Phenyl hydrazine.hydrochloride

Prepare a solution of phenylhydrazine by dissolving 1 0 g. of phenyl-hydrazine hydrochloride and 1 5 g. of crystallised sodium acetate in 10 ml. of water if the resulting solution is turbid, filter. Add a solution of 0 5 ml. of cycZohexanone in 8 ml. of water to the reagent... 

To an ice-cooled (0°C to-—10°C) stirred flask containing 300 ml of water and 55.5 ml of concentrated hydrochloric acid is added dropwise over a 10 min period 33.5 gm (0.31 mole) of freshly distilled phenylhydrazine. Phenyl-hydrazine hydrochloride crystals precipitate as they are formed. Addition of... 

Like ammonia, these derivatives of ammonia are basic, and therefore react with acids to form salts hydroxylamine hydrochloride, HONH3 Cl phenyl-hydrazine hydrochloride, C,H5NHNH3 CI and semicarbazide hydrochloride, NH2C0NHNH < CI. The salts are less easily oxidized by air than the free bases, and it is in this form that the reagents are best preserved and handled. When needed, the basic reagents arc liberated from their salts in the presence of the carbonyl compound by addition of a base, usually sodium acetate. 

If this is heated with hydrochloric add, the sulphonic acid group is split off, and phenyl hydrazine hydrochloride is formed, which, on evaporation, crystallises out ... 

This reaction can be used for the recognition and detection of aldehydes and ketones. In order to prepare a hydrazone, formerly a solution of I part of phenyl hydrazine hydrochloride and ii parts of crystallised sodium acetate in 10 parts of water was used as a reagent. If this is added to an aldehyde or ketone, there is formed, in many cases at the ordinary temperature, but in others only on heating, the hydra-zone. Since, at present, perfectly pure free phenyl hydrazine may be purchased in the market, a mixture of equal volumes of phenyl hydrazine and 50 % acetic acid, diluted with three times its volume of water, is used as the reagent. 

Methyl-1,5-dlphanyl-1,2,4-trlazola (3).4 A mixture of phenyl hydrazine hydrochloride 1 (14 5 g, 0.11 mol), N-acetytbenzamide 2 (16.5 g, 0.1 mol) and NaOAc (10 g, 0.12 mol) in AcOH (30 ml) was refluxed for 10 h. The product was made efcaline wfh 10% NaOH solution and extracted with Et20 Evapotallon gave a pale yellow ofl which slowly solidified, mp 80-81 C. Recrystallization from 90% EtOH and petroleum ether aflorded 18 4 g of 3 (78%). 

Aliphatic aldehydes react quite rapidly with phenyl-hydrazine hydrochloride. Aliphatic ketones behave in the same manner towards the acetate, but react slowly, or not at all,with the hydrochloride. On this fact a method for their separation has been based. (Cf. p. 84), ... 

A mechanism of osazone formation utilizing the same intermediate (III) as the Weygand-Reckhaus mechanism (I-VII) has been proposed by Bloink and Pausacker The key step may be the formation of a cyclic transition state (III ) between the intermediate (III) and a molecule of phenyl-hydrazine hydrochloride which is reductively cleaved to yield the osazone (VIP) directly as well as ammonia and aniline simultaneously. 

Although phenyl azide can be prepared from phenyl hydrazine hydrochloride by addition of NaNO and HCl, we have used two other methods exclusively. If the ring contains a deactivating heteroatom, a direct nucleophilic substitution of a halogen by Njj in a suitable solvent is usually successful. If the ring is homoannular, then generation of the diazonium salt from nitrous acid, followed by substitution with Nh, produces the azide. For example, 9-azidoacridine can be prepared from 9-chloroacridine, and 3-azidoacridine is prepared from 3-aminoacridine. ... 

Erdos assayed his material for activity by noting its influence on tiie anemia produced in dogs and rabbits by the administration of phenyl-hydrazine (33). In the normal animal, the administration of phenyl-hydrazine hydrochloride (16 mg. per kg. body Aveight) lowered the red cell count 25 to 40 per cent in 48 to 72 hours, after Avhich time, spontaneous remission occurred. HoAvever, in those animals Avhich received liver preparations along Avith the phenylhydrazine, the ma, imal decrease of red cells Avas reached only after 96 to 120 hours. 

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