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The first preparation of the title compound (3) is reported and its reactivity with nucleophiles examined. Attack occurs at both the benzotriazole and the picryl ring moieties, the former process giving rise to spectrally observable Meisenheimer type σ-complexes, the latter to displacement. The results allow comparison to be drawn with the behaviour of 4,6-dinitrobenzofuroxan, which also acts as a super-electrophile. The structure of (3) has been determined from three-dimensional X-ray data collected from a single crystal. The material crystallized in space group Pbca of the orthorhombic system with eight molecules in a cell of dimensions a 16.050, b 11.478, c 17.823 A; V 3283.5 �3.

Saponification of 7 gave 2-ethylidene-3-methylglutaric acid as needles from benzene-hexane, mp 129-130°(lit.16 mp 129°).

A comparative study has been made of the rates of hydrolysis of the 2,4-and 2,6-dichloro-and 2,4and 2,6-dicarbomethoxy derivatives of benzyl bromide, the l-(2,4-and 2,6-dichlorophenyl)ethyl bromides, and the l-(2,4-and 2,6-dicarbomethoxyphenyl)ethyl bromides in 80 vol % aqueous dioxane. The four disubstituted benzyl bromides react at comparable rates. At 70.7°the 2,4-dichloro derivative of 1-phenylethyl bromide is about one-half as reactive as its 2,4-dicarbomethoxy analog, but l-(2,6-dichlorophenyl)ethyl bromide is only V120 as reactive as its 2,6-dicarbomethoxy analog. On the basis of an analysis of the electronic and steric influences of the ring substituents (Cl and COOCHs) on the reactivities of these organic bromides, the high solvolysis rate of l-(2,6-dicarbomethoxyphenyl)ethyl bromide is attributed to a geometric situation which forces intramolecular nucleophilic participation of the carbomethoxy groups in the displacement process.

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