Oxidation to carboxy

The dominant effect of carbonyl groups on the degradation of oxidized cellulose in an alkaline medium is evident also from the conversion of alkali-unstable oxidized celluloses into stable materials by reduction with sodium tetrahydroborate in a weakly alkaline medium, i.e., under conditions such that aldehyde groups are converted into alcoholic groups. The stability of oxidized celluloses is considerably enhanced also when carbonyl groups are oxidized to carboxy groups. 

It is also possible to oxidize two functional groups at once. In refluxing acetic acid, hydroxy groups and C = C bonds are both oxidized to carboxy groups however, the yields are low Under such harsh conditions. 

Both the aldehyde and 1° alcohol of an aldose are oxidized to carboxy groups by treatment with warm nitric acid, forming an aldaric acid. Under these conditions, D-glucose is converted to D-glucaric acid. 

Ethyl tram-5 a,9 a-dihydro-1 H- -benzazepine-1 -carboxy late (2), a photorearrangement product of ethyl 3,3a,7a,7b-tetrahydro-l//-cycIobut[6]indole-3-carboxylate (1), on treatment with tet-rachloro-l,2-benzoquinone in benzene undergoes oxidation to the l//-l-benzazepine 3.109... 

Pyridine-4-carboxylate is hydroxylated by Mycobacterium sp. strain INAl to 2,6-dihydroxypyridine-4-carboxylate. Two different hydroxylation enzymes were involved and were apparently Mo-dependent (Kretzer and Andreesen 1991). The formation of 2-ketoglutarate can, however, be rationalized equally as (3-oxidation to hexahydropyridine-2,3,6-trione-4-carboxy-CoA ester followed by hydrolysis. 

Also as noted above any substituents present have little effect upon such oxidations. In 2,2 -methylenedifuran (118) the rings are attacked simultaneously giving a tetramethoxy derivative.297 Even the bulk of the fert-butyl group has little effect.298 The only marked substituent effect is that exerted by an aromatic (benzene, thiophene, furan) residue which, if directly attached at the 2-position, promotes elimination instead of the addition of another methoxy group. The net process then becomes one of arylation, as when 2-(2-thienyl)furan (119) is oxidized to 120.298 There are reports that acetyl and carboxy groups can be ejected during oxidation, but that ester groups are usually retained.287... 

This cycloaddition-reduction-hydrolysis sequence was also used in an approach to butyrolactones related to ribonolactone (71). These compounds are inducing agents of hunger and satiety in mammalians. Here, a subsequent aldol 1,3-diol reduction was used, and the required carboxy function was established by oxidation of the aromatic ring with ruthenium tetroxide. Cycloaddition of benzonitrile oxide to allyl alcohol afforded an enantiomeric mixture of isoxazolines 55 and 56, which were treated with sodium hydride and methyl iodide to achieve separation by chromatography on cellulose triacetate (71). 0-Demethylation, followed by... 

THC undergoes metabolic degradation in the liver, where it is hydroxylated to 11-hydroxy tetrahydrocannabinol (THC-llOH). The latter, still with psychoactive activity, is oxidized to A9-THC-COOH, an inactive metabolite which is conjugated as 1 l-nor-A9-tetrahydrocannabinol-9-carboxy-glucuronide (A9-THC-COOH-glu), more hydrophilic metabolite and therefore easily excreted in the urine [32],... 

Kolbe synthesis — The definition and use of the terms - Kolbe synthesis, K. reaction, K. electrolysis, and K. process are not very clearly distinguished and often bear different nuances of meaning. Kolbe electrolysis or synthesis mainly accounts for the anodic oxidation of carboxylic acids or carboxylates, followed by a decarboxylation step, when concentrated aqueous solutions of the respective carboxylates are electrolyzed. Kolbe picked up earlier results from -> Faraday on the electrolysis of acetic acid or acetate solutions to CO2 and ethane [i] and continued these experiments during 1843-1845 with further homologs as, e.g., valerianic acid [ii]. The carboxy-late R-COO- is anodically oxidized to form an unstable radical R-COO, which is stabilizing via a decarboxylation reaction, leaving radical rest R ... 

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