Glyoxylates

VI.37. OXIDATION WITH LEAD TETRA-ACETATE n-BUTYL GLYOXYLATE... 

An interesting application of lead tetra acetate is to the jireparation of the otherwise dilliculty-accessiblo a-butyl glyoxylate (II) by oxidation of di-a-butyl i-tartrate (I) ... 

Store the n-butyl glyoxylate under nitrogen it undergoes autoxidation in air. The product decomposes on boiling (159-161°) at atmospheric pressure. 

A combination of the promoting effects of Lewis acids and water is a logical next step. However, to say the least, water has not been a very popular medium for Lewis-acid catalysed Diels-Alder reactions, which is not surprising since water molecules interact strongly with Lewis-acidic and the Lewis-basic atoms of the reacting system. In 1994, when the research described in this thesis was initiated, only one example of Lewis-acid catalysis of a Diels-Alder reaction in water was published Lubineau and co-workers employed lanthanide triflates as a catalyst for the Diels-Alder reaction of glyoxylate to a relatively unreactive diene . No comparison was made between the process in water and in organic solvents. 

Glyoxylic acid solution (protein detection) cover 10 g of magnesium powder with water and slowly add 250 mL of a saturated oxalic solution, keeping the mixture cool filter off the magnesium oxalate, acidify the filtrate with acetic acid and make up to a liter with water. 

Glyoxal [108-22-2] Glyoxal Resins Glyoxal resins Glyoxylic acid... 

Chiral glyoxylates have been used to effect of/z o-hydroxyalkylation of phenols via coordinative complexes. In this way, optically active 2-hydroxymandehc esters have been obtained with up to 94% diastereoselectivity (36). 

Glycohc acid also undergoes reduction or hydrogenation with certain metals to form acetic acid, and oxidation by hydrogen peroxide ia the presence of ferrous salts to form glyoxylic acid [298-12A], HCOCOOH, and ia the presence of ferric salts ia neutral solution to form oxaHc acid, HOOCCOOH formic acid, HCOOH and Hberate CO2 and H2O. These reduction and oxidation reactions are not commercially significant. 

This process has the advantage that, under the reaction conditions, the glyoxyl radical enters the aromatic guaiacol ring almost exclusively para to the phenoHc hydroxyl group. Tedious separation procedures are thus avoided. 

Woodward s total synthesis of cephalosporin C begins with L-cysteine (48) which establishes the chiral center at C-7. The cis geometry at C-6,7 is achieved in intermediate (49) which is cyclized to (50) by treatment with triethylaluminum. The dihydrothiazine ring is constructed by Michael addition to the condensation product of trichloroethyl glyoxylate... 

H-Cyclopenta[7,8]naphtho[2,3-6]furan-7-yl glyoxylate, 2,3,6,10-tetrahydro-6-hydroxy-6-methyl-3,10-dioxo-, methyl ester H NMR. 4, 560 (66JCS(C)743) Cyclopenta[6]quinoline, 6,7,8,9-tetrahydro- C NMR, 2, 122 (77JOC300, 77JOC2742)... 

Isothiazole-4,5-dicarboxylic acid, 3-phenyl-dimethyl ester synthesis, S, 150 Isothiazole-5-glyoxylic acid ethyl ester reduction, 6, 156 Isothiazole-4-mercurioacetate reactions, 6, 164 Isothiazole-5-mercurioacetate reactions, 6, 164 Isothiazoles, 6, I3I-I75 acidity, 6, 141 alkylation, 6, 148 aromaticity, S, 32 6, 144-145 basicity, 6, I4I biological activity, 6, 175 boiling points, 6, I43-I44, 144 bond fixation, 6, 145 bond orders, 6, I32-I34 calculated, 6, 133 bromination, S, 58 6, 147 charge densities, 6, 132-134 cycloaddition reactions, 6, 152 desulfurization, S, 75 6, 152 deuteration, S, 70... 

Di-(/)-chlorophenyl)-acetic acid has been made by the action of alcoholic potassium hydroxide on l,l-di-(/>-chlorophenyl)-2,2-dichloroethane by the action of barium hydroxide on DDT in ethylene glycol and by the condensation of chlorobenzene with glyoxylic acid. ... 

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