2.4- Dimethyl-1,3-thiazole

Chapter V. Quinaldine (V,2) 2-methyl-, 2 5-dimethyl- and 2-acetyl-thiophene (V,8-V,10) 2 5-dimethyl and 2 4-dimethyl-dicarbethoxy-p3nrole (V,12-V,13) 2-amino- and 2 4 dimethyl-thiazole (V,15-V,16) 3 5-dimethyl-pyrazole (V,17) 4-ethylp3rridine (from pyridine) (V,19) n-amyl-pyridines from picolines) (V,28) picolinic, nicotinic and isonicotinic acid (V,21-V,22) (ethyl nicotinate and p-cyanop3n idine (V,23-V,24) uramil (V,25) 4-methyl-(coumarin (V,28) 2-hyi-oxylepidine (V,29). 

Acheson et al. (336) by the condensation of DMA with 2,4-dimethyl-thiazole in THF (Scheme 56). As Reid et al. (335) first proposed, the adduct of 2,4-dimethylthiazole with DMA in DMF (93) results from the normal cyclo-addition with rearrangement (Scheme 57). The conclusive demonstration of this structure was recently given by Acheson et al. (339)... 

All the early literature concerning thiazoles mentions numerous metallic complex-salts formed by addition to the thiazole of the aqueous solution of the metal salt and that could be used for identification purposes. The most usual complexes so obtained are platinum double salts, for example, (4-methylthiazole HC1)2 PtCU (m.p. deep 204°C) (25), or mercuric chloride derivatives, for example, 2,4-dimethyl-thiazole 2 HgCl (m.p. deep 176-177°C) (458). 

Schatzmann, in 1891, tried to prepare 2-thiazolines by hydrogenation of thiazoles and by the action of sodium and ethanol on 2,4-dimethyl-thiazole, 2-methylthiazole, and 2-methyl-4-phenylthiazole (476). None of these substrates was reduced to thiazoline the second gave no reaction and the first underwent ring cleavage, leading to a mixture of n-propylmercaptan and ethylamine (Scheme 90). Three years later the same... 

There was no loss in flavorant at a 100 mg level when either whole soy or soy 7S protein was used, but there was a 14-24 percentage loss when 11S protein was used. Only soy 11S protein affected the substituted pyrazine content of the mixture at all addition levels. The higher the substituted pyrazine congener, the smaller was the percentage loss with any of the protein types. At the 500 mg level, only about 50% of the amount of any of the methyl pyrazines in the control was recovered from either soy 7S or 11S protein while 70% was recovered from whole soy protein. These results greatly extend the initial work reported by Palkert and Fagerson (11J who determined that about 75% of dimethyl thiazole, a sulfur-nitrogen heterocycle, was recovered from dry, textured soy protein. 

Thiazole sulfonation occurs only under forcing conditions the action of oleum at 250 °C for 3 hours in the presence of mercury(II) sulfate leads to 65% formation of 5-thiazole sulfonic acid. 4-Methyl- and 2,4-dimethyl-thiazoles undergo sulfonation at the 5-position under equally forcing conditions (oleum, 200 °C). 2-Aminothiazole is sulfonated at low... 

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

This assay was developed and used in anti-HIV screening programs (Pauwels et al. 1988). The tetrazolium salt MTT [3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyltetrazolium bromide] is converted to dark blue formazan by living cells but not by dead cells or culture medium. These assays are carried out in 96-well plates. 

Thiazole, methyl-5-propyl-Thiazole, 2-butyl-Thiazole, 2-ethyl-Thiazole, 2-ethyl-5-methyl-Thiazole, 2-methyl-Thiazole, 2-(3-methylbutyl)-Thiazole, 2-(1-methylethyl)-Thiazole, 2-(1-methylpropyl)-Thiazole, 2-(2-methylpropyl)-Thiazole, 2,4-diethyl-Thiazole, 2,4-dimethyl-Thiazole, 2,4,5-trimethyl-Thiazole, 2,5-diethyl-4-methyl-Thiazole, 2,5-dimethyl-Thiazole, 4-ethyl-2-methyl-Thiazole, 4-ethyl-5-methyl-Thiazole, 4-methyl-... 

Thiazole, 4-(2-methylpropyl)-Thiazole, 4-propyl-Thiazole, 4,5-dimethyl-Thiazole, 5-ethyl-Thiazole, 5-ethyl-2,4-dimethyl-Thiazole, 5-ethyl-2-methyl-Thiazole, 5-ethyl-4-methyl-Thiazole, 5-methyl-... 

Two hundred and sixty-eight compounds were identified in this study as components of YEs, and they are listed by class in Table II. Sixty-seven of the compounds identified contained sulfur (75) and are listed in Table III. The 34 compounds identified for the first time as components of YEs are denoted by ( ) in Table III. Twenty-eight of the newly identified components of YE were detected in Sample C while seven were identified in Sample B. None could be identified from Sample A. Eighteen of the newly-identified representatives listed are thiazoles. Some of the thiazoles reported in this study, i.e., thiazole, 4,5-dimethylthiazole and 2,4-dimethyl-5-ethylthiazole possess meaty qualities at certain dilutions (76). 2,4-Dimethyl-thiazole, which has not previously been reported as a component of YE aroma, possesses a "meaty, cocoa" or "slmnky-oily" odor (76). Other thiazoles listed in Table III may be expected to contribute green, nutty and vegetable-like notes (76). 

Nakano, T. Martin, A. Mass Spectro-metiic Fragmentation of the Oxetanes of 3,5-Dimethylisoxazole, 2,4-Dimethyl-thiazole, and 1-Acetylimidazole. Org. Mass Spectrom. 1981,16,55-61. 

Reduction of 2.4-dimethyl-5-nitrothiazole with activated iron gives a product that after acetylation yields 25% 2.4-dimethyl-5-acetamido-thiazole (58). The reduction of 2-methyl 5-nitrothiazole is also reported (351 to give a mixture of products. The nitro group of 2-acetylhydrazino-5-nitrothiazole is reduced by TiCl in hydrochloric acid or by Zn in acetic acid (591. 

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