2-Thiazolyl pyridines

Thiazolyl pyridine, gas-liquid chromatography of, relative retention volume, 358... 

The 5-position is the preferred site for sulfonation (58. 392). This position is more reactive than any of the pyridine ring in. V-[pyridyl-(2)]-thiazolyl-(2)-amine (178) (132, 382, 383). 

These results show that in the phenylation of thiazole with benzoyl peroxide two secondary reactions enter in competition the attack of thiazole by benzoyloxy radicals, leading to a mixture of thiazolyl benzoates, and the formation of dithiazolyle through attack of thiazole by the thiazolyl radicals resulting from hydrogen abstraction on the substrate and from the dimerization of these radicals. This last reaction is less important than in the case of thiophene but more important than in the case of pyridine (398). 

TABLE III-37. COMPARISON OF THE RELATIVE REACTIVITIES (WITH RESPECT TO BENZENE) OF VARIOUS PYRIDINE SUBSTRATES towards PHENYL AND 2-THIAZOLYL RADICALS AT 70 TO... 

Alkylthiazoles react with ethylmagnesium bromide to give thiazolyl-magnesiurn compounds, as demonstrated for 4- and 5-methyithiazoles, 4-ethylthiazole. and 4,5-dimethylthiazole. The resulting addition compounds do not decompose at high temperature and pressure to yield alkylthiazoles as do the addition compounds obtained with pyridine. 

The higher reactivity of 2-halogenothiazoles with respect to halogenopyridines can be related to the different aromaticity of the two systems, less for thiazole than for pyridine, for example, the relatively stronger fixation of the tt bond in the thiazole than in the case of pyridine. As the data reported in Table V-1 (footnote a) indicates, the free thiophenol is more reactive than the thiolate anion toward the 2-halogenothiazoles. This fact should be considered when one prepares the thiazolyl sulfides. 

A useful method for the preparation of functionalised thiazoles has been described. Palladium catalysed cross coupling reactions between 4-thiazolyl-5-acetyl triflates 36 and alkynes afforded 4-alkynyl-5-acetylthiazoles 37 in good yields (56-82%). If 37 is then treated with ammonia in methanol, thiazolo[5,4-c]pyridines 39 are formed, probably via the intermediate imine 38 which then undergos a regioselective 6-endo dig cyclisation <99EJOC3117>. 

The incorporation of two terminal pyrazole or triazole rings into the ter-pyridine framework leads to a diversity of spin crossover behaviour not seen, for example, in the bis(thiazolyl) systems discussed above. It is likely that the presence of a non-coordinating >NH group and its involvement in hydrogen bonding gives rise to the striking effects. For a series of salts of [Fe(bpp)2]2+ (bpp is 2,6-bis(pyrazol-3- yl)pyridine 58) a marked dependence of the spin state on the anion and the extent of hydration has been observed [85-88]. 

Anodic regioselective fluorination of a-phenylsulphenylated ethyl acetates, 1-naphthalene and 2-pyridine derivatives [80], l-aryl-3-(phenylthio)oxindoles and 2-substituted-3-oxo-4-(phenylthio)-l, 2, 3,4-tetrahydroisoquinolines [81], 2-benzo-thiazolyl and 5-chloro-2-benzothiazolyl sulfides [82], a-(phenylsulfenyl)lactams [83], as well as various heterocycles such as thiolanones, oxathiolanones, dithi-olanones, 3Fl-l,4-benzoxathian-2-ones [84] in Et3N-3HF or Etr NF- HF [n = 3,4), has been reported. 

Ceftazidime Ceftazidime is l-[[7-[[(2-amino-4-thiazolyl)[(l-carboxy-l-methylethoxy) imino]acetyl]amino]-2-carboxy-8-oxo-5-thia-l-azabicyclo[4.2.0]oct-2-en-3-yl]methyl]pyridin-2-carboxylic acid (32.1.2.82). As is the case in synthesis of ceftriazone, the synthesis of ceftazidime requires the preliminary synthesis of two starting compounds. 7-Amino-3-(l-pyridinomethyl)cef-3-en-carboxylic acid dihydrochloride is used... 

Thiazoles are less electron-rich isosteres of pyridines and therefore it was speculated that compounds with such substitution may have improved metabolic stability [30]. The modeling of A-82200 in which the N-terminal pyridinyl group was substituted by a 4-thiazolyl moiety indicated that the 5-membered ring binds in the S3 subsite and can be further derivatized at the 2 position by an isopropyl group. The isopropyl functionality makes van der Waals contacts with Val82 and fills the hydrophobic part of the S3 subsite in nearly optimal fashion. 

