Phenyl forms

C HinN204 J20J6-76-5) see Levodopa Af-[5-[l-hydroxy-2-[[2-(4-methoxyphenyl)-l-methylethyl]-(phenylmethyl)amino]ethyI]-2-(phenylmethoxy)phenyl]-form amide... 

The suggestion5 that phenanthridine can probably be alkylated directly under suitably vigorous Friedel-Crafts conditions does not appear to have been tested experimentally. It receives support, however, from the successful conversion of the quaternary salts (220) (R1 = Me, R2 = H) and (220) (R1 = H, R2 = Ph) into the corresponding 221 by heating with polyphosphoric acid.287 Not surprisingly, however, the related salt (220) (R1 = H, R2 = m-methoxy-phenyl) forms 222 under similar conditions.17 Direct alkylation of phenanthridine has been achieved photochemically (see p. 400). 

The tendency of [Co(S2C2R2)2] to dimerize is paralleled by its ability to add additional ligands, those systems with electron-withdrawing substituents (R = CN, CF3, halogenated phenyl) forming... 

Yellow or bluish red oryst. Decomp. at 165 . Sol. PhNOg. Spar. sol. most other org. solvents. Insol. ligO. Odourless and non-volatile. De-oomp. by acids and alkalis. PbOg —> p benzo-qidnone. Zn + AcOH —> 4 4 -dihydro3cydi-phenyl. Forms a quinhydrone with 4 4 -di-hydroxydiphenyl. 

Fragmentation Predominant aromatic fragments of the type ar-O" " and ar-SO" (m/z 125 if ar is phenyl), formed after migration of one of the aryl groups. The ar-S02 ion is unimportant ar+ is intense. Small fragments due to SO2, SO2H, and SO2H2 eliminations (Am 64, 65, and 66, respectively). With alkyl substituents in ortho position, [M-OH]" " and [M-H20]" " are formed, upon which SO elimination follows. 

Occurs in coal tar, in various plants and in faeces, being formed by the action of the intestinal bacteria on tryptophan. It can be prepared by the action of acid on the phenyl-hydrazone of pyruvic acid to give indole-2-carboxylate which can be decarboxylated to indole. 

Fig. 1. The rate-determining step in the neutral hydrolysis of paramethoxy-phenyl dichloroacetate. In the reactant state (a) a water molecule is in proximity of the carbonyl carbon after concerted proton transfer to a second water molecule and electron redistribution, a tetrahedral intermediate (b) is formed.

As an example, the empirical formula of phenylalanine may be split into a more extended form that shows the presence of a phenyl ring, as well as an amino and a carboxylic acid group (the condensed form in Figure 2-4). 

Example Anoth er example of Iron tier orbital theory uses the reaction ol phenyl-butadiene with ph en ylethylene. This reaction is a [4-1-21 pericyclic addition to form a six-membered ring. It could proceed with the two phenyl rings close to each other (head to head) or further away front each other (head to tail). 

Place the distillate in a separating-funnel and extract the benzonitrile twice, using about 30 ml. of ether for each extraction. Return the united ethereal extracts to the funnel and shake with 10% sodium hydroxide solution to eliminate traces of phenol formed by decomposition of the benzenediazonium chloride. Then run off the lower aqueous layer, and shake the ethereal solution with about an equal volume of dilute sulphuric acid to remove traces of foul-smelling phenyl isocyanide (CaHjNC) which are always present. Finally separate the sulphuric acid as completely as possible, and shake the ether with water to ensure absence of acid. Run off the water and dry the benzonitrile solution over granular calcium chloride for about 20 minutes. 

Aminoazobenzene is a very weak base, and consequently it will not form salts with weak organic acids, such as acetic acid, although it will do so with the strong mineral acids, such as hydrochloric acid. Aminoazobenzene is a yellowish-brown compound, whilst the hydrochloride is steel blue. The colour of the latter is presumably due to the addition of the proton to the phenyl-N-atom, the cation thus having benzenoid and quinonoid forms ... 

