Synthesis of thiazole derivatives XXIII. 2-Methylbenzimidazoles with thiazole,benzothiazole, and quinoline groups as substituents

Derivatives of 1-phenyl-2-methylbenzimidazole, with nitrogen heterocycle groups thiazole, 4-substituted thiazole, benzothiazole, and quinoline, at position 5, are synthesized. The ethiodides of the new bases are used to prepare cyanine dyes: imidadimethinemero-, imidacarbo-, and, imidadicarbocyanines.     

Synthesis of oligonucleotides containing thiazole and thiazole N-oxide nucleobases

[reaction: see text] The thiazole C-nucleoside analogue was synthesized by the Hantzsch cyclization method to form the thiazole ring and was then converted to the thiazole N-oxide C-nucleoside analogue by peracid oxidation of the heterocycle nitrogen. Incorporation of the thiazole and thiazole N-oxide phosphoramidites into DNA was successful though significant deoxygenation of the N-oxide occurred during DNA assembly. The mechanism proposed for the reduction of the thiazole N-oxide to thiazole involves the formation of an N-oxide phosphite ester.     

Fluorescent properties of oligonucleotide-conjugated thiazole orange probes

The fluorescence properties of thiazole orange, linked via a (1) hydrophobic alkyl or a (2) hydrophilic ethylene glycol chain to the central internucleotidic phosphate group of a pentadeca-2'-deoxyriboadenylate (dA15), are evaluated. Linkage at the phosphate group yields two stereoisomers, S-isomer of the phosphorus chiral center (Sp) and R-isomer of the phosphorus chiral center (Rp); these are studied separately. The character of the linkage chain and the chirality of the internucleotidic phosphate linkage site influence the fluorescent properties of these thiazole orange-oligonucleotide conjugates (TO-probes). Quantum yields of fluorescence (phifl) of between 0.04 and 0.07 were determined for the single-stranded conjugates. The fluorescence yield increased by up to five times upon hybridization with the complementary sequence (d5'[CACT15CAC3']); (phifl values of between 0.06-0.35 were determined for the double-stranded conjugates. The phifl value (0.17) of thiazole orange, 1-(N,N'-trimethylaminopropyl)-4-[3-methyl-2,3-dihydro-(benzo-1,3-thiazole)-2-methylidene]-quinolinium iodide (TO-Pro 1) in the presence of the oligonucleotide duplex (TO-Pro 1: dA15.d5'[CACT15CAC3'] (1:1)) is much less than that for some of the hybrids of the conjugates. Our studies, using steady-state and time-resolved fluorescence experiments, show that a number of discrete fluorescent association species between the thiazole orange and the helix are formed. Time-resolved studies on the four double-stranded TO-probes revealed that the fluorescent oligonucleotide-thiazole orange complexes are common, only the distribution of the species varies with the character of the chain and the chirality at the internucleotidic phosphate site. Those TO-probes in which the isomeric structure of the phosphate-chain linkage is Rp, and therefore such that the fluorophore is directed toward the minor groove, have higher phifl values than the Sp isomer. Of the systems studied, thiazole orange linked by an alkyl chain to the internucleotidic phosphate (Rp isomer) has the highest phifl and the greatest fraction of the longest-lived fluorescent thiazole orange species (in the hybrid form).     

Synthesis of thiazole aminophosphine oxides, aminophosphonic and aminophosphinic acids and Cu(II) binding abilities of thiazole aminophosphonic acids

A series of new aminophosphine oxides, aminophosphonic and aminophosphinic acids derived from thiazole was synthesized by addition of phosphine oxides or silylated phosphorus esters to the corresponding thiazole aldimines. The thiazole aldimines were obtained from 2-thiazole aldehyde and primary amines by a standard procedure. The corresponding phosphine oxides were obtained by alkylation of diethyl phosphite or ethyl phenylphosphinate with the appropriate Grignard reagents. The silylated phosphorus esters were prepared from trimethyl phosphite and from methyl- or phenylphosphinic ethyl ester by treatment with bromotrimethylsilane. The coordination ability towards Cu(II) ions are described for two obtained aminophosphonate ligands.     

