The carbonyl group is not ketonic in character since it yields neither an oxime nor hydrazone.
The carbonyl oxygen may also be replaced by the oxime group,: N OH; thus the acids yield the hydroxamic acids, R C(OH): NOH, and the acid-amides the amidoximes, R C(NH 2): NOH.
Beckmann, Ber., 1886, 1 9, p. 9 8 9; 188 7, 20, p. 2580), yielding as final products an acid-amide or anilide, thus: RC(:N OH)R'-RC(OH) :NR' ---> As regards the constitution of the oximes, two possibilities exist, namely >C: NOH, or > C' ?, and the first of these is presumably correct, since on alkylation and subsequent hydrolysis an alkyl hydroxylamine of the type NH 2 OR is obtained, and consequently it is to be presumed that in the alkylated oxime, the alkyl group is attached to oxygen, and the oxime itself therefore contains the hydroxyl group. It is to be noted that the oximes of aromatic aldehydes and of unsymmetrical aromatic ketones frequently exist in isomeric forms. This isomerism is explained by the HantzschWerner hypothesis (Ber., 1890, 23, p. II) in which the assumption is made that the three valencies of the nitrogen atom do not lie in the same plane.
HO N Aldoximes are generally obtained by the action of hydroxylamine hydrochloride on the aldehyde in presence of sodium carbonate; the oxime being then usually extracted from the solution by ether.
Soc., 18 9 8, 73, p. 35 2) as a colourless liquid by the addition of hydroxylamine hydrochloride to an aqueous solution of formaldehyde in the presence of sodium carbonate; the resulting solution was extracted with ether and the oxime hydrochloride precipitated by gaseous hydrochloric acid, the precipitate being then dissolved in water, the solution exactly neutralized and distilled.
Benzaldoximes.-The a-oxime (benz-anti-aldoxime) is formed by the action of hydroxylamine on benzaldehyde.
Mesityl oxime, (CH 3) 2 C: CH C(: NOH)CH 3, exists in two modifications.
When boiled for some time with caustic soda, it is converted into the oily a-oxime, which boils at 83-84° C. (9 mm.).
The a-oxime, on long continued boiling with a concentrated solution of a caustic alkali, is partially decomposed with formation of some acetone and acetoxime (C. Harries, Ber., 1898, 31, pp. 1381, 1808; 18 99, 32, p. 1 33 1).
Benzophenone oxime, CeHSC (:NOH)C 6 H 5, exists only in one modification which melts at 140° C.; whereas the unsymmetrical benzophenones each yield two oximes.
Wohl forms the oxime and converts it into an acetylated nitrile by means of acetic anhydride and sodium acetate; ammoniacal silver nitrate solution removes hydrocyanic acid and the resulting acetate is hydrolysed by acting with ammonia to form an amide, which is finally decomposed with sulphuric acid.
CH 2 OH CH20H CH20H CH20H (CH OH) 3 -> 01 OH) 3 -> (CH OH) 3 --> (CH OH)3 CH OH CH OH CH OH CHO CHO CH:NOH CN Hexose -p Oxime -> Nitrile -> Pentose.
The ketone, dihydroxyacetone, CH 2 OH CO CH 2 OH, was obtained by Piloty by condensing formaldehyde with nitromethane, reducing to a hydroxylamino compound, which is oxidized to the oxime of dihydroxyacetone; the ketone is liberated by oxidation with bromine water: 3H CHO + CH 3 NO 2 -- (CH 2 OH) 3 C NO 2 - (CH 2 OH) 3 C NH OH -- (CH 2 OH) 2 C: NOH - > (CH20H)2CO.
It behaves more as a ketone than as a quinone, since with hydroxylamine it yields an oxime, and on reduction with zinc dust and caustic soda it yields a secondary alcohol, whilst it cannot be reduced by means of sulphurous acid.
It possesses all the characteristic properties of an aldehyde; being readily oxidized to benzoic acid; reducing solutions of silver salts; forming addition products with hydrogen, hydrocyanic acid and sodium bisulphite; and giving an oxime and a hydrazone.
Two are known, namely 4-nitroso-a-naphthol or 13; a-naphthoquinone-oxime, formed by the action of nitrous acid on a-naphthol or of hydroxylamine hydrochloride on a-naphthoquinone (H.
Amino-cyclo-heptane (suberylamine) is obtained by the reduction of suberone oxime or by the action of sodium hypobromite on the amide of cycloheptane carboxylic acid.
When heated with fuming hydriodic acid to 300° C. it yields normal pentane and ammonia, and hydrogen peroxide oxidizes it to glutarimide and to a piperidinium oxide or oxime (R.
It forms a hydrazone with phenyl hydrazine, and an oxime with hydroxylamine.
Stereo-Isomerism); thus parachlorbenzophenone oxime exists in two different forms (V.
It behaves as a powerful reducing agent, and on hydrolysis with dilute mineral acids is decomposed into formaldehyde and hydroxylamine, together with some formic acid and ammonia, the amount of each product formed varying with temperature, time of reaction, amount of water present, &c. This latter reaction is probably due to some of the oxime existing in the form of the isomeric formamide HCO NH 2.