Ortho compound

Acetanilide also undergoes ready bromination, with the formation of a mixture of o- and /(-bromoacetanilidc. The ortho compound is formed in only... 

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. 

The corresponding diazo component with a 6-nitro substituent gives Eriochrome Black T /7787-61-7] (18b, R = NO2) (Cl Mordant Black 11 Cl 14645) which is supposed to consist almost exclusively of the ortho compound. 

A plot of log (kiku) against pKa (this is called a Br nsted-type plot, as we will see in Section 7.4) for meta- and para-substituted pyridines gave an LFER describing normal behavior. On this same plot the or// o-substituted pyridines all fell below the m and p reference line. The steric constant was defined as the vertical distance between the reference line [whose equation was log (k plkn) = 0.35 pK — 1.73] and the result for the ortho compound, or... 

He suggested a nomenclature for the terpenes by which those compounds which contain a double linkage between the nucleus and the side chain should be called pseudo-compounds, whilst the compounds with the double linkage in the nucleus should be the ortho-compounds. He suggested the following formulae —... 

Ortho-verbindung,/. ortho compound, -xylol, n. orthoxylene, o-xylene. -zimtsdure, /. orthocinnamic acid. 

Commercial c-chloronitrobenzene containing 95-98 per cent of the ortho compound was used. 

For ortho, meta, and para diphenylbenzene we consider eight unexcited structures of the type indicated by the letter A in Fig. 5, thirty-six first-excited structures of type B, and thirty-six of type C, in which there is conjugation with the central ring. This includes all first-excited structures for m-diphenylbenzene. For ortho and para diphenylbenzene, however, there are in addition nine first-excited structures of type D, in which the two end rings are conjugated together. The secular equation for the ortho compound is... 

Periodic acid also oxidises phenols, particularly the ortho compounds. Thus catechol gives o. benzyoquione on oxidation with sodium periodate. 

Aside from differences in intensities, the three isomers give very similar spectra. The meta and para compounds give a small peak at m/z 122 from loss of an O atom, whereas the ortho compound eliminates OH as follows to give a small peak at m/z 121. 

By comparison with the heal of dimerization of p-hydroxybenzoie acid in the same solvent (benzene) an indirect estimate of the mternal bonding in the ortho-compound was made on the assumpth.-o that the difference between the isomers arises from the energy needed io disrupt the internal bond in the ortho-compound when the dimer is formed. 

Mercuration at lower temperatures than that recommended gives a poorer yield of the ortho compound. 

Tolunitrile can be prepared in exactly the same manner from />-toluidine the product, which distils at 104-106°/20 mm., solidifies in the receiver to a mass of nearly colorless needles which melt at 25-27°. The yield is the same as with the ortho compound (Note 7). 

Fluorine NMR data for the three bis-(trifluoromethyl)benzenes are given in Scheme 5.51, while such data for the tris(trifluoromethyl)-, tetrakis(trifluoromethyl)-, pentakis(trifluoromethyl)-, and hexakis (trifluoromethyl)benzenes are given in Scheme 5.52.3 In the bis(trifluoromethyl)benzene series, one will notice that adding a second trifluoromethyl group meta or para does not have much effect upon the fluorine chemical shifts, but when vicinal, as in the ortho compound, considerable deshielding is observed. 

After completing the nitration by warming on the water-bath for twenty miuutes, the mixture is poured into water, and the mixed o- and p-nitro-esters separated by digestion with a little alcohol, in which only the ortho-compound dissolves. The substance may then be obtained in a pure state by pouring the alcoholic solution into cold water and filtering. 

The reaction gives a mixture of the ortho- 53 and para- 54 products. The ortho -compound is converted into saccharine by reaction with ammonia and oxidation and the para-compound toluene-p-sulfonyl chloride 54, or tosyl chloride, is sold as a reagent for converting alcohols into leaving groups. 

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