Carbon Dioxide → HCID 20519912, compound

Temperature

85 °C

A reactor was charged with 1,457.5 g of 3-chloro-4-isopropoxyphenylhydrazine hydrochloride and 5.5 l of toluene to which was slowly added 971.7 g of pyridine while stirring at 10°-15° C. The temperature was lowered to 5°-10° C. and 667.3 g of ethyl chloroformate was added over about 3 hours. The resulting mixture was stirred at 10°-20° C. for 2 hours, was washed with water and dried over MgSO4, and after filtration, evaporated to 4 liters. This solution was slowly added over about 3 hours to a stirred mixture of 3.7 l of toluene and 693 g of phosgene at 10°-15° C. The resulting mixture was stirred for about 3 hours at room temperature, then slowly heated to 85° C. to remove excess phosgene. The remaining mixture was cooled to 10° C. and 540 g of dimethylamine was added over about 3 hours while stirring and cooling to maintain a temperature of 10°-20° C. After stirring at room temperature for about 30 minutes, a solid product was filtered and washed with ether. The filtrate was evaporated to dryness, leaving a solid product. Washing the filter cake with water, left an oily residue which was triturated with ether to yield a white solid. To this solid combined with that obtained by evaporation of the filtrate was added 4.5 l of water, 960 g of 50% sodium hydroxide and 2.2 l of ethanol. The resulting mixture was heated at reflux for about 5 hours and then allowed to cool to room temperature. To this mixture 1.5 l of concentrated hydrochloric acid was slowly added while stirring. Carbon dioxide gas evolved. The resulting solution was then made basic by adding 500 ml of 50% sodium hydroxide while stirring. The resulting tan solid was filtered, air dried, triturated with hexane-ether (90:10) solution and, after filtration, dried to yield 957.3 g of solid product semicarbazide; melting point 73°-74° C.

1. customwas lowered to 5°-10° C.
2. stirringThe resulting mixture was stirred at 10°-20° C. for 2 hours
3. washwas washed with water
4. dry with materialdried over MgSO4
5. filtrationafter filtration
6. customevaporated to 4 liters
7. additionThis solution was slowly added over about 3 hours to a stirred mixture of 3.7 l of toluene and 693 g of phosgene at 10°-15° C
8. stirringThe resulting mixture was stirred for about 3 hours at room temperature
9. customto remove excess phosgene
10. temperatureThe remaining mixture was cooled to 10° C.
11. addition540 g of dimethylamine was added over about 3 hours
12. stirringwhile stirring
13. temperaturecooling
14. temperatureto maintain a temperature of 10°-20° C
15. stirringAfter stirring at room temperature for about 30 minutes
16. filtrationa solid product was filtered
17. washwashed with ether
18. customThe filtrate was evaporated to dryness
19. customleaving a solid product
20. washWashing the filter cake with water
21. waitleft an oily residue which
22. customwas triturated with ether
23. customto yield a white solid
24. customTo this solid combined with that obtained by evaporation of the filtrate
25. temperatureThe resulting mixture was heated
26. temperatureat reflux for about 5 hours
27. temperatureto cool to room temperature
28. stirringwhile stirring
29. stirringwhile stirring
30. filtrationThe resulting tan solid was filtered
31. customair dried
32. customtriturated with hexane-ether (90:10) solution
33. filtrationafter filtration
34. customdried

ORD record

ord-08eff6fbbbce421881a2e82aba2d1301

Source dataset

uspto-grants-1982_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04358611