Synthesis
Preparation of 5-methyl-3-pyridinemethanol: mix magnesium chloride, potassium borohydride and tetrahydrofuran according to the molar ratio of 2:2:1, raise the temperature to 67°C, reflux for 2 h, and then cool to room temperature to obtain solution B. Dissolve methyl 5-methylnicotinate prepared in step S1 in tetrahydrofuran, adjust the temperature to 40°C, and slowly dropwise add the solution B, and control the dropwise addition time to be completed in 1.3 hours. After the dropwise addition was completed, the reaction was continued at 40 °C for 1 hour with continuous stirring during the period. Upon completion of the reaction, it was cooled to room temperature to obtain Solution C. Methanol was added to Solution C to quench the reaction, followed by raising the temperature to 40 °C and removing the tetrahydrofuran and methanol by rotary evaporation to obtain Concentrate D. To Concentrate D, water was added and the extract was carried out with ethyl acetate for a total of three extractions. The ethyl acetate phases were combined and dried by adding anhydrous sodium sulfate to a moisture content of 0.3 wt%, filtered, and the ethyl acetate phase was taken for rotary evaporation to give the final 5-methyl-3-pyridine methanol.
References
[1] Journal of Medicinal Chemistry, 2004, vol. 47, # 25, p. 6299 - 6310
[2] Synthetic Communications, 2008, vol. 38, # 1, p. 122 - 127
[3] Patent: WO2012/97196, 2012, A1. Location in patent: Page/Page column 34
[4] Patent: EP2824103, 2015, A1. Location in patent: Paragraph 0040
[5] Patent: CN106560471, 2017, A. Location in patent: Paragraph 0055; 0061; 0067; 0073; 0079; 0085; 0091; 0096
