of catalytic amount of montmorillonite clay generated α-chloroaldehydes with high purity, which were treated in situ with ethylene glycol or thiourea to afford 2-chloromethyldioxolanes and 2-aminothiazoles, respectively.The clay catalysts used were removed by filtration.
- Wakasugi, Takashi,Miyakawa, Tadashi,Suzuki, Fukuichi,Itsuno, Shinichi,Ito, Koichi
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p. 2039 - 2042
(2007/10/02)
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- Heterocyclic substituted 2-acylamino-5-thiazoles, their preparation and pharmaceutical compositions containing them
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A 2-Acylaminothiazole of formula: STR1 in which R1 is H, an alkyl or a substituted alkyl; RIV is a cycloalkyl, an aromatic group such as phenyl or a heterocyclic group which are unsubstituted or substituted; RV is a substituted alkyl, a substituted carboxy such as an ester or an amide; or RIV and RV together represent a phenoxyalkylene group which may be substituted on the phenyl; and Z is a heterocyclic e.g. indolyl group; or a salt of compound (I).
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- Synthesis of 2-(aminoacetylamino)thiazole derivatives and comparison of their local anaesthetic activity by the method of action potential
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Some numbers of the family of 2-(aminoacetylamino)thiazoles were synthesized. The structure of these compounds was identified both by elemental as well as by spectroscopic analysis (UV, IR, H-NMR, MS). The possible local anaesthetic action of these compounds was also tested using the sciatic nerve of the frog. None of the tested compounds were found to have local anaesthetic action on in vitro preparations as lidocaine, but one of the compounds showed a similar anaesthetic action to procaine.
- Geronikaki,Theophilidis
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p. 709 - 716
(2007/10/02)
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- Process of producing 2-aminothiazole
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A process of obtaining high-pure 2-aminothiazole at a high yield by reacting monochloroacetaldehyde obtained by depolymerizing a monochloroacetaldehyde trimer and thiourea in an organic solvent.
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- Studies on Decarboxylation Reactions. Part 7. Kinetic Study of the Decarboxylation of 2-Amino- and 2-Phenylamino-thiazole-5-carboxylic Acids
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The rate constants of the decarboxylation reaction of 2-amino- and 2-phenylamino-thiazole-5-carboxylic acid (3a-b), and, for comparison, of 5-phenylamino-1,3,4-thiadiazole-2-carboxylic acid (2b) have been measured in water over a range of proton activities.The results obtained suggest: (i) compound 2b decarboxylates, in the whole range of proton activity studied, through a unimolecular decarboxyprotonation mechanism characteristic of 1,3,4-oxa- and 1,3,4-thiadiazole derivatives; (ii) in contrast, 3a-b decarboxylate via either a unimolecular decarboxyprotonation or a bimolecular protiodecarboxylation mechanism as a function of proton activity.
- Noto, Renato,Ciofalo, Maurizio,Buccheri, Francesco,Werber, Guiseppe,Spinelli, Domenico
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p. 349 - 352
(2007/10/02)
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- Oxidation hair-dyeing preparations
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Oxidation hair-dyeing preparations which contain as couplers N-(2-4dihydroxbenzylidene)-amino compounds corresponding to the following formula STR1 in which A is a group corresponding to one of the following formulae STR2 or salts thereof and the developers normally present in oxidation hair dyes. p-Phenylenediamine and derivatives thereof are particularly suitable as developers. Yellow to olive-brown colors of high fastness are obtained.
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- Kinetics of Hydrolysis of Schiff Bases Derived from 2-Aminothiazole and 2-Aminothiadiazole
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Kinetics of hydrolysis of schiff bases, viz, benzylidene-2-aminothiazole and 2-aminothiadiazole (I, II) and o-hydroxybenzylidenes-2-amino-5-substituted-thiadiazole (III) have been studied in 30percent (w/w) ethanol-water mixture.The results indicate that the rate-determining step is changed from OH(-) attack on the free schiff base in alkaline media to attack by water on the protonated schiff base in neutral or weakly acidic media.The results of study of solvent effects on base hydrolysis rates suggest that specific solute-solvent interactions, viz. dispersion forces and intermolecular H-bonding play important role.
