Methoxy-dechlorination

Added in proof. To emphasize the comparisons with naphthalene, the reaction center of each series studied has been called the 1-position. For example, in the methoxy-dechlorination of substituted 4-chloroquinolines the position to which the chlorine atom is attached is the 1-position and the nitrogen atom is the 4-position this is in contrast to conventional numbering, where the nitrogen atom is always 1. 

Relative Rates for the Methoxy-Dechlorination of 2-ChLOROQUINOXALINES AND 4-ChLOROCINNOLINES AT 5° ... 

Fig. 2, Correlation of reactivity data (log A ) for the methoxy-dechlorination of substituted 2-chloroquinolmes and 2-chloroquinoxalines.

Fig. 6. The Hammett plot for the methoxy-dechlorination of meto-substituted 2-chloroquinolines.

At present, the most probable value of the reaction constant for the methoxy-dechlorination of 4-chloroquinolines is obtained from Eq. 

The ease of reaction of halopyridazines is indicated by the exothermic nature of the reaction of 3,6-dichloropyridazine with sodium methoxide at room temperature to yield 3-chloro-6-methoxy-pyridazine. Displacement of the deactivated chloro group in the latter required heating (66°, < 8 hr) the reaction mixture. Competitive methoxy-dechlorination (20°, 12 hr) of 3,4,6-trichloropyridazine shows the superior reactivity of the 4-position the 3,6-dichloro-4-methoxy analog (296) was isolated in high yield. The greater reactivity of the... 

When a hydrogen atom is peri to an azine-nitrogen, there is no steric inhibition of resonance activation as there is in 1-nitronaph-thalene (4-methoxy-dechlorination of its 4-chloro derivative seems to be thereby decelerated only 2-fold in rate). Steric hindrance of nucleophihc substitution by the co-planar peri hydrogen is sometimes... 

Irregular kinetics were observed in methoxy-dechlorination of 1-chloro-2,4,5-tiinitronaphthalene. This observation was shown to arise from reaction of the 1-methoxy product with more methoxide ion to form the intermediate complex 389 comparable to that formed... 

Illuminati and co-workers have recently reported additional data on the effects of benzo-ring substituents on the rate of methoxy-dechlorination of quinolines, quinoxalines, and cinnolines the accelerations and decelerations reflect the decreases and increases in activation energy. Both 6- and 7-chloro groups increase the rate (by 6- and... 

This approach is confirmed by good correlations of the methoxy-dechlorination rates for 6-substituted 3-chloropyridazines (series 63, Z = Cl)... 

---