METAL PYRUVATE

METAL NITROPHENOXIDES, METAL OXALATES METAL PYRUVATE NITROPHENYLHYDRAZONES metal OXOHALOGENATES (anion an oxo derivative of a halogen) metal oxometallates (anion an oxo derivative of a metal) metal oxonon-METALLATES (anion an oxo derivative of a non-metal) peroxoacid SALTS (anion a peroxo derivative of a metal or non-metal) There is a separate entry for... 

METAL OXONON-metallates (anion an oxo derivative of a non-metal) metal pyruvate nitrophenylhydrazones... 

Metal cyanides(and cyano complexes), 216 Metal derivatives of organofluorine compounds, 217 IV-Metal derivatives, 218 Metal dusts, 220 Metal fires, 222 Metal fulminates, 222 Metal halides, 222 Metal—halocarbon incidents, 225 Metal halogenates, 226 Metal hydrazides, 226 Metal hydrides, 226 Metal hypochlorites, 228 Metallurgical sample preparation, 228 Metal nitrates, 229 Metal nitrites, 231 Metal nitrophenoxides, 232 Metal non-metallides, 232 Metal oxalates, 233 Metal oxides, 234 Metal oxohalogenates, 236 Metal oxometallates, 236 Metal oxonon-metallates, 237 Metal perchlorates, 238 Metal peroxides, 239 Metal peroxomolybdates, 240 Metal phosphinates, 240 Metal phosphorus trisulfides, 240 Metal picramates, 241 Metal pnictides, 241 Metal polyhalohalogenates, 241 Metal pyruvate nitrophenylhydrazones, 241 Metals, 242 Metal salicylates, 243 Metal salts, 243 Metal sulfates, 244 Metal sulfides, 244 Metal thiocyanates, 246 Metathesis reactions, 246 Microwave oven heating, 246 Mild steel, 247 Milk powder, 248... 

Hydrazinium metal pyruvates [N2H5]2M[CH3COCOO]4, where M = Co or Ni, are prepared from aqueous solution containing a mixture of the respective salts, pyruvic acid, and hydrazine hydrate [11]. The magnetic moments and electronic spectra of the complexes suggest a high-spin... 

Raju, B. and Sivasankar, B.N. (2009) Spectral, thermal, and X-ray studies on some new bis and tris-hydrazine and hydrazinium metal pyruvates. Journal of Thermal Analysis and Calorimetry, 98, 371-376. 

Due to mechanistic requirements, most of these enzymes are quite specific for the nucleophilic component, which most often is dihydroxyacetone phosphate (DHAP, 3-hydroxy-2-ox-opropyl phosphate) or pyruvate (2-oxopropanoate), while they allow a reasonable variation of the electrophile, which usually is an aldehyde. Activation of the donor substrate by stereospecific deprotonation is either achieved via imine/enamine formation (type 1 aldolases) or via transition metal ion induced enolization (type 2 aldolases mostly Zn2 )2. The approach of the aldol acceptor occurs stereospecifically following an overall retention mechanism, while facial differentiation of the aldehyde is responsible for the relative stereoselectivity. 

The Fe(III) complexes of the dianion of pyruvic acid thiosemicarbazone (thpu2- Fig. 7), (cation+)[Fe(thpu)2]-nH20, are very similar to those of the salicylaldehyde derivatives (Fig. 6) discussed above. The spin state properties are quite sensitive to changes in the counter-cation (typically an alkali-metal cation or a protonated nitrogenous base) and the lattice water content of the material. The parent compound, NH4[Fe(thpu)2], is low spin at room temperature [113]. Li[Fe(thpu)2]-3H20 is also low spin but K[Fe(thpu)2] 2-H20 shows almost complete spin crossover between 80 and 300 K [108]. 

Marcus theory, first developed for electron transfer reactions, then extended to atom transfer, is now being applied to catalytic systems. Successful applications to catalysis by labile metal ions include such reactions as decarboxylation of oxaloacetate, ketonization of enolpyru-vate, and pyruvate dimerization (444). 

The addition of an enolsilane to an aldehyde, commonly referred to as the Mukaiyama aldol reaction, is readily promoted by Lewis acids and has been the subject of intense interest in the field of chiral Lewis acid catalysis. Copper-based Lewis acids have been applied to this process in an attempt to generate polyacetate and polypropionate synthons for natural product synthesis. Although the considerable Lewis acidity of many of these complexes is more than sufficient to activate a broad range of aldehydes, high selectivities have been observed predominantly with substrates capable of two-point coordination to the metal. Of these, benzy-loxyacetaldehyde and pyruvate esters have been most successful. 

Cinchona-modified platinum catalysts received special interest mainly because of to the results obtained for the hydrogenation of methyl pyruvate (MP) or ethyl pyruvate. E.e. s up to 80% or even higher (98% for ethyl pyruvate) made this system one of the most interesting ones from the application point of view. At present, 5% Pt/alumina with low dispersion (metal particles > 2 nm) and a rather large pore volume constitutes one of the best catalysts commercially available. 

---