- Mahmoud, M. R.,El-Nady, A. M.,Hamed, M. M. A.
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p. 596 - 599
(2007/10/02)
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- Influence of Substituents on the Synthesis of Thiazolidinones
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The influence of substituents (subunits) in the synthesis of thiazolidinones by the reaction of unsymmetrical thioureas with monochloroacetic acid in ethanol has been rationalised by the characterisation of the hydrolysis products of the resulting thiazolidinones.The formation of thiol from thiourea, which is the key intermediate in thiazolidinone synthesis, invariably involves the -NH- group adjacent to more electron withdrawing subunits.
- Sabu, M.,Garnaik, B. K.,Behera, Rajani K.
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p. 779 - 781
(2007/10/02)
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- CONDENSATION REACTIONS BETWEEN AROMATIC ALDEHYDES AND SOME HETEROCYCLIC AROMATIC AMINES
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1,1-Diamino derivatives are obtained by means of reactions between 2-aminothiazole and aromatic aldehydes carried out in methanol (and in dimethyl sulphoxide).The reaction of amine with the C=N of imine occurs without catalyst and is an easier process than its addition to C=O.This behaviour is also displayed by a number of aromatic heterocycles and homocyclic amines and may be explained by considering the activating effect of the electron-withdrawing group present in the imine moiety.
- Forlani, Luciano,Sintoni, Marina,Todesco, Paolo E.
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p. 229 - 232
(2007/10/02)
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- Hydrolysis of Imines. 4. Micellar Effects upon the Spontaneous Acid, Base, and Copper(II) Ion Induced Hydrolysis of N-Salicylidene-2-aminothiazole and N-Salicylidene-2-aminopyridine
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The rate of hydrolysis of the title imines in alkaline medium was strongly retarded by the cationic surfactant cetyltrimethylammonium bromide (CTAB) even though both reactants (i.e., the phenoxide forms of the imines and OH-) might be bound to the micellar pseudophase.Anionic surfactant sodium dodecyl sulfate (SDS) did not affect the hydrolysis rate at pH>12.In mild alkaline medium (pH 9.2) both surfactants retarded the hydrolysis reaction of the imines, the effect being much stronger in the case of CTAB.Inhibition was attributed to selective partitioning of the phenol form of the imines into the micellar pseudophase of SDS, while both the phenol and phenoxide forms of the imines were found to be adsorbed in the micellar pseudophase of CTAB, where these undergo hydrolysis much slower than in the aqueous pseudophase.In the range pH 5.08-7.06, small acceleration in the rate of hydrolysis of the thiazole imine by SDS was observed.There was virtually no kinetic effect of SDS on the copper(II)-induced hydrolysis of the thiazole imine.Strikingly the copper(II)-N-salicylidene-2-aminopyridine chelate (CuL+) was found to undergo faster acid-catalyzed hydrolysis of the aldimine linkage in the micellar pseudophase of SDS than in the aqueous phase.
- Dash, Anadi C.,Dash, Bhasker,Panda, Debraj
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p. 2905 - 2910
(2007/10/02)
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- Iminoisoindolinone metal complex
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Iminoisoindolinone metal complexes of formula STR1 wherein A represents a 5- or 6-membered heterocyclic radical which contains at least one further heteroatom and can be fused or doubled with benzene nuclei, M represents a divalent metal atom excluding the alkaline earth metals, X represents a hydrogen atom, Y represents a halogen atom, Z represents a nitro group, an alkoxycarbonyl group of 2 to 6 carbon atoms or a group of formula RY2 --, wherein R represents a hydrogen atom, an alkyl group of 1 to 6 carbon atoms which is substituted by an aryl radical or is unsubstituted, a cycloalkyl group of 5 to 6 carbon atoms, or represents an aryl group, and Y2 represents an oxygen or a sulphur atom, m and n are 0 to 4, p is 0 to 2, and the sum of m+n+p must be 4, which are useful for pigmenting high molecular organic material.
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