Thiamine derivatives

This work supports the suggestion that sulfur dyes are complex thiamines derived generally from diphenylamine units (22). Depending on the conditions of the thionation, two or more thiamine units could be linked by sulfur to produce a typical sulfur blue (17, R = OH or NH2). 

Acid dye method for the analysis of thiamin, 18A, 73 electrophoretic separation and fluorometric determination of thiamin and its phosphate esters, 18A, 91 catalytic polarography in the study of the reactions of thiamin and thiamin derivatives, 18A, 93 preparation of thiamin derivatives and analogs, 18A, 141 preparation of the mono- and pyrophosphate esters of 2-methyl-4-amino-5-hydroxymethylpyrimidine for thiamin biosynthesis, 18A, 162 formation of the pyrophosphate ester of 2-methyl-4-amino-5-hydroxymethylpyrimidine by enzymes from brewers yeast in thiamin biosynthesis, 18A, 203 resolution, reconstitution, and other methods for the study of binding of thiamin pyrophos-... 

Thietanes have been obtained from thiamine derivatives and carbonyl sulfide. (Scheme 6). 

Based on the conventional analysis of the mechanism of decarboxylation of thiamin-derived intermediates, there is no role for a catalyst in the carbon-carbon bond-breaking step of this reaction. The thiazolium nitrogen is at its maximum electron deficiency with no available coordination sites. Ultimately, there is no place for a proton or other cation to position itself in order to promote the reaction by stabilizing a transition state that resembles the product of the reaction. Since there is no role for an acid, base, or metal to accelerate the decarboxylation of these intermediates by stabilizing the transition state for C-C bond-breaking, the means by which this could be achieved became a source of interest and speculation. 

Various thiamine derivatives were prepared on polymer support and were tested in C-C coupling reactions.40 The most straightforward approach was the alkylation of substituted 1,3-thiazoles with chloromethyl polystyrene resin yielding supported thiazolium chloride salts. Alternatively, resin-supported thiamine derivatives were constructed in a two-step process by alkylation of the primary alcohol with chloromethyl polystyrene followed by alkylation of the ring nitrogen yielding resin 12 (Fig. 8). Not only does this pathway introduce a spacer between the active thiamine... 

Winkler, W., Nahvi, A., and Breaker, R. R. (2002). Thiamine derivatives bind messenger RNAs directory to regulate bacterial gene expression. Nature 419, 952-956. 

Analytical Properties Useful for the separation of relatively polar compounds such as phenols, carboxylic acids, organic anions, nucleosides, alkylarylketones, chlorophenols, barbiturates, thiamine derivatives good stability under high and low pH reasonable mechanical integrity at high carrier pressure compatible with buffered liquid phases Reference 36-44... 

The reaction mixture was composed of 50 p.L of membrane preparation, 10 mM Hepes-Tris buffer (pH 6.8), 1.5 mM MgQ2, 1.5 mM EGTA, and 0.1 mM thiamine triphosphate in a total volume of 100 fiL. After 15 minutes of incubation at 25°C, the reaction was stopped by addition of 500 fiL of 6% trichloroacetic acid. The supemate obtained by centrifugation was extracted with 4 volumes of diethyl ether. The thiamine derivatives were transformed into fluorescent thiochromes by the addition of 50 fiL of oxidant [4.3 mJW K3Fe(CN)6 in 15% NaOH] to 80 fiL of sample. Thiamine diphosphatase activity was minimized by using magnesium as the metal and EGTA to chelate calcium. 

Bettendorff L (1996) A non-cofactor role of thiamine derivatives in excitable cells ... 

Betlendorff, L., Schoffentels, E., Naquet, R., Silva-Barra t, S., Riche, D., and Menini, C. (19S9). Phosphoiylated thiamine derivatives and cortical activity in the baboon Papio popio Effect of Intermittent light stimulation. /. Ncttrodicm. 53, BO-4)7. 

Wagner, H., Wagner-Hering, E. Lipophilic thiamine derivatives. Med. Klin. 62,... 

Kawasaki, H. Vitamin Bl and related compounds. LXXVI. Thiol-type thiamine derivatives 7. S-Acylation of thiazolium compounds. J. pharm. Soc. Japan 76, 702 (1956) Chem. Abstracts 51, 429 (1957). 

Volvert, M.L., Seyen, S., Piette, M., et al. (2008) Benfotiamine, a synthetic S-acyl thiamine derivative, has different mechanisms of action and a different pharmacological profile than lipid-soluble thiamine disulfide derivatives. BMC Pharmacol. 8, 10. 

Substituent effects in carbon-nitrogen cleavage of thiamin derivatives. Fragmentation pathways and enzymic avoidance of cofactor destruction. 

Thiamine derivatives inhibit glucose synthesis, transketolase (yeast), phosphodiesterase (snake venom), thiamine triphosphatase, thymidylate kinase. 

Luminescence properties of biochemically significant compounds can be used for analysis. The properties of thiamine derivatives published by Gibson and Turnbull are typical of the information needed for this purpose. 

Calculations have been carried out on the spectroscopy and excited-state energies and geometries of polyenes,84 the 1,5-cyclo-octadiyne radical cation,85 the visual chromophore, ll-c/s-retinal,8 polyene carbaldehydes,87 aromatic hydrocarbon anions and cations,88 trimethylenemethane,89 thiamine derivatives,80 porphyrins,91 lumiflavin,92 chlorophyll,93 nucleic acids,94 and ferrocene.95... 

Thiamine derivatives Thiamine diphosphate (D 10.4.5) Coenzyme of keto acid decarboxylase (C 4) and transketolases, in humans formed from thiamine (vitamin Bj)... 

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