5-Fluoroisatin → 5-fluoro-1,3-dihydro-2H-indol-2-one

Temperature

110 °C

A solution of 5-Fluoroisatin (1 g) in Hydrazine hydrate (55%, 10 ml) was heated at 110° C. for 30 minutes. Once the suspension has gone into solution, the reaction was heated at 110° C. for 4 hours, then cooled at 0° C. The precipitate was filtered and washed with water. The solid was suspended in water (10 ml), the pH was lowered to pH2 by addition of HCl conc, and the solution stirred at room temperature for 5 hours. The precipitate was collected, the solid washed with water (2×15 ml) and dried in the vacuum oven at 40° C. (0.26 g, 30%). 1H NMR (400 MHz, DMSO-d6) δ 10.2 (s, 1H); 6.8-7.0 (dd, 2H); 6.6 (m, 1H); 3.2 (s, 2H); LCMS: method D, RT=1.736 min, [MH+=152].

1. temperaturecooled at 0° C
2. filtrationThe precipitate was filtered
3. washwashed with water
4. additionthe pH was lowered to pH2 by addition of HCl conc
5. customThe precipitate was collected
6. washthe solid washed with water (2×15 ml)
7. customdried in the vacuum oven at 40° C. (0.26 g, 30%)

ORD record

ord-fc31edc234fc4dd7b1b6b4733c4d33ac

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08163511B2