Hydrochloric Acid → 2-Hydroxy-4-(hydroxyimino)-2-[(1H-indol-3-yl)methyl]pentanedioic acid

Temperatur

35 °C

Indole-3-pyruvic acid (73.8 g, 352 mmol) was added to and dissolved in 917 g of an aqueous solution of 1.6 wt % sodium hydroxide. The temperature of the reaction mixture was maintained at 35° C. As the pH value was maintained at 1.1 using an aqueous solution of 30% sodium hydroxide, 310.2 g (1761 mmol) of an aqueous solution of 50% pyruvic acid was dripped over 2 hours. The reaction was further continued for 4.5 hours to yield a reaction mixture containing 4-hydroxy-4-(3-indolylmethyl)-2-ketoglutaric acid. As the pH value was maintained at 7 with the addition of the aqueous solution of 30% sodium hydroxide, 367.2 g (2114 mmol) of an aqueous solution of 40% hydroxylamine hydrochloride was added thereto, and stirred at 5° C. for 17.5 hours. The pH value of the reaction mixture was adjusted to 2 using concentrated hydrochloric acid, and organic matters were extracted with ethyl acetate. The organic layer was washed with saturated aqueous NaCl solution, and concentrated to yield residue. The residue was recrystallized from 60 mL of 28% aqueous ammonia and 350 mL of 2-propanol to yield 43.4 g of diammonium salt of 4-hydroxy-4-(3-indolylmethyl)-2-hydroxyiminoglutaric acid (142 mmol, yield 40% versus indole-3-pyruvic acid) as crystal.

1. waitThe reaction was further continued for 4.5 hours
2. customto yield a reaction mixture
3. additionwas added
4. extractionwere extracted with ethyl acetate
5. washThe organic layer was washed with saturated aqueous NaCl solution
6. concentrationconcentrated
7. customto yield residue
8. customThe residue was recrystallized from 60 mL of 28% aqueous ammonia and 350 mL of 2-propanol

ORD-Eintrag

ord-3780d150f2c040479b8dca37b827cb17

Quelldatensatz

uspto-grants-2008_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07354746B1