Sodium Hydroxide → 5,7-Dichloro-2,3-dihydro-4-hydrazino-2-methylbenzofuran

Temperature

0 °C

2.19 g of 38A was suspended in 9 mL of concentrated H2SO4 and 9 mL of water at -5° C. A solution of 0.69 g of sodium nitrite in 4 mL of H2O was added slowly and the resulting solution was stirred at 0° C. for one hour. This solution was added slowly to a mixture of 4.51 g of tin (II) chloride in 15 mL of concentrated hydrochloric acid which was precooled to -10° C., so as to maintain -10° C. to -5° C. The mixture was slowly warmed to room temperature and stirred for 16 hours. With cooling, 50% sodium hydroxide solution was added to adjust the pH to 11. The mixture was extracted with ether. The extract was washed with water, brine, dried (MgSO4) and stripped of solvent to leave crude 5,7-dichloro-2,3-dihydro-4-hydrazino-2-methylbenzofuran (38B), as pale orange solid, m.p.: 59°-64° C.

1. customat -5° C
2. customwas precooled to -10° C.
3. temperatureso as to maintain -10° C. to -5° C
4. temperatureThe mixture was slowly warmed to room temperature
5. stirringstirred for 16 hours
6. temperatureWith cooling
7. extractionThe mixture was extracted with ether
8. washThe extract was washed with water, brine
9. dry with materialdried (MgSO4)

ORD record

ord-4941107002724fd0bc3e18701ec1c142

Source dataset

uspto-grants-1989_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04881967