Yield: 95%

Reaction Conditions:

with sulfuryl dichloride;acetic acid at 10 - 54; for 4.5 h;Concentration;Reagent/catalyst;

Steps:

1 Preparation of S1: 3-cyano-4-methoxy-5-chloro 2- (1H) pyridone
3-cyano-4-methoxy-2-H-pyridone (6.0 g, 0.04 mol)45ml glacial acetic acid into 250 ml three-necked flask,Cooling to below 15 ,Then 6.18 g (0.045 mol) g of sulfonyl chloride was added dropwise,Solution temperature control between 10 ~ 15 ,The rate of dropping can be controlled according to the temperature change.After dripping,Stirring for half an hour,Heating up to 52 ± 2 ,Insulation 50-54 reaction 4h,TLC (TLC developing agent: ethyl acetate: methanol = 9: 1) monitoring the reaction of raw materials is completed,The reaction solution was cooled to 20 ± 2 ° C,Stir for 2 hours,filter,The filter cake was washed with 58 ml of water,The wet product was dried at 80 ° C under normal pressure for 12 hours to dry,To give 7.01 g of 3-cyano-4-methoxy-5-chloro 2- (1H) pyridone as a white powder,Yield 95.0%Theoretical yield 7.38g.

References:

Jinan Chuan Cheng Pharmaceutical R&D Co., Ltd.;Liu, Huaizhen;Ma, Juliang;Guan, Chengtai CN106316934, 2017, A Location in patent:Paragraph 0022; 0023; 0025; 0027; 0028