Muscarine, imidazole, oxazole, and thiazole alkaloids

The occurrence, structure determination, biological activities, as well as total syntheses of muscarine, imidazole, oxazole and thiazole alkaloids have been reviewed. The literature covers from the middle of 2001 to the end of 2002, and 149 references are cited.     

Practical synthesis of a highly functionalized thiazole ketone

Compound 1 is a uniquely substituted ketone prepared via addition of a thiazole anion to an aromatic nitrile in good overall yield. An exploration into the generality of the addition of thiazole anions to nitriles allowed us to make a variety of thiazole ketones in good to excellent yields. The non-odorous thiolate-mediated demethylation reaction used in the synthesis of 1 is also presented.     

Synthesis of 2-methylphenanthro[2, 1-d]thiazole

2-Methylphenanthro[2, 1-d]thiazole has been synthesized by the oxidative cyclization of 2-thioacetylaminophenanthrene.     

Residue and dissipation of zinc thiazole in tobacco field ecosystem

A high-performance liquid chromatography with ultraviolet (HPLC-UV) detection method after derivatisation was developed for the first time for the novel fungicide zinc thiazole residue in tobacco samples. Field trials in two different locations were conducted to investigate the dissipation and residue of zinc thiazole in tobacco leaves and soil. The average recoveries of zinc thiazole were in the range of 82.5%–93.9% with relative standard deviations (RSDs) of 1.2%–9.1%. The zinc thiazole showed a rapid dissipation rate in fresh tobacco leaves with the half-lives of 1.1–1.6 days. The terminal residues of zinc thiazole in cured tobacco leaves and soil were 2.8–28.0 mg kg^?1and <0.05 mg kg^?1, respectively. The results could be used to establish the maximum residue limits (MRLs) and provide guidance for the scientific use of zinc thiazole in agriculture.     

Muscarine, imidazole, oxazole, and thiazole alkaloids

A great number of structurally diverse natural products containing five-membered heterocyclic subunits, such as imidazole, oxazole, thiazole, and their saturated congeners, are abundant in nature. These naturally occurring metabolites often exhibit extensive and pharmacologically important biological activities. The latest progress in the isolation, biological activities, chemical synthetic studies, and biosynthetic pathways on these natural products is summarized in this review.     

Polymethine dyes — Indolo[3,2-d]thiazole derivatives

New polymethine dyes with an indolo[3,2-d]thiazole residue are described, and their spectral properties are discussed. Replacement of the vinylene group in the naphtho[1,2-d]thiazole residue by an NH group leads to a considerably greater bathochromic shift of the absorption maximum of carbo- and merocyanines as compared with replacement by a sulfur atom. The basicity of the indolo[3,2-d]thiazole residue is higher than the basicity of the naphtho[1,2-d]-thiazole and thionaphtheno[3,2-d]thiazole residues.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1606–1610, December, 1972.     

The synthesis of unsubstituted phenanthro [2, 1-d] thiazole

Phenanthro [2, 1-d] thiazole was obtained by the oxidative ring-closure of 2-phenanthrylthiooxamic acid to the corresponding phenanthrothiazole-2-carboxylic acid, which was then decarboxylated.     

Muscarine, imidazole, oxazole and thiazole alkaloids

Novel and structurally diverse natural products containing imidazol-, oxazole-, or thiazole-unit(s) display a wide variety of biological activities. The isolation, biological activity and total synthesis of naturally occurring muscarine, imidazole, oxazole and thiazole alkaloids have been reviewed. The literature covers from January 2003 to June 2004.     

