Stannous Chloride → Ethyl (4-hydrazinophenyl)acetate hydrochloride

Temperature

0 °C

A solution of sodium nitrite (NaNO2, 4.04 g, 58.6 mmol) in H2O (20 mL) was added to a cooled (−5° C., ice-salt) solution of ethyl 4-aminophenylacetate (10 g, 55.8 mmol) in conc. HCl (55 mL), at a rate such that the temperature did not exceed 0° C. The mixture was stirred at 0° C. for 10 min and then added portion-wise to a cooled (−5° C., ice-salt) and rapidly-stirred solution of tin(II) chloride (SnCl2, 39.67 g, 209.2 mmol) in conc. HCl (30 mL), at a rate such that the temperature did not exceed 0° C. The resulting cream-colored suspension was warmed to 25° C. and stirred at room temperature for 2-3 hrs and then was filtered under vacuum. The collected solid was washed with water and ether and then air dried to afford the desired product as a pale solid (HCl salt). Precipitate that formed in the filtrates upon standing for 16 h was collected by filtration, washed with water and ether, and air-dried. The combined solids were obtained in 88% yield (11.28 g). 1H-NMR (DMSO-d6) δ 8.85 (broad, 2H), 7.73 (broad, 1H), 7.10 (d, J=8.4 Hz, 2H), 6.82 (d, J=8.4 Hz, 2H), 4.03 (q, J=7.0 Hz, 2H), 3.53 (s, 2H), 1.16 (t, J=7.1 Hz, 3H); MS LC-MS [M+H]+=195.0, RT=1.11 min.

1. customdid not exceed 0° C
2. additionadded portion-wise to
3. customdid not exceed 0° C
4. temperatureThe resulting cream-colored suspension was warmed to 25° C.
5. stirringstirred at room temperature for 2-3 hrs
6. filtrationwas filtered under vacuum
7. washThe collected solid was washed with water and ether
8. customair dried

ORD record

ord-8238aaaf575e4f48b36341ada1cc796b

Source dataset

uspto-grants-2012_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08207166B2