915107-30-1

Methyl 6-Chloro-5-hydroxynicotinate is a useful synthetic intermediate in the synthesis of 5-Hydroxy-Imidacloprid (H943220); a metabolite of Imidacloprid (I274990) which is an active ingredient in certain neuro-active insecticides.

The structure of 6-Chloro-5-hydroxy-nicotinic acid methyl ester contains chlorine, hydroxyl and ester functional groups at the same time, and has high reactivity. It can be used to construct pyridine heterocyclic skeletons and then develop new anti-inflammatory, antibacterial or nervous system active drugs.

The general procedure for the synthesis of 6-chloro-5-hydroxynicotinic acid methyl ester from 5-hydroxynicotinic acid was as follows: aqueous sodium hypochlorite (6.15%, 26.7 mL, 22 mmol) was added slowly and dropwise to a flask containing 5-hydroxynicotinic acid methyl ester (4.5 g, 29 mmol) under ice bath cooling conditions. The reaction mixture was stirred for 30 min and then 2 M hydrochloric acid (20 mL) was added to terminate the reaction. The white crystals produced in the reaction were collected by filtration to give 2.31 g of methyl 6-chloro-5-hydroxynicotinate in 42% yield. The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3) and LC-MS: 1H NMR δ 10.32 (bs, 1H), 8.48 (d, 1H), 7.84 (d, 1H), 7.40 (s, 1H), 3.93 (s, 3H); LC-MS (ELSD) showed a calculated mass of C7H6ClNO3 [M]+ was 187 and the measured value was 187.

[1] Patent: US2008/108667, 2008, A1. Location in patent: Page/Page column 9-10
[2] Patent: US2016/376283, 2016, A1. Location in patent: Paragraph 0493; 0494
[3] Patent: WO2011/48525, 2011, A1. Location in patent: Page/Page column 43
[4] Patent: US2009/131468, 2009, A1. Location in patent: Page/Page column 65
[5] Patent: WO2009/64251, 2009, A1. Location in patent: Page/Page column 137