Hydrochloric Acid → 7-Hydrazino-2,3dihydro-2-methylbenzofuran

A mixture of 157 ml of concentrated hydrochloric acid and 66.1 g of 1C was stirred at room temperature for one hour, then 485 ml of water was added. The mixture was warmed to 70° C., then allowed to cool and stand at room temperature for 18 hours, then cooled to 5° C. while a solution of 33.7 g of sodium nitrite in 48 ml of water was added drop-by-drop (over 20 minutes). The resulting solution was stirred at 5° C. for 1 hour, then added drop-by-drop (over 10 minutes) to a stirred mixture of 393.5 g of sodium sulfite in 755 ml of water, at 5° C. The resulting mixture was stirred at room temperature for 2 hours, then a slurry of 77.2 g of sodium dithionite in 100 ml of water was added, in portions, to the stirred mixture. The mixture was stirred for 2 hours at room temperature, then at 70° C. for 15 minutes, when 1 pound of potassium chloride was added. The mixture was stirred at room temperature for 18 hours, cooled to 4° C. and filtered. 125 g of the resulting solid product was mixed with 500 ml of methanol. The resulting suspension was stirred at 0° C. while an excess of anhydrous hydrogen chloride was added. The mixture was stirred for 1 hour at 0° C., then most of the methanol was evaporated under reduced pressure at room temperature. The mixture was mixed with 500 ml of cold water, made basic by addition of 50% aqueous sodium hydroxide solution, and extracted with ether. The extract was dried (MgSO4) and the solvent was evaporated to give 7-hydrazino-2,3dihydro-2-methylbenzofuran (1D), as an amber syrup.

1. temperatureThe mixture was warmed to 70° C.
2. temperatureto cool
3. waitstand at room temperature for 18 hours
4. additionwas added drop-by-drop (over 20 minutes)
5. stirringThe resulting solution was stirred at 5° C. for 1 hour
6. stirringThe resulting mixture was stirred at room temperature for 2 hours
7. stirringThe mixture was stirred for 2 hours at room temperature
8. waitat 70° C. for 15 minutes
9. stirringThe mixture was stirred at room temperature for 18 hours
10. temperaturecooled to 4° C.
11. filtrationfiltered
12. addition125 g of the resulting solid product was mixed with 500 ml of methanol
13. stirringThe resulting suspension was stirred at 0° C. while an excess of anhydrous hydrogen chloride
14. additionwas added
15. stirringThe mixture was stirred for 1 hour at 0° C.
16. custommost of the methanol was evaporated under reduced pressure at room temperature
17. additionThe mixture was mixed with 500 ml of cold water
18. additionmade basic by addition of 50% aqueous sodium hydroxide solution
19. extractionextracted with ether
20. dry with materialThe extract was dried (MgSO4)
21. customthe solvent was evaporated

ORD record

ord-14f0d8cfec564abcbf02ebb26268900e

Source dataset

uspto-grants-1985_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04554283