ISSN:
0894-3230
Keywords:
Organic Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The substitution reactions of Br(CH2)nBr(1, n = 3-5) with KCN in methanol were studied in detail. Second-order rate constants k1 [formation of the mononitrile (2) from 1] and k2 (formation of the dinitrile (3) from 2) were determined, as were the rates for the reaction of H(CH2)nBr (4, n = 3-5) with KCN under the same conditions. The ratios k2/k1 ( = x) of the three homologs of 1 were found to be 1.15, 0.77 and 0.61 for n = 3, 4 and 5, respectively; a x value of 0.5 indicates that the functional groups behave independently. The second-order rate constants k1 (statistically corrected) and k2 exhibit modest enhancements compared with model compound 4 when any of the following substituents are present: δ or ∊-bromo, γ-, δ-, or ∊-cyano. By contrast, a γ-bromo substituent slightly retards the rate. These results indicate that the functional groups do influence each other to a modest degree by field effects which accelerate the reactions. Steric effects do not appear to play a significant role.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/poc.610050608
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