Hydrides oxide-nitrate, preparation

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

Catalysts suitable specifically for reduction of carbon-oxygen bonds are based on oxides of copper, zinc and chromium Adkins catalysts). The so-called copper chromite (which is not necessarily a stoichiometric compound) is prepared by thermal decomposition of ammonium chromate and copper nitrate [50]. Its activity and stability is improved if barium nitrate is added before the thermal decomposition [57]. Similarly prepared zinc chromite is suitable for reductions of unsaturated acids and esters to unsaturated alcohols [52]. These catalysts are used specifically for reduction of carbonyl- and carboxyl-containing compounds to alcohols. Aldehydes and ketones are reduced at 150-200° and 100-150 atm, whereas esters and acids require temperatures up to 300° and pressures up to 350 atm. Because such conditions require special equipment and because all reductions achievable with copper chromite catalysts can be accomplished by hydrides and complex hydrides the use of Adkins catalyst in the laboratory is very limited. 

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... 

A series of azophenol acerands 4 was prepared by condensation of crowned benzoquinones 10 with 2,4-dinitrophenylhydrazine in ethanol [7b], The quinone was derived from p-methoxyphenol (6) as shown in Scheme 1 [8]. By bis(hy-droxymethylation) (67% yield of 6, followed by methylation (92%) of the phenol group and Williamson-type reaction with ditosylates of oligoethyleneglycol in the presence of sodium hydride, crowned 1,4-dimethoxybenzene 9 was obtained in reasonable yields. Oxidative demethylation of 9 with ceric ammonium nitrate (CAN) in aqueous acetonitrile at 50 °C gave the desired crowned benzoquinones 10 in good yields. 

Z-Eburnamonine (XXXVI) has been produced by other reactions of vincamine. Oxidation of vincaminic acid (XL R = H) by means of ammoniacal silver nitrate was one way, and periodic acid fission of vincaminol was another (16). A different group of workers, who had probably attempted to prepare vincaminol by lithium aluminum hydride reduction of vincamine, obtained instead Z-ebumamonine in excellent yield (18). This has been rationalized as illustrated (partial formulas) by analogy with the base-induced decomposition of formic esters to carbon monoxide and alkoxide ion ... 

Reductive cyclization has been used in a novel, recent synthesis of the alkaloids ( )-isoretronecanol (22) and ( )-trachelanthamidine (23) by Borch and Ho. Condensation of the dianion derived from methyl acetoacetate with Z-l,4-dichlorobut-2-ene, followed by cyclization with sodium meth-oxide yielded the cycloheptenone ester intermediate (32) (Scheme 2). Reductive amination of this ketoester with sodium cyanoborohydride and ammonium nitrate gave a mixture of the diastereoisomeric aminoesters 33 and 34. Oxidation with osmium tetroxide and periodate, followed by reductive cyclization, again using sodium cyanoborohydride, gave the two pyrrolizidine esters 35 and 36 in a ratio of 1 2 [gas-liquid chromatography (GLC) analysis]. The esters were separated by preparative layer chromatography, and lithium aluminum hydride reduction of the individual esters gave the two pyrrolizidine alkaloids 22 and 23. 

Sohier et al. (1992) compared the hydrogenation properties of catalysts derived from RMC (M-Ni, Cu and Co) intermetallic precursors with those prepared from nitrate mixtures or by coprecipitation of rare-earth and metal hydroxides. These catalysts were also compared to a Ni/CeCh catalyst and mixtures of pure Ni with rare-earth oxide or hydroxides. The intermetallic compounds were submitted to hydriding-dehydriding cycles, then oxidized by calcination at 293 K (partially oxidized) and at 703 K (fully oxidized). The largest surface areas for oxides were obtained by the coprecipitation route. 

All of the members of the final review team contributed, if not text, then comments to all of the chapters of the book. Their primary responsibilities for the different sections/chapters were divided as follows. Paul Brown prepared the introduction, and the sections on elemental zirconium, the zirconyl ion, the gaseous zirconium oxides, zirconium hydride, the halogen compounds and complexes, the chalcogen compounds and complexes, the Group 15 compounds and complexes, zirconium carbides and silicates. He was assisted by Christian Ekberg in the interpretation of aqueous zirconium complexes in these sections. Some initial work was done by Ken Jackson on the zirconium sulphate, nitrate and phosphate compounds and complexes. Bernd Grambow was responsible for the drafting of the sections on zirconium hydrolysis, the ion and the section on crystalline and amorphous zirconium oxides. Enzo Curti drafted the section on the zirconium carbonates. 

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