The 8-oxo-7-phenylacetylamino-5-thia-l-aza-bicyclo[4.2.0]oct-l-ene-2-carboxylic acid benzhydryl ester is reacted with phosphorus pentachloride/pyridine reagent in methylene dichloride, and the reaction mixture is thereafter cooled to -35°C and treated with methanol to produce hydrochloride of 7-amino-8-oxo-5-thia-l-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester. This hydrochloride is reacted with 4-(3-aminothiophen-2-yl)-5-oxohex-3-enoic acid 3-methylbut-2-enyl ester. Then 7-[2-(2-benzoylamino-thiazol-5-yl)(3-tert-butyl-4,4-dimethylpent-2-enoxycarbonyl)-pent-2-enoylamino]-8-oxo-5-thia-l-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid synthesized is reacted with aluminum chloride in anisole and diluted hydrochloric acid and then with dimethylmalonate to give 5-thia-l-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid, 7-(((2Z)-2-(2-amino-4-thiazolyl)-4-carboxy-l-oxo-2-butenyl)amino)-8-oxo-, (6R,7R)- (Ceftibuten). 

To a solution of 1 kg (7 moles) of 2-amino-5-nitrothiazole in 5 L of pyridine (dried with potassium hydroxide) was added dropwise for 2-3 hours 8.5 moles of 2-thienoylchloride. N-(5-Nitro-2-thiazolyl)-2-thiophenecarboxamide was prepared as a yellow crystals with melting point 255-256°C. 

Livingstone and Nolan164) have prepared the tri-imine ligand 2,6-(dibenzothiazol-2-yl)pyridine (dbtp), which differs from 2,2, 2 -terpyridyl (terpy) in that it has benzo-thiazolyl moieties in place of the outer two pyridyl rings. Like terpy, dbtp coordinates... 

Intermolecular [4+2] cycloaddition strategies have also been used successfully. Moody and co-workers have reported the synthesis of a core piece of the thiopeptide antibiotics through a [4+2] cycloaddition <02CC1760>. For example, 2-azadiene 7 and 2-thiazolyl dienophile 8 were submitted to microwave heating (180 °C) for 15 minutes. The substituted pyridine product 9 was isolated in modest yield. Palacios has also reported an intermolecular [4+2] approach involving 2-azadienes <02JOC2131>. 

Bis(difluoromethoxy)phenyl]-2-[5-(2-(l-methyl-l-[(2-trimethylsilylethoxy)methoxy]ethyl)thiazolyl]ethyl pyridine... 

The di-pyridinyl derivative of the current invention, (+/—)-4- 2-[3,4-bis (difuoromethoxy)phenyl]-2-[5-(2-(l-hydroxy-l-(6-bromopyridin-3-yl)-2,2,2-trifluoro)-ethyl)thiazolyl]ethyl pyridine N-oxide, (II), has been prepared and is discussed (1). 

Pseudothiohydantoine, as acyclic intermediate, in reaction of o-halogeno acids or esters with thiourea, 232. See also 2-Amino-4-hydroxythiazole Pyridazines (4,7-dioxo-4,5,6,7-tetrahydro-thiazolo[4,5d]), preparation of, 206 Pyridine, electronic structure, 36, 39, 46 ultraviolet absorption, 47 thiazolylation of, 373 2-(4-Pyridyl)-4-carboxyethylthiazoie, from thioisonicotinamide and ethyl bromopyruvate, 198... 

GE2270A 394 is an antibiotic produced by Planobispora rosea ATCC 537731. It inhibits Gram-positive bacteria and anaerobes by acting on the protein synthesis elongation factor (EF) <1991JAN693, 1995T4867>. It contains proline, serine, glycine, two thiazolyl amino acids, and a heterocyclic centerpiece of a trisubstituted pyridine, all in a macrocyclic array. 

Thiazole (1,3-thiazole) possesses a pyridine-like N-atom and an S-atom as present in thiophene. The univalent radical is known as thiazolyl. The thiazole molecule is planar and the C-S bond... 

Furium. N[4-(5-Nitro-2-furanyl)-2-thiazolyl]acetamide, has demonstrated activity against bacilli and pathogenic enterobacteria (24). The product, prepared from thiourea and 2-bromo-l-(5-nitro-2-furanyl)ethanone followed by acetylation of the intermediate arninothiazole with acetic anhydride in pyridine (25), is marketed in several countries for both human and veterinary use. 

Thiopeptide antibiotics, thiazolyl peptides, naturally occurring sulfur-containing, highly modified, macrocyclic peptides. They share a number of structural motifs, including several heterocycles such as thiazoles, a dehydropiperidine, a pyridine, oxazoles, and indoles. Nearly aU of the thiopeptide antibiotics act as inhibitors of protein synthesis in bacteria. They are secondary metabolites produced by actino-mycetes, largely by the genus Streptomyces. A representative member of this family is thiostrepton [M. C. Bagleyetal., Chem. Rev. 2005, 105, 685]. 

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