Phenyl diazonium chloride

It reduces phenyl diazonium chloride to phenylhydraiiiiic hydrochloride. ... 

Note on the laboratory preparation of monoethylaniline. Although the laboratory preparation of monomethyl- or monoethyl-aniline is hardly worth whUe, the following experimental details may be useful to those who wish to prepare pure monoethylaniline directly from amline. In a flask, fitted with a double surface reflux condenser, place 50 g. (49 ml.) of aniline and 65 g. of ethyl bromide, and boU gently for 2 hours or until the mixture has almost entirely sohdified. Dissolve it in water and boil off the small quantity of unreacted ethyl bromide. Render the mixture alkaUne with concentrated sodium hydroxide solution, extract the precipitated bases with three 50 ml. portions of ether, and distil off the ether. The residual oil contains anihne, mono- and di-ethylaniline. Dissolve it in excess of dilute hydrochloric acid (say, 100 ml. of concentrated acid and 400 ml. of water), cool in ice, and add with stirring a solution of 37 g. of sodium nitrite in 100 ml. of water do not allow the temperature to rise above 10°. Tnis leads to the formation of a solution of phenyl diazonium chloride, of N-nitrosoethylaniline and of p-nitrosodiethylaniline. The nitrosoethylaniline separates as a dark coloured oil. Extract the oil with ether, distil off the ether, and reduce the nitrosoamine with tin and hydrochloric acid (see above). The yield of ethylaniline is 20 g. 

Phenylarsonic acid may be obtained from the reaction between phenyl-diazonium chloride and sodium arsenite in the presence of a trace of copper sulphate ... 

Chlorobenzene. Prepare a solution of phenyldiazonium chloride from 31 g. (30 -5 ml.) of aniUne, 85 ml. of concentrated hydrochloric acid, 85 ml, of water, and a solution of 24 g. of sodium nitrite in 50 ml. of water (for experimental details, see Section IV,60). Prepare cuprous chloride from 105 g. of crystallised copper sulphate (Section 11,50,1), and dissolve it in 170 ml. of concentrated hydrochloric acid. Add the cold phenyl diazonium chloride solution with shaking or stirring to the cold cuprous chloride solution allow the mixture to warm up to room temperature. Follow the experimental details given above for p-chlorotoluene. Wash the chlorobenzene separated from the steam distillate with 40 ml. of 10 per cent, sodium hydroxide solution (to remove phenol), then with water, dry with anhydrous calcium chloride or magnesium sulphate, and distil. Collect the chlorobenzene (a colourless liquid) at 131-133° (mainly 133°), The yield is 29 g. 

Unsymmetrical diaryls may be prepared by treating an aryl diazonium salt solution with sodium hydroxide or sodium acetate in the presence of a liquid aromatic compound. Thus 2-chlorodiphenyl is readily formed from o-chloro phenyl diazonium chloride and sodium hydroxide solution (or sodium acetate solution) in the presence of benzene ... 

A nitro group in the 4-position markedly increases the instability of the isoxazole ring in alkaline medium. This effect is clearly demonstrated by 3,5-dime thy 1-4-nitroisoxazole. Whereas 3,5-dimethyl-isoxazole is not affected by alkali, its 4-nitro-derivative (134) is cleaved by 2% sodium hydroxide. The structure of the product was proved by its conversion into a triazole (135) with phenyl diazonium chloride, according to the original authors. ... 

Zur Aminosaure-Herstellung geeignete 2-Hydrazono-carbonsauren lassen sich auf mch-reren Wegen synthetisieren, z. B. aus cyclischen 3-Oxo-carbonsaure-estem durch oxidative Spaltung mit Phenyl-diazonium-chlorid (Japp-Klingcmann-Reaktion2,5). 

The derivative (22) has been prepared in two ways (Scheme 4). The diazo compound (59), made by diazotization of the 3,4,5-triamino-l,2,6-thiadiazine 1,1-dioxide (61), cyclizes upon heating in water to give the bicyclic heterocycle (22) in 80% yield. Alternatively, the same product (22) has been obtained by treatment of the 3,5-diamino derivative (60) with tosylazide. With phenyl-diazonium chloride, the diamine (60) gives the diazo compound (63) which, upon oxidation with lead tetraacetate, gives the 2-phenyl derivative (62). Attempts to oxidize the corresponding m-Cl and p-N02 phenyl compounds failed <77JHC427,77MI714-01). 

An example is 2 5 dimethoxy-phenyl diazonium chloride, reacted with sarcosine, (11). These compounds are mixed with the naphthol, printed, and then coupling is brought about either by acidification or by steaming. 

Phenyl diazonium chloride is obtained first hy the diazotization of aniline with nitrous acid as explained earlier, which on coupling with (l-naphthol in the presence of NaOH solution yields the desired coupled product phenyl-azo-P-naphthol. A mole of HCl is eliminated which instantly reacts with NaOH from the medium to produce NaCl and H2O. Importantly, hoth diazotization and coupling reactions are required to he carried out between 0-5°C. 

Method Five, Feofilaktov et al. (275). p-Methoxybenzene + formaldehyde -f- ZnClj + HCl - p-methoxybenzyl chloride (A). (A) + ethyl acetoacetate + sodium ethyl p-methoxybenzylacetoacetate (B). (B) -I- phenyl diazonium chloride p-methoxyphenylp3rruvic acid phenyl-hydrazone -> a-amino-j8-p-methoxyphenylpropionic acid -> tyrosine. An over-all 3rield of 27% was reported. 

---