Benzaldehyde, phenylhydrazone

Benzaldehyde Phenylhydrazone. CeHsCHtN NHCeH. (Semi-micro Scale.)... 

Dissolve 0 3 ml. of glacial acetic acid in 2 ml. of water in a 25 ml. conical flask, and add 0 4 ml. (0 44 g.) of phenylhydrazine. Mix thoroughly to obtain a clear solution of phenylhydrazine acetate and then add 0 2 ml. (0 21 g.) of benzaldehyde. Cork the flask securely and shake the contents vigorously. A yellow crystalline mass of the hydrazone soon begins to separate. Allow to stand for 15 minutes, with occasional shaking, and then filter the solid product at the pump, wash first with very dilute acetic acid and then with water, and finally drain thoroughly. Recrystallise the material from rectified or methylated spirit, the benzaldehyde phenylhydrazone being thus obtained in fine colourless needles, m.p. 157 yield, 0 4 g. 

In 1973 two papers appeared almost simultaneously (73T101, 73CPB2026) describing the formation, as a minor product, of 3,4,5-trimethoxycarbonyl-l-phenylpyrazole (346) in the reaction between benzaldehyde phenylhydrazone and DMAD (EC=CE). To account for the formation of (346) George et al. (73T101) proposed a tentative mechanism (Scheme 29) involving a Diels-Alder reaction of type (a Figure 25), followed by a retro-Diels-Alder elimination of methyl phenylpropiolate (347). 

The only hydrazone previously converted to a nitrilimine is benzaldehyde phenylhydrazone 313 a which on treatment with Pb(OAc)4 in the presence of acrylonitrile (314 a) provided pyrazoline 315 a in 27% yield [90]. In all other... 

An identical compound is formed from benzil by the action of phenylhydrazine, and from benzaldehyde phenylhydrazone by autoxida-tion (Busch). The formation of osazones from a-hydroxyketones (and a-hydroxyaldehydes) will be discussed later (p. 298). 

Under the action of phenylhydrazine or 5-amino-3-phenylpyrazole on pyran 59b only benzaldehyde phenylhydrazone 271 is formed, probably, as the result of pyran retro-cleavage (82M53). A similar reaction with malononitrile, leading to pyran 59a, a product of formal displacement of a cyanoacetic moiety, possibly results from a similar cleavage (82M53) (Scheme 108). 

The reaction of aroylhydrazines with DMAD gives rise to the hydrazones of oxaloacetic ester, which undergo thermal transformation to the corresponding diaroylhydrazines. b. Hydrazones. Ethyl l,3,5-triphenylpyrazole-4-carboxylate has been reported to be formed in the reaction of benzaldehyde phenylhydrazone with ethyl phenylpropiolate. In a detailed investigation, George and co-workers have shown that aldehyde phenylhydrazones react with DMAD, yielding a mixture of pyrazoles and pyrazolines. Thus, in the reaction of benzaldehyde phenylhydrazone with DMAD, products such as dimethyl l,3-diphenylpyrazoline-4,5-dicarboxylate (129), dimethyl... 

Treatment of benzaldehyde l-allyl-[4-(methylsulfonyl)phenyl]hydrazone 251 with 45% sulfuric acid gave 252 rather than the expected l-allyl-l-[4-(methylsulfonyl)phenyl]hydrazine (Equation 63). Halogen-substituted hydra-zones gave similar results. Unsubstituted benzaldehyde phenylhydrazone gave normal hydrolysis <1996JHC213>. 

Nitrile imines generated by the benzaldehyde phenylhydrazone-chloramine-T route have been added to 1-azetines (219) (X = 0, S) (95,124). However, the adducts 220 (X=0, S) proved to be less stable than those derived from nitrile ylides (186) (94) and in many cases fragmented spontaneously to give the 5-butenyl-1,2,4-triazoles (221) as the isolated products. It was found, however, that... 

Die Oxidation von Hydrazonen mit organischen Persauren fiihrt in einigen Fallen zur Bildung von Azoxy-Verbindungen zur Umsetzung von Benzaldehyd-phenylhydrazon mit Persauren s. ds. Hdb., Bd. X/3, S. 475. 

A number of years ago it was observed that the perbenzoic acid oxidation of benzaldehyde phenylhydrazone afforded a high-melting product of low solubility which was termed benzaldehyde phenylhydrazone oxide. More recent work has shown that this, as well as related oxidation products of other phenylhydrazones, is, in fact, the cis isomer of the corresponding azoxy compounds [4, 7]. 

Heat amygdalin with dilute sulphuric acid under reflux for a short time. Remove benzaldehyde and hydrocyanic acid by steam distillation. Test for benzaldehyde (phenylhydrazone test) and hydrocyanic acid (Prussian blue test) in distillate, and for glucose (osazone test) in residue. 

Benzaldehyde phenylhydrazone with DM AD gave 8% of dimethyl 1,3-diphenylpyrazole-4,5-dicarboxylate (136) together with 35% of trimethyl pyrazoletricarboxylate (138), which the authors suggest is obtained from the primary adduct 137 by Michael addition of a second mole of DMAD followed by cleavage, as shown.129... 

Some interesting cycloadditions to 3-pyridyne (355) are illustrated in Scheme 102. IV-Phenylsydnone (356) gives (357), which spontaneously loses carbon dioxide to give the pyrazolopyridine (358). Benzaldehyde phenylhydrazone is oxidized by lead tetraacetate to the nitrilimine dipole (359), which also reacts with 3-pyridyne to give a pyrazolopyridine (360) (7160858). 

The hydrazone (XI) is the predominant form, and in acid and neutral solution no indication of either the azo- (X) or the ene-hydrazine form (XII) has been found. In alkaline solution, however, studies with tritium [56] have shown exchange both of the aldehyde hydrogen and of hydrogen atoms at the a-carbon, indicating the presence of both the forms (X and XII). The equilibrium constant in 0.1 M ethanolic KOH for the equilibrium benzyl phenyldiazene — benzaldehyde phenylhydrazone is about 10, but for monoalkylhydrazones of aliphatic carbonyl compounds a higher proportion of the azo form is found. Acetaldehyde propylhydrazone is thus in r-butanol containing 0.02 M potassium -butylate at 100°C in equilibrium with 3.7% of the azo form [57]. 

Further aminations are the formation of cyclohexanone oxime 0-methyl-ether from 34 and methanol, and of benzaldehyde phenylhydrazone from 3-phenyloxaziridine 41 and formanilide. ... 

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