Methyl-thiazoles

Takatori (274) formylated 2-amino-4-methylthiazole with formic acid. When NHj is bubbled for 6 hr into a mixture of 2-amino-4-methyl-thiazole and propionic acid at 100°C, 2-propionamido-4-methylthiazole is obtained (275). 

In fuming sulfuric acid (20% oleum) 2 aminothiazole (16. 27. 375. 389) and 2-amino-4-methylthiazole (374. 390) are sulfonated in the 5-position. When this position is substituted as in 2-amino-5-methyl-thiazole (27, 391) very small amounts of 4-sulfonation occur. 

Picoline 129 2-Methyl-thiazole 128 2-Methvl-selen azole 149... 

Potts et al. (333) condensed dipolarophiles (DMA, dibenzoylacetylene, ethyl propiolate) with ylides (81) obtained by quaternization of 4-methyl-thiazole with an a-bromoketone or ester and subsequent deprotonation. In fact the 1 1 molar adduct obtained (82) rearranged to a pyr-rolothiazine (83). One example of this reaction is described Scheme 49. 

Under appropriate conditions 2-amino-4-alkylthiazoles are alkylated in the 5-position 2-acetylamino-4-methylthiazole reacts with dimethyl-amine and formaldehyde to afford the corresponding Mannich base (113) (372). 2-Amino-4-methyl-thiazole is alkylated in the 5-position by heat-... 

For example, N-propynylbenzamides lead to 2-pheny]-5-methyl-thiazole (10), Rj = phenyl, R2 = H. Rj = methyl (562). 

The Clemmensen reduction of 2-acetyl-5-methyl thiazole gives 2-ethyl-5-methyl thiazole (31) (Scheme 37). 

Me thy l-4-phenylthiazole-2)( 3-methyl-thiazole-2)monomethine cyanine iodide, 26... 

Analogously, the mesoionic jV-methyl thiazol-5-ones and l,3-dithiol-4-ones afforded A-methyl-4-pyridones and thiapyran-4-ones when reacting with diphenyl cyclopropenone and its thione261. Benzonitrile oxide apparently gives a 1,3-dipolar cycloaddition to the C=0 group of diphenyl cyclopropenone rationalizing the formation of triphenyl-l,3-oxazin-6-one 41626i ... 

We reported in the previous papers [8, 9] that the effect of the operational factors such as temperature and solvents on the polymorphic crystallization of a thiazole derivative - 2-(3 -Cyano-4-(2-methylpropoxy)-phenyl)-4-methyl-thiazole-5-car-boxylic acid (BPT) - which is an enzyme inhibitor. In this paper, we synthesized the esters of BPT and studied the effect of the molecular structure on polymorphic nucleation systemically, and at the same time we also examined the solvent effect on the polymorphic nucleation of the ester. 

Methyl ester (Me-est Methyl 2-(3-Cyano-4-(2-metylpropoxy)-phenyl)- 4-methyl-thiazole-5-carboxylate) and propyl ester (Pr-est Propyl 2-(3-Cyano-4-(2-methyl-propoxy)-phenyl)-4-methyl-thiazole-5-carboxylate) were synthesized (Fig. 11.1)... 

Methyl-2-(2-methyl-thiazol-4-yl)-5-nitro-imidazol862 Man riihrt cine Suspension von 210 mg (1 mmol)... 

Methyl-thiazol-4-yl)-4(5)-nitro-imida/.olin 20 w/Diethylether miteinem UberschuB Diazomethan 14 h bei 20°. Dann wird filtriert, das Losungsmittcl i. Vak. entfernt und der Riickstand aus Methanol umkri-stallisiert Ausbeute 146 mg (65%) Schmp. 144°. 

J 4-Hydroxy-2-methyl-1,1-dioxo-1,2-di hydro-116-benzo[e][1,2]thiazine-3-carboxylic acid (5-methyl-thiazol-2-yl)-amide, 4-hydroxy-2-methyl-A/-(5-methyl-2-thiazoyl)-2H-1,2-benzothiazine-3-carboxamide-1,1 -dioxide, C14H13N3O4S2, Mr 351.40, mp 264 °C (decomp.)... 

The addition of DMAD to 2-aminothiazole (25) gave 26, whereas propiolic ester gave 27, 28 and 29, all derived by Michael-type additions.549 Dunwell and Evans550,551 have also added acetylenic esters to 2-amino- (and 2-amino-4-methyl)thiazole and obtained 26 and 27 from DMAD and EP, and similar compounds from tetrolic and phenyl-propiolic esters. By independent synthesis, these compounds were shown not to have the isomeric structures derived by initial addition to the exocyclic nitrogen. 

Other thiohydroxamic acid derivatives have been used for the generation of radicals. Acyl derivatives of iV-hydroxythiazole-2-thione (75) have been explored by Barton as precursors for carbon radicals [86JCS(P1)39]. It has also been shown that similar precursors can be used for the generation of dialkylaminium cation radicals, N-hydroxy-4-methyl-thiazole-2-thione carbamates, TTOC carbamates 76 (91JOC1309). In contrast to... 

A solution of 15.7 g (92 mmol) of 2-isopropyl-4-(((N-methyl)amino)-methyl)thiazole in 200 ml of THF was combined with a solution of 20.5 g (69 mmol) of N-(((4-nitrophenyl)oxy)carbonyl)-L-valine methyl ester. The resulting solution was treated with 1.6 g of 4-dimethylaminopyridine and 12.9 ml (92 mmol) of triethylamine, heated at reflux for 2 h, allowed to cool, and concentrated in vacuo. The residue was taken up in CH2CI2, washed extensively with 5% aqueous K2C03, dried over Na2S04, and concentrated in vacuo. The resulting product mixture was purified by silica gel chromatography using chloroform as an eluent to provide 16.3 g (54%) of the desired compound. 

Amino-4-methyl-thiazole anion, behavior inNa/NH, 398... 

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