Oximes carbonyl groups

Hydroxylamine condenses with the carbonyl group of an aldehyde or ketone to form an oxime ... 

For oximes, the word oxime is placed after the name of the aldehyde or ketone. If the carbonyl group is not the principal group, use the prefix hydroxyimino-. Compounds with the group Z = N—OR are named by a prefix alkyloxyimino- as oxime O-ethers or as O-substituted oximes. Compounds with the group r C=N(0)R are named by adding A-oxide after the name of the alkylideneaminc compound. For amine oxides, add the word oxide after the name of the base, with locants. For example, C5H5N—O is named pyridine A-oxide or pyridine 1-oxide. 

Pyridazine aldehydes and ketones with the carbonyl group at the ring or in a side chain react in the usual manner. They form hydrazones, semicarbazides, oximes, etc. Side-chain aldehydes can be easily oxidized to pyridazinecarboxylic acids with silver nitrate and side-chain ketones are oxidized to carboxylic acids by treatment with potassium permanganate or hydrogen peroxide. 

The carbonyl group forms a number of other very stable derivatives. They are less used as protective groups because of the greater difficulty involved in their removal. Such derivatives include cyanohydrins, hydrazones, imines, oximes, and semicarbazones. Enol ethers are used to protect one carbonyl group in a 1,2- or 1,3-dicarbonyl compound. 

In a synthesis of sativene a carbonyl group was protected as a 2,4-DNP while a double bond was hydrated with BH3/H202/0H . Attempted protection of the carbonyl group as a ketal caused migration of the double bond protection as an oxime or oxime acetate was unsatisfactory since they would be reduced with BH3. 

The reactions shown below were used in a synthesis of perhydrohistrionicotoxin the carbonyl groups were protected as an oxime and an O-benzyl oxime. ... 

In a prostaglandin synthesis a carbonyl group was protected as an oxime in which the hydroxyl group was protected against Collins oxidation by the phenylthiome-thyl-group. The phenylthiomethyl group is readily removed to give an oxime that is then cleaved to the carbonyl compound. ... 

NaN02, 1 N HCl, CH3OH, H2O, 0°, 3 h, 76% yield. In the last step of a synthesis of erythronolide A, acid-catalyzed hydrolysis of an acetonide failed because the carbonyl-containing precursor was unstable to acidic hydrolysis (3% MeOH, HCl, 0°, 30 min, conditions developed for the synthesis of erythronolide B). Consequently, the carbonyl group was protected as an oxime, the acetonide was cleaved, and the carbonyl group was regenerated. 

During hydrogenation, intermediate aromatic hydroxylamines may undergo various cyclization reactions in molecules containing a suitably disposed carbonyl group, or carbonyl derivative, such as an oxime (13). The cyclized product may or may not maintain the N—OH bond, depending on the solvent, the catalyst, and the electrophilicity of the carbonyl (27,28,29,32,67,68). 

It is of interest to note that attachment of a basic side chain on carbon of an isomeric dibenzazepine affords a compound in which anticholinergic activity predominates, elantrine (50). Reaction of anthra-quinone (45) with the Grignard reagent from 3-chloro-N,N-dimethylaminopropane in THF in the cold results in addition to but one of the carbonyl groups to yield hydroxyketone 46. This is then converted to oxime 47 in a straightforward manner. Treatment of that intermediate with a mixture of phosphoric and polyphosphoric acids results in net dehydration of... 

The carbonyl group of the pyrrolizinone lc has been reduced with NaBH4 to give alcohol 171 <2004JME1448>. Condensation of lc with hydroxylamine in pyridine gave the oxime 172 in 95% yield. The latter was substituted by a chloramine chain to form the corresponding oxime ether 173 (Scheme 22) <2004JME1448>. 

For oximes, the word oxime is placed after the name of the aldehyde or ketone. If the carbonyl group is not the principal group, use the prefix hydroxyimino-. Compounds with the group —OR... 

The first step involves the above considered a, 3-C,C-coupling reaction of two different AN molecules the second step, selective deoximation of the 3-nitro oximes obtained the third step, selective reduction of the carbonyl group. 

Recently a quantitative method for the determination of carbonyl groups in oxidized xylan has been developed.106 The method involves the reaction of the carbonyl group with O-methylhydroxylamine hydrochloride to form the corresponding oxime with the liberation of one mole of titratable acid. 

Derivatization of carbonyl groups (reduction or formation of N,N-dimethyl-hydrazones or oximes)... 

---