4- Cyanobenzyl chloride

FIGURE 3.26. Potential energy profiles (from B3LYP/6-31G calculations) for the cleavage of 4-cyanobenzyl chloride (a) 3- and 4-cyanobenzyl bromides (b and c) anion radicals in the gas phase (top) and in a solvent (middle and bottom) (from COSMO solvation calculations with a dielectric constant of 36.6 and 78.4, respectively). Dotted and solid lines best-fitting Morse and dissociative Morse curves, respectively. Adapted from Figures 4 and 5 of reference 43, with permission from the American Chemical Society. 

For the synthesis of 4, 2-cyanobenzyl chloride is first treated with triethyl phosphite to give 2- cyano-(l-diethylphosphonomethyl)benzene [23973-65-1], which reacts with terephthalaldehyde in the presence of sodium methoxide to yield l,4-bis(2-cyanostyiyl)benzene (4) [13001-39-3] [28]... 

The cyano group is another group that clearly facilitates substitution reactions via initial ET, although not as effectively as a nitro group96. Thus, / -cyanobenzyl chloride gives... 

Halogen atoms in the alpha position to an aromatic nucleus (benzyl-type) are very readily hydrolyzed. With proper precautions hydrolysis of the halogen atom of -cyanobenzyl chloride is possible without affecting the cyanide group -cyanobenzyl alcohol is obtained in 85% yield. ... 

Diethyl 2-, 3-, and 4-cyanobcnzylphosphonates are generally obtained in high yields by the Michaelis-Arbuzov reaction of triclhyl phosphite with the corresponding cyanobenzyl chloride or bromide.- 5 Diethyl 3-(9-cyano-9-lluorenyl)propylphosphonate is analogously obtained in 75% yield from triethyl phosphite and the corresponding bromide. 

Dimethyl 2-cyanobenzylphosphonate is prepared by treahnent of a solution of 2-cyanobenzyl chloride and dimethyl phosphite with MeONa in boiling ( ,11, to give a yield (58%) comparable with those obtained by the Michaelis-Arbuzov reaction (Scheme 6.32).- ... 

Reaction of o-cyanobenzyl chloride with amines gives l-aminoi oindoles (Equation (8)) <71UKZ916>. 

II, 2.4]-triazin-3(2/y)-one (151, R = Me, R = H) (70JHCI23I). Similarly, 150 (R = Me) reacts with a-cyanobenzyl p-toluene sulfonate lPhCH(CN)OTS] or a-cyanobenzyl bromide PhCH(CN)Br] to afford 151 (R = Me, R = Ph) (7IJHC62I). Structure 151 was proved by its reduction with diborane to 152, which was also obtained by an independent synthesis involving the reaction of 153 with thionyl chloride followed by base-catalyzed cyclization (70JHCI231 71JHC621). To ascertain whether the methyl group at the I-position in 150 (R = Me) influences the direction of cyclization, the thione 150 (R = H) was allowed to condense with a-cyanobenzyl-p-toluene sulfonate and ethyl a-bromophenylacetate. In both cases 151 (R = H, R = Ph) was obtained. Compound 150, however, on reaction with 1,2-dibromoethane, furnished another bicyclic system (154). The difference in the behavior of 150 toward dibromoethane and other reagents such as ethyl bromoacetate and a-cyanobenzyl p-toluene... 

Similar reactions occur when /Y-acetonylpyridinium chloride, AL(l-cyanobenzyl)pyridinium benzenesulfonate (12), and related compounds, are used as the two-carbon unit. This reaction is exemplified by the synthesis of 2,6-diphenylpteridine-4,7-diamine 5-oxide (13).51... 

Quench the reaction mixture by pouring into a saturated ammonium chloride solution (20 ml). Extract the aqueous layer with diethyl ether (3 X 20 ml), then dry the combined organic layers over MgS04, filter, and concentrate under reduced pressure. Isolate the product from the crude reaction mixture by flash chromatography (ethyl acetate hexanes, 1 5, v/v) 2,3-di(/ -cyanobenzyl)-l,3-butadiene is obtained in 93% yield. 

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