Diphenylmethyl chloride

Diphenylmethyl chloride (benzhydryl chloride) [90-99-3] M 202.7, m 17.0°, b 167°/17mm, n 1.5960. Dried with Na2S04 and fractionally distd under reduced pressure. 

If (A i[X ]/A 2[Y ]) is not much smaller than unity, then as the substitution reaction proceeds, the increase in [X ] will increase the denominator of Eq. (8-65), slowing the reaction and causing deviation from simple first-order kinetics. This mass-law or common-ion effect is characteristic of an S l process, although, as already seen, it is not a necessary condition. The common-ion effect (also called external return) occurs only with the common ion and must be distinguished from a general kinetic salt effect, which will operate with any ion. An example is provided by the hydrolysis of triphenylmethyl chloride (trityl chloride) the addition of 0.01 M NaCl decreased the rate by fourfold. The solvolysis rate of diphenylmethyl chloride in 80% aqueous acetone was decreased by LiCl but increased by LiBr. ° The 5 2 mechanism will also yield first-order kinetics in a solvolysis reaction, but it should not be susceptible to a common-ion rate inhibition. 

This work was extended to the reaction of diphenylmethyl chloride and... 

Hydrolysis of bis(/j-nitrophenyl) carbonate and /3-chloro-diphenylmethyl chloride... 

FIGURE 2.47. Polarograms obtained for the electrochemical reduction of the diphenyl-methyl radical produced by the reaction of diphenylmethyl chloride by photo-injected electrons in dimethylformamide are shown at two different measurements times (o, 7 ps , 500 pis) in the absence (a) and presence of 8.15 mM methanol (b). Adapted from Figure 1 of reference 50a, with permission from the American Chemical Society. 

The alkylation of phenylacetylene with ferf-butyl chloride, benzyl chloride, and diphenylmethyl chloride follows an AdE2 mechanism57-59 with the involvement of the open vinyl cationic intermediate 17 ... 

The reaction of indazole with trityl chloride yields, together with expected 1- and 2-substituted derivatives, 3-tritylindazole (110) which is unprecedented in indazole chemistry (85BSB421). Benzyl chloride and diphenylmethyl chloride behave classically in this respect (85H(23)2895). 

A quite different heterolytic mechanism has been put forward for the reaction of diphenylmethylene with alcohols to form diphenylmethyl alkyl ethers (Kirmse, 1963). The ability of alcohols to suppress the reaction of the photolytically generated carbene with oxygen increased with increasing acidity of the alcohol. When sodium azide was present, the ylids of diphenylmethyl azide and alkyl ether were close to those obtained by solvolysis of diphenylmethyl chloride under the same conditions. Equation (22) is a plausible formulation of the reaction. 

Relative Reactivity and a Values for Substituted Diphenylmethyl Chlorides ... 

In many reactions the simple saturated nitrogen heterocycles—piperidine, pyrrolidine, piperazine, and morpholine—behave simply as secondary amines that happen to be cyclic. They do the sorts of things that other amines do, acting as nucleophiles in addition and substitution reactions. Morpholine, for example, is acylated by 3,4,5-trimethoxybenzoyl chloride to form the tranquillizer and muscle relaxant trimetozine, and N-methyl piperazine can be alkylated in an S l reaction with diphenylmethyl chloride to give the travel-sickness drug cyclizine. 

The left column of Scheme 35 repeats the ionization-dissociation scheme discussed in Section II.G. If carbon is connected to an electronegative element, one speaks of a covalent compound with a polarized C—X bond. This treatment is justified as there is an approximately tetrahedral environment of the corresponding carbon center. Diphenylmethyl chloride, for example, is never termed a contact ion pair. A well-defined ionization step, which was discussed in Section II.G, generates a carbocation... 

Fio. 1. Arrhenius plot for the hydrolysis of diphenylmethyl chloride in 70% aqueous acetone. (Kohnstam, 1960.)... 

Retardation of solvolysis by common anions, a characteristic feature of Sifl reaction (Ingold, 1953a), was found to be substantial for 4-methoxy-diphenylmethyl chloride (Bailey ef cU., 1966) but could not be detected when the suWrate was the equally reactive chlorodimethyl ether (Hallas and Kohnstam, unpublished work). As the magnitude of this retardation roughly parallels the reactivity of the substrate (see Bailey et al., 1966), these observations are consistent with the view that the chloro-ether does not undergo entirely Sul solvolysis. 

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