Acetophenone similarly gives an oxime, CHjCCgHjlCtNOH, of m.p. 59° owing to its lower m.p. and its greater solubility in most liquids, it is not as suitable as the phenylhydrazone for characterising the ketone. Its chief use is for the preparation of 1-phenyl-ethylamine, CHjCCgHslCHNHj, which can be readily obtained by the reduction of the oxime or by the Leuckart reaction (p. 223), and which can then be resolved by d-tartaric acid and /-malic acid into optically active forms. The optically active amine is frequently used in turn for the resolution of racemic acids. 

If ethyl acetoacetate is warmed with an equivalent quantity of phenyl hydrazine, the corresponding phenylhydrazone (A) is readily formed. On... 

The tautomerism shown by the pyrazolones is of considerable interest. Thus the above methyl"-phenyl pyrazolone when fused or in solution can exist in the tautomeric forms (C), (D), and (E). 

When the methyl-phenyl-pyrazolone is heated with methyl iodide in methano-lie solution, it acts in the form (D), the — NH— group undergoing methy lation, with the formation of the hydriodide of 2,3-dimethyl- l-phenyl-5 Pyrazolone, or antipyrine (F), a drug used (either as the free base or as the... 

The Reformatsky Reaction consists of the interaction of an ester of an a-halogeno-acid with an aldehyde, a ketone or another ester in the presence of zinc. For example, if a mixture of ethyl bromoacetate and benzaldehyde is heated with zinc, the latter undoubtedly first combines with the ethyl bromoacetate to form a Grignard-like reagent (reaction A), which then adds on to the benzaldehyde Just as a Grignard reagent would do (reaction B). The complex so formed, on acidification gives ethyl p-phenyl-p-hydroxy-propionate (reaction C). Note that reaction A could not satisfactorily be carried out using... 

This rapid formation of the crystalline quinoxaline derivative can therefore be used to identify 1,2-diketones conversely, a nuclear-substituted o-phenyl-enediamine can be identified by the quinoxaline derivative which it forms with a known 1,2-diketone such as benzil. 

It is convenient to describe here certain polyvalent iodine compounds, formed by such substances as iodobenzene and p-iodotoluene. lodobenzeue in chloroform solution reacts readily with chlorine to form iodobenzene dlchlorlde (phenyl iododichloride) (I) ... 

The initial product, nitrosobenzene, is so easily reduced to p-phenylhydroxyl-amine that it has never been isolated in the free state, but its presence has been established by reaction in solution with hydroxylamine to 3deld a phenyldi-azonium salt, which couples readily with a a-naphthylamine to form the dyestuff phenyl-azo-a-naphthylamine (compare Section IV,77) ... 

Pheiiyl iso-thiocyanate may be prepared in quantity directly from aniline. Aniline, carbon disulphide and concentrated aqueous ammonia react to form the sparingly soluble ammonium phenyldithiocarbamate this is decomposed by lead nitrate to produce phenyl iso-thiocyanate ... 

The ester and catalj st are usually employed in equimoleciilar amounts. With R =CjHs (phenyl propionate), the products are o- and p-propiophenol with R = CH3 (phenyl acetate), o- and p-hydroxyacetophenone are formed. The nature of the product is influenced by the structure of the ester, by the temperature, the solvent and the amount of aluminium chloride used generally, low reaction temperatures favour the formation of p-hydroxy ketones. It is usually possible to separate the two hydroxy ketones by fractional distillation under diminished pressure through an efficient fractionating column or by steam distillation the ortho compounds, being chelated, are more volatile in steam It may be mentioned that Clemmensen reduction (compare Section IV,6) of the hj droxy ketones affords an excellent route to the substituted phenols. 

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 ... 

The formation of alkylbenzenes, largely free from unaaturated compounds, provides another interesting application of organosodium compounds. Thus pure M-butylbenzene is readily obtained in good yield from benzyl sodium and n-propyl bromide. Benzyl-sodium is conveniently prepared by first forming phenyl-sodium by reaction between sodium and chlorobenzene in a toluene medium, followed by heating the toluene suspension of the phenyl-sodium at 105° for about 35 minutes ... 

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