The reactivity of
1-halogeno-2,6-dinitrobenzenes with methanolic methoxide has been studied
quantitatively and compared with the results of similar studies of o- and p-halogenonitrobenzenes and 1-halogeno- 2,4-dinitrobenzenes.
Adverse steric interactions of the ortho-nitro group are very small in the
o-halogenonitro- and 1-halogeno-2,4- dinitrobenzenes. The interactions are
substantially larger in the reactions of 1-halogeno-2,6-dinitrobenzenes in
displacement of Cl, Br, and I, but not of F, but they
are small compared to steric interactions found in many other classes of
reactions. ��� Steric effects are observed as a reduction
in rates affecting values of the Substituent Rate Factors of the o-nitro group,
and affecting also the mobility as a leaving group of Cl,
Br, and I, but not of F. However, since Cl is the
usual reference standard for leaving group mobility, that of F appears as
having an unusually high value. Nevertheless a depression of the mobility of
iodine from its typical range is also evident.