Synthesis and MRSA PK inhibitory activity of thiazole containing deoxytopsentin analogues

The public health care crisis caused by the emergence of drug resistant bacterial strains, e.g., methicillin resistant Staphylococcus aureus (MRSA) has underlined the urgent need to accelerate the discovery of new chemical entities active against antibiotic resistant bacteria. We report here the synthesis of a series thiazole containing deoxytopsentin analogues, which show moderate activity against a target MRSA pyruvate kinase enzyme: an evolutionary conserved hub protein critical for bacterial survival. A Hantzsch thiazole coupling between α-oxo-1H-indole-3-thioacetamides and 2-bromo-1-(1H-indol-3-yl)-ethanones provided facile access to the thiazole containing deoxytopsentin compounds.     

Selenonaphtheno[2,3-d]thiazole derivatives as polymethine dyes

New polymethine dyes — selenonaphtheno[2,3-d]thiazole derivatives — were synthesized. It is shown that all of the synthesized dyes which have a selenonaphtheno[2,3-d]thiazole residue are more deeply colored than the corresponding 6,7-benzobenzothiazole and thionaphtheno[2,3-d] thiazole derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 459–461, April, 1971.     

Cyclization of substituted 1, 4-diphenylthiosemicarbazides to thiazole derivatives

Heating together substituted 1, 4-diphenylthiosemicarbazides and-bromoacetophenone in ethanol gives new bases and quaternary salts of 2, 3, 4-substituted thiazole.     

A retrospect on antimicrobial potential of thiazole scaffold

Due to its appreciable diversity in biological actions, thiazole and its substituted components, a significant class of heterocyclic compounds has developed as an influential scaffold in the field of chemical sciences. The variability of thiazole core has been expressed through the effective instigation of its anticancer (Dasatinib, Tiazofurin), antiretroviral (Ritonavir, Brecanavir), antimicrobial (Sulfathiazole, Ravuconazole) and anti-inflammatory (Fenclozic acid, Meloxicam) derivatives. This reasonable diversity in the physiological reaction pattern led many scientists to refine and develop new structural alternatives with much more efficient pharmacological action. This review is crucial for previous studies and projects to survey the antimicrobial activity of thiazole and thiazole related compounds to the mid of 2019.     

Synthesis of monothiooxamides of the thiazole series

A convenient method for the synthesis of previously inaccessible monothiooxamides of the thiazole series was developed. The method is based on the reaction of pyridinium salts obtained from 2-(chloroacetylamino)thiazole and pyridine with a solution of elemental sulfur and amines prepared beforehand.     

噻唑类化合物应用研究新进展

噻唑环是一类重要的含氮硫杂原子的五元芳杂环,其特殊的结构使得噻唑类化合物在化学、药学、生物学和材料科学等诸多领域具有广阔的应用前景,显示出巨大的开发价值,受到广泛关注.本文结合作者的研究工作,参考国内外近五年文献,系统地综述了噻唑类化合物在医药、农药、材料、生物染色剂和超分子化学领域应用研究进展.     

Synthesis of sansalvamide A peptidomimetics: triazole, oxazole, thiazole, and pseudoproline containing compounds

Peptidomimetic-based macrocycles typically have improved pharmacokinetic properties over those observed with peptide analogs. Described are the syntheses of 13 peptidomimetic derivatives that are based on active Sansalvamide A structures, where these analogs incorporate heterocycles (triazoles, oxazoles, thiazoles, or pseudoprolines) along the macrocyclic backbone. The syntheses of these derivatives employ several approaches that can be applied to convert a macrocyclic peptide into its peptidomimetic counterpart. These approaches include peptide modifications to generate the alkyne and azide for click chemistry, a serine conversion into an oxazole, a Hantzsch reaction to generate the thiazole, and protected threonine to generate the pseudoproline derivatives. Furthermore, we show that two different peptidomimetic moieties, triazoles and thiazoles, can be incorporated into the macrocyclic backbone without reducing cytotoxicity: triazole and thiazole.     

Muscarine,imidazole, oxazole,thiazole, Amaryllidaceae and Sceletium alkaloids

A review with 136 references covers the literature from July 2000 to June 2001 on the isolation, bioactivities, and synthetic highlights of complex natural products including muscarine, imidazole, oxazole, thiazole, Amaryllidaceae and Sceletium alkaloids.