4,5-Dimethylthiazol

Amino-5-methylthiazole does not react with diazotized p-nitroaniline in solutions acidified with acetic or hydrochloric acid (391). 2-Amino-4,5-dimethylthiazole with the diazonium salts of para-substituted anilines, however, gives product 193, involving reactivity of the exocyclic nitrogen (Scheme 122) (399). 

If 2-amino-4,5-dimethylthiazole is treated under such conditions 2-alkylamino-4.5-dimethylthiazoles are formed (202). 

Treating 5.5 g of 2-amino-4,5-dimethylthiazole HCl with 0.66 g of solid sodium hydroxide 15 min at 220°C yields 53% of 4.4. 5.5 -tetramethyT 2,2 -dithiazolylamine, whose structure w as proved by identification with the produa obtained from the reaction between dithiobiuret and 3-bromo-2-butanone (467). This result is comparable to the reaction between 2-aminopyridine and its hydrochloride to yield bis(pyridyl-2)amine (468). Gronowitz applied this reaction to 2-aminothiazole, refluxing it with its hydrochloride 4 hr in benzene and obtained the dimeric 2-aminothiazole (236). He proposed a mechanism (Scheme 143) that involves the addition of a proton to the 5-position of the ring to give 234. The carbocation formed then reacts on the 5-position of a second... 

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. 

Concerning nomenclature, fulvalene 2 and its related systems 1 and 3-6 are the parent structures of this class of heterocyclic cross-conjugated compounds. Both ring systems are numbered as shown in formula 9 (1,4,5,8-tetraazafulva-lene) beginning at the heteroatoms. Alternatively, as in the case of heptafulva-lene 10 (3,3 -diazaheptafulvalene), the numbers 1-7 and l -7 can be used.Tlie use of the name of the parent heterocycle connected by an olefinic double bond is often favored for the nomenclature of electron-rich olefines, for example, bis[3-(2,6-diisopropylphenyl)-4,5-dimethylthiazol-2-ylidene] for compound 51a (97LAR365). Similarly, azafulvalenes of type 11 and 12 can be re-... 

The deprotonation of 4,5-dimethylthiazole and addition of the resulting anion to aldehydes was demonstrated as early as 1948 (48HCA652) and 2-lithiothiazoles were later shown to react with aldehydes, ketones, methyl iodide, and epoxides... 

Diisopropylphenyl)-4,5-dimethylthiazol-2-ylidene as a stable carbene 99ACR913. 

Liu Y, Schubert D. Cytotoxic amyloid peptides inhibit cellular 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MMT) reduction by enhancing MTT formazan exocytosis. J Neurochem 1997 69 2285-2293. 

Most of the compounds in this series exhibited strong PDF inhibitory activity, low cytotoxicity, and potent antibacterial activity. Two compounds, VRC-4307 (111 Ri = cyclopentylethyl, R2 = 4,5-dimethylthiazol-2-yl) and VRC-4232 (111 Ri = isopentyl, R2 = 4,5-dimethylthiazol-2-yl), have been selected for further preclinical studies due to their promising therapeutic profiles. 

Reaction with MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide, Sigma ) was carried out in 96-well plate at 37 °C in thermostat (Carmichael et al., 1987). The cells were incubated for 0.5, 2, and 5 h in RPMI1640 medium in the presence or absence of fullerenes C60 samples, then MTT was added, and incubation continued for 2h. The content of generated formazane was evaluated by spectrophotometry at the wavelength of X = 570 nm at the digital spectrophotometer IFCO-2 (ABOTEK, Russia). 

In our laboratory, the viability of excised porcine buccal mucosa was assessed using histological evaluation and a 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) biochemical assay which has previously been used in assessing the viability of excised buccal mucosa and cornea [49, 50], Histological evaluation of tissue demonstrated that the buccal epithelium appeared viable up to 9 h postmortem, and this was supported by the MTT biochemical assay, which indicated that viability was maintained for up to 12 h [80], Therefore, we recommend that all permeation experiments using porcine buccal mucosa be performed within 9-12 h of animal death. 

The MTT method is simple, accmate and yields reproducible results. The key component is (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) or MTT. Mitochondrial dehydrogenases of viable cells cleave the tetrazolium ring, yielding prrrple formazan crystals insolnble in aqueous solutions. The crystals are dissolved in acidified isopropanol. The resrrlting ptuple solution is measured spectrophotometrically. An increase or decrease in cell number results in a concomitant... 

Dye oxidation (e.g., tetrazolium reductase activity with 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide, MTT 2-[4-iodophenyl]-3-[4-nitrophenyl]-5-[2,4-disulfophenyl]-2H tetrazolium monosodium salt, WST-1 3- (4,5 -carboxymethoxyphenyl) -2-(4-sulfophenyl)-2 H-tetra-zolium, MTS 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt, XTT 2,2 -di-p-nitrophenyl-5,5 -diphenyl-3,3 -(3,3 -dimethoxy-4,4 -diphe-nylenej-ditetrazolium chloride, NET), Alamar blue assays, ATP concentration (e.g., luciferase assay), oxygen consumption (e.g., oxygen electrodes, phosphorescent oxygen-sensitive dyes), mitochondrial protein and nucleic acid synthesis mitochondrial mass (e.g., mitotracker dyes) mitochondrial membrane potential (e.g., tetramethylrho-damine methyl ester, TMRM tetramethylrhodamine ethyl ester, TMRE)... 

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