(6β)-3-(1-Methyl-1H-tetrazole-5-ylthiomethyl)-7α-amino-7-methoxy-8-oxo-5-oxa-1-azabicyclo[4.2.0]octa-2-ene-2-carboxylic acid benzhydryl ester synthesis

Yield: 93.2%

Reaction Conditions:

with pyridine;bis(trichloromethyl) carbonate in dichloromethane at -25 - 5; for 3 h;Inert atmosphere;Reagent/catalyst;Temperature;Solvent;

Steps:

2 preparation of 7β-amino-7α-methoxy-3-(1-methyl-1H-tetrazol-5-ylthiomethyl)-1-oxa-3-cephem-4-carboxylic acid diphenylmethyl ester
In with mechanical agitation, thermometer of the 1000 ml three-mouth bottle, by adding 400 ml dichloromethane, input compound (1a) 30.7g (0.05mol) (R ₁ = phenyl, R ₂ = 1-methyl -1H-tetrazole-5-sulfur methylene R ₃ =-CH (C ₆ H ₅) ₂, X=O), adding pyridine 15.8g (0.2mol), stirring to dissolve, nitrogen protection, low temperature bath for cooling to -25 °C, batch adding double (trichloromethyl) carbonate 19.8g (0.0667mol), control temperature not higher than -10 °C, 0 . 5-1 hour, with 1 hour the temperature slowly 5 °C reaction 2 hours; the response finishes, low temperature bath for cooling to -25 °C, 15 minutes add methanol the dripping 32g (1mol), continue to in -20 - - 10 °C reaction under 1 hour; raising the temperature to -5 °C, adds by drops full and sodium bicarbonate solution to the pH value = 7-8 ; separating the organic layer, dichloromethane is used for the water 100 ml × 2 extraction two times, evaporation to dryness under reduced pressure to obtain solid, with acetone 100 ml eluviation, to obtain the target product (3a), drying, weight 23.7g, content 99.7%, yield of 93.2%

References:

Zhejiang XinHeCheng Pharmaceutical Co Ltd;Zhejiang University;Zhang, YuHong;Liu, luping;Qian, HongSheng;Lu, guobin;Tang, zeben CN103183686, 2016, B Location in patent:Paragraph 0045; 0046