Nitrate reduction with methanol

Oxidative phenolic coupling.1 The vancomycin antibiotics are polypeptides with bridging diphenyl ether groups. Evans et al. have shown in model systems such as 1 that cyclization to o-halophenolic peptides (2) can be accomplished by oxidation with thallium(III) nitrate in THF-methanol or CH2Cl2-methanol followed by CrCl2 reduction of a para-quinol intermediate (a). In three cases the yield of cyclic products was 40-48%. 

The ring opening of 2,2 -diphenyloxetane has been achieved using cerium(iv) ammonium nitrate (CAN) as a redox catalyst (Equation 7) <2003TL4585>. The first step involves oxidation of the oxetane by Ce(rv) to a cyclic radical cation. Equilibration to the ring-opened distonic version 42 with a stabilized cation, then quenching of the cation with methanol and reduction of the alkoxide radical by Ce(lll) to the anion, completes the catalytic cycle. 

Rehabilitation of groundwater 3.1.6.1 Reduction of nitrate with methanol... 

Alternatively, the gem-dibromo group represents a masked carbonyl group. Thus treatment of (8) with. sodium methoxide gives (9) when this is allowed to react with methanolic silver nitrate, the bromine atoms are replaced by methoxyl groups to generate the succinaldehyde ester (10). Hydrolysis of (10) leads to the aldehyde (11). Reduction with tris(triphenylphosphine)chlororhodium (1, 1252 2, 448-453 3, 325-329 this volume) effects decarbonylation to give (12). 

Dehydration Catalysts. In the production of amines from alcohols and ammonia or from alcohols and various amines, catalysts prepared by dehydrating alumina or silica gel are generally used. For specific reactions, these catalysts are promoted with various metals, their oxides or salts. For example, a dehydration catalyst has been made by incorporating aluminum phosphate in alumina gel prior to dehydrating the gel. An amination catalyst made by treating absorptive alumina with calcium and copper nitrates, followed by calcination and then reduction with hydrogen in a vapor-phase reactor, was used to produce an excellent yield of mono-methylaniline from aniline and methanol. ... 

Hydroxy-ffj-aminobenzoic acid is obtained by the nitration and reduction of -Hydroxy benzoic acid, which on esterification with methanol yields orthocaine. 

An interesting approach to chiral 2-amino-1,3-diols makes use of an asymmetric Staudinger reaction that incorporates the required functional groups into a jS-lactam nucleus. The condensation of imine 818 with benzyloxyketene produces jS-lactam 819 with 95% diastereo-selectivity [218]. After dearylation with cerric ammonium nitrate the amino polyol is released as an isoserine derivative (821) by cleavage of the jS-lactam with chlorotrimethylsilane in methanol [227] (Scheme 110). The amino group can be removed by conversion to isocyanide 823 followed by reduction with tris(trimethylsilyl)silane in the presence of AIBN, which furnishes erythro a,j8-dialkoxy ester 824 without racemization. 

Akunna, J.C. Bizeau, C. Moletta, R. (1993). Nitrate and nitrite reductions with anaerobic sludge using various carbon sources glucose, glycerol, acetic acid, lactic acid and methanol. Water Research, Vol.27, pp. 1303-1312... 

Thioetherification of PECH is feasibly performed in DA-solvents as already described in the patent (20J. For example, the highest substitution was obtained by the reaction of P(ECH-EO)(1 1 copolymer of epichloro-hydrin and ethylene oxide) and equimolar thiophenoxide in HMPA at 100°C for 10 h as DS 83% for sodium and 93% for potassium salts. The DS in our nucleophilic substitution was estimated by the elemental analysis as well as the titration of liberated chloride ion with mercuric nitrate (21). In the latter method, reacted medium was pretreated with hydrogen peroxide when the reductive nucleophiles which can react with mercuric ion were used. As described before for PVC, thiolation was also achieved conveniently with iso-thiuronium salt followed by alkaline hydrolysis without the direct use of ill-smelling thiolate. The thiolated PECH obtained are rubbery solids, soluble in toluene, methylene chloride, ethyl methyl ketone and DMF and insoluble in water, acetone, dioxane and methanol. 

The methyl substituent of 2-methyl-4,8-dihydrobenzo[l,2- 5,4-. ]dithiophene-4,8-dione 118 undergoes a number of synthetic transformations (Scheme 8), and is therefore a key intermediate for the preparation of a range of anthraquinone derivatives <1999BMC1025>. Thus, oxidation of 118 with chromium trioxide in acetic anhydride at low temperatures affords the diacetate intermediate 119 which is hydrolyzed with dilute sulfuric acid to yield the aldehyde 120. Direct oxidation of 118 to the carboxylic acid 121 proceeded in very low yield however, it can be produced efficiently by oxidation of aldehyde 120 using silver nitrate in dioxane. Reduction of aldehyde 120 with sodium borohydride in methanol gives a 90% yield of 2-hydroxymethyl derivative 122 which reacts with acetyl chloride or thionyl chloride to produce the 2-acetoxymethyl- and 2-chloromethyl-4,8-dihydrobenzo[l,2-A5,4-3 ]-dithiophene-4,8-diones 123 and 124, respectively. 

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