Sodium Hydroxide → 5-Chloro-2-(trifluoromethyl)pyridine

Participants

Reaction Steps

19.91 g of 2-hydrazino-3-chloro-6-trifluoromethyl pyridine from the small batch and 30.19 g from the large batch were combined (50.10 g total, 0.237 mol) in a 2 L, three-neck flask with a mechanical stirrer and an addition funnel. Dichloromethane (190 g) and sodium hydroxide (237 g, 1N solution) were added to the flask. Sodium hypochlorite (NaOCl) (354 g, 0.238 mol, 5% solution) was charged to the addition funnel. The sodium hypochlorite solution was added over 1 hour as the solution turned yellow, then orange, and then purple-brown. The conversion was approximately 36% at the end of the sodium hypochlorite addition. The solution was stirred for an additional 6.5 hours, at which point the conversion was about 98%. Agitation was stopped and the solution was left overnight. The next morning, sodium hypochlorite (9 g, 0.006 mol, 5% solution) was added, and the solution was stirred for 1.5 hours, at which point sampling indicated that there was less than 1% starting material. The layers were separated and the aqueous layer was extracted twice with dichloromethane (100 mL). The organic layers were combined, washed with water, dried with magnesium sulfate, filtered, and concentrated on the rotovap to give 46.44 g of crude 3-chloro-6-trifluoromethyl pyridine.

Provenance & Evidence