Benzyl bromide, pyrolysis

Benzyl radical, C6H5CH2, and its deuterated analogues (C6H5CD2, CfiDsCHz) were obtained by vacuum thermolysis of dibenzyl derivatives or by pyrolysis of the corresponding benzyl bromides (17) (Baskir, 1989). 

Vinyl chlorides The anion can be alkylated by alkyl iodides (HMPT) or benzylic bromides in high yield. On pyrolysis at 160°, the products are converted into vinyl chlorides (cis- and trans-isomers). 

Conformational analysis " of 3j8-ethoxycarbonyl-3o -phenyltropane, an analogue of pethidine, by n.m.r. spectroscopy, indicated axial preference of the 3a-phenyl group, hence a chair conformation for the piperidine ring (22). However, the intermediates 3a-diphenylhydroxymethyl-3/3-tropanol (23) and 3a-phenyl-3)8-tropanylphenyl ketone (24) favour the boat form. Pyrolysis of (22) led, with the boat form in the transition state, to 7-aza-3-chloro-7-methyl-l-phenyl-8-oxobicyclo[4,2,l]nonane (25), based on elemental analysis and mass spectrum. ( —)-1-p-Butoxyphenyl [a- H]hyoscyaminium bromide was prepared from ( —)-hyoscyamine and p-butoxy[a- H]benzyl bromide. N-Methyl [l- H]- psicaine neu and U-tritiated psicaine have also been described." ... 

Preparation.—From Amines or Alcohols. Katritzky has reviewed mechanistic and preparative aspects of the conversion of primary amino to other functional groups mediated by pyrilium cations according to the general Scheme 34, where nucleophiles include the halide anions (cf. 4,157) and carboxylates (c/. 4,138), Other recent publications in this area have included full details of the preparation of primary alkyl and benzyl fluorides by this route using 2,4,6-triphenylpyrilium salts (4,157). The conversion of primary amines to the corresponding bromides has now been improved, either by a modified pyrolysis procedure but still... 

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