Hydrochloric Acid → 2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetic acid

Temperature

0 °C

To a suspension of methyl 2-methoxyimino-2-(5-formamido-1,2,4-thiadiazole-3-yl)-acetate (syn-isomer) (146 g, 0.60 mmol) in water (720 g) was cooled to an internal temperature of 0° C. and then 10% aqueous sodium hydroxide solution (720 ml) was added dropwise thereto. The mixture was allowed to react at a temperature in the range of 0°±1° C. for 1 hr., then heated to an internal temperature of 45° to 50° C. to react for 2 hrs. The reaction mixture was then neutralized with concentrated hydrochloric acid (62.4 g) to pH 6.5 to 7.5., and concentrated at an internal temperature of below 60° C. and then adjusted to pH 3 with concentrated hydrochloric acid (62 g). After that, it was decolorized and purified with activated carbon (14.6 g), followed by the addition of concentrated hydrochloric acid (62.4 g). It was then cooled to separate crystals which were collected by filtration and dried to give 2-methoxyimino-2-(5-amino-1,2,4-thiadiazole-3-yl) acetic acid (syn-isomer) (166.7 g, yield: 88.0%, and purity by HPLC: 99.4%).

1. customto react at a temperature in the range of 0°±1° C. for 1 hr
2. temperature, then heated to an internal temperature of 45° to 50° C.
3. customto react for 2 hrs
4. concentration, and concentrated at an internal temperature of below 60° C.
5. custompurified with activated carbon (14.6 g)
6. additionfollowed by the addition of concentrated hydrochloric acid (62.4 g)
7. temperatureIt was then cooled
8. customto separate crystals which
9. filtrationwere collected by filtration
10. customdried

ORD record

ord-ae615ff75250460e9e2aed0d1b34f336

Source dataset

uspto-grants-1998_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05773624