Ketone semicarbazone derivative

The oxime has m.p. 96°. The ketone can be further purified by means of the semicarbazone derivative, which can be purified by crystallization and subsequently hydrolyzed by dilute hydrochloric acid. 

Because the hydrazone and semicarbazone derivatives of carbonyl compounds are often stable, crystalline solids, they used to be used to confirm the supposed identity of aldehydes and ketones. For example, the boiling points of... 

A molecular ion of m/z 70 means a fairly small molecule. A solid semicarbazone derivative and a negative Tollens test indicate a ketone. The carbonyl (CO) has mass 28, so 70-28 = 42, enough mass for only 3 more carbons. The molecular formula is probably C4H5O (mass 70) with two elements of unsaturation, we can infer the presence of a double bond or a ring in addition to the carbonyl. 

A method of almost universal applicability for the deoxygenation of carbonyl compounds is the Wolff-Kishner reduction While the earlier reductions were carried out in two steps on the derived hydrazone or semicarbazone derivatives, the Huang-Minlon modification is a single-pot operation. In this procedure, the carbonyl compound and hydrazine (hydrate or anhydrous) are heated (180-220 °C) in the presence of a base and a proton source. Sodium or potassium hydroxide, potassium-t-butoxide and other alkoxides are the frequently used bases and ethylene glycol or its oligomers are used as the solvent and proton source. Over the years, several modifications of this procedure have been used to cater to the specific needs of a given substrate. The Wolff-Kishner reaction works well with both aldehydes and ketones and remains the most routinely used procedure for the preparation of alkanes from carbonyl compounds (Table 9). This method is equally suitable for the synthesis of polycyclic and hindered alkanes. 

To further characterize the aldehyde, prepare its semicarbazone derivative (see Chapter 9, Preparation of Derivatives Aldehydes and Ketones).The semicarbazone derivative has a melting point of 215 °C. 

Synthesis from Aldehydes and Ketones. Treatment of aldehydes and ketones with potassium cyanide and ammonium carbonate gives hydantoias ia a oae-pot procedure (Bucherer-Bergs reactioa) that proceeds through a complex mechanism (69). Some derivatives, like oximes, semicarbazones, thiosemicarbazones, and others, are also suitable startiag materials. The Bucherer-Bergs and Read hydantoia syntheses give epimeric products when appHed to cycloalkanones, which is of importance ia the stereoselective syathesis of amino acids (69,70). 

Ketones are more stable to oxidation than aldehydes and can be purified from oxidisable impurities by refluxing with potassium permanganate until the colour persists, followed by shaking with sodium carbonate (to remove acidic impurities) and distilling. Traces of water can be removed with type 4A Linde molecular sieves. Ketones which are solids can be purified by crystallisation from alcohol, toluene, or petroleum ether, and are usually sufficiently volatile for sublimation in vacuum. Ketones can be further purified via their bisulfite, semicarbazone or oxime derivatives (vide supra). The bisulfite addition compounds are formed only by aldehydes and methyl ketones but they are readily hydrolysed in dilute acid or alkali. 

Nevertheless, derivatives of the 11-ketone have been prepared in special cases. Thus the ethylene ketal of 3a,20) -dihydroxypregnan-l l-one is obtained in 50% yield by prolonged reaction according to the direct procedure. Ketals of A/B aromatic-11-ketones are formed by exchange dioxolanation. 11 -Semicarbazones have not been prepared, but hydrazones... 

It yields on reduction dihydrocopaene, a compound boiling at 118° to 121° at 12 mm. By oxidation hy ozone or hy permanganate of potassium it yields a ketonic acid of the formula CijH Oj, which forms a semicarbazone melting at 221°. These derivatives characterise copaene AS a new sesquiterpene. Its characters, however, have only heen very slightly investigated at present. 

It is of interest to mention that in the presence of small amounts of sodium phosphate or arsenate the formation of 69 becomes the dominant reaction at pH 6.0 and 50°C the ratio 69/68 is 90/10. The strong catalytic effect of the phosphate and arsenate anions on the rate of formation of the ethano derivative 69 bears some analogy to the semicarbazone formation between ketone and amine, which is also found to be effectively catalyzed by these anions (68JA4319). 

Functional modifiers are used in binary nomenclature to name anhydrides, e.g. acetic anhydride for (CH3-C0)20, and derivatives of ketones and aldehydes such as oximes, hydrazones and semicarbazones, e.g. acetone oxime for (CH3)2C=NOH. 

Ketones of the 7r-deficient heterocycles form the usual derivatives, phenylhydrazones, semicarbazones, etc. The oximes undergo the Beckmann rearrangement (70JCS(B)1687). 

On reduction, nitroguanidine is converted first into nitrosoguanidine and then into aminoguanidine i.e. guanylhydrazine. The latter is used for the manufacture of tetrazene (p. 206), and in organic chemistry to form crystalline derivatives from aldehydes and ketones, just as semicarbazide forms semicarbazones. 

The sodium bisulfite addition compounds must have a free (or potentially free) ketone-type carbonyl group, since they readily form derivatives with typical ketone reagents such as semicarbazide and 2,4-dinitrophenylhydrazine.174 Decomposition of these derivatives with alkali gives the corresponding adrenochrome derivatives e.g., adrenochrome monosemicarbazone would be obtained from the semicarbazone of the adrenochrome-sodium bisulfite complex.174 If one accepts Tse and Oesterling s formulation of the adrenochrome-sodium bisulfite complex, the semicarbazone would probably have a basically similar structure (i.e. 82). This type of structure is more... 

One of the most characteristic reactions of the aminochromes is the ready formation of mono-derivatives with typical ketone reagents, e.g. semicarbazide, phenylhydrazine, etc. A relatively large number of derivatives of this nature have been prepared because of then-reported hemostatic activity (cf. refs. 2 and 3). Compounds of this type that had been described in the literature prior to December 1959 are listed in a previous review (Heacock3). Some further examples of this class of compounds have been described recently. They are N-ethylnoradrenochrome semicarbazone (84) (orange-red needles, m.p.180 215°)65 7-iodoadrenochrome methyl ether semicarbazone... 

The butanals form the conventional aldehyde hydrazone, semicarbazone, and dimedone-type derivatives. In the absence of other aldehydes and ketones, /2-butyraldehyde can be determined by addition of sodium bisulfite and the excess bisulfite determined with iodine or thiosulfate (34). 

An oxidized stage of isohexide nitrates, wherein the remaining hydroxyl group is transformed into the ketone, gives rise to a number of derivatives 161, such as oximes, semicarbazones, acyclic and cyclic acetals, and hydra-zones.154 Among them, 3-amino-2-hydroxypropyl-substituted oxime ethers... 

The neutral nitrogen compounds include tertiary aliphatic nitro compounds and aromatic nitro compounds amides (simple and substituted) nitrogen derivatives of aldehydes and ketones (hydrazones, semicarbazones, etc.) nitriles nitroso, azo, hydrazo and other intermediate reduction products of aromatic nitro compounds. The imides, primary and secondary nitro compounds, oximes and primary sulphonamides are weakly acidic nitrogen compounds. All the above nitrogen compounds and also the secondary sulphonamides, with few... 

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