4-Amino-2-chlorobenzoic acid → 2-Chloro-4-hydrazinylbenzoic acid hydrochloride

Temperature

0 °C

To a suspension of 4-amino-2-chlorobenzoic acid (3.00 g, 17.5 mmol) in hydrochloric acid (1.0 M, 30 mL) at 0° C. was added a solution of sodium nitrite (1.24 g, 18.0 mmol) in water (5.0 mL) over 5 min and the reaction mixture maintained at 0° C. for 5 hr. The resulting mixture was treated with tin(II) chloride (9.28 g, 49.0 mmol) in hydrochloric acid (1.0 M, 60 mL) and was warmed to RT for 64 hr. The resulting thick precipitate which formed was isolated by filtration, washed with ethanol (16 mL) and ether (15 mL) and was dried in vacuo to afford 2-chloro-4-hydrazinylbenzoic acid hydrochloride as a beige solid (3.54 g, 90% purity, 82%); Rt 0.22 min (Method 2); m/z 187 (M+H)+, (ES+). This material was used in the subsequent step without further purification.

1. temperaturewas warmed to RT for 64 hr
2. customThe resulting thick precipitate which formed
3. customwas isolated by filtration
4. washwashed with ethanol (16 mL) and ether (15 mL)
5. customwas dried in vacuo

ORD record

ord-67511a9f4fad46489f9dfbfaf9f6c508

Source dataset

uspto-grants-2015_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09024041B2