反应详情

291 gm (2.5 mol) of chlorosulfonic acid were added in portions to 208 gm (1.0 mol) of phosphorus pentachloride while stirring and cooling. After the evolution of hydrogen chloride had subsided, 98 gm (1.0 mol) of 2-methyl-thiophene were added dropwise while stirring at a temperature of 10° C. When the addition was finished, the mixture was stirred for another 10 minutes. After pouring the reaction mixture over 2.5 kg of ice, the obtained sulfochloride was separated by extracting 5 times with 500 ml of ether. The organic phase was washed twice with 200 ml of water, dried and evaporated in vacuo. The residual oil was taken up in 200 ml of tetrahydrofuran and added, while stirring, dropwise to a solution of 183 gm (2.5 mol) of tert. butylamine in 100 ml of tetrahydrofuran at a temperature of 20° C. The mixture was stirred for 1 hour at room temperature and for 20 minutes at 70° C. bath temperature. The crystals of tert. butylamine hydrochloride which separated out were filtered off and washed with ether. The combined filtrates were evaporated, and the residue was taken up in ether. After washing with 2 N hydrochloric acid and water, the residue was dried over sodium sulfate and again evaporated. The obtained crude product was recrystallized from cyclohexane, yielding 182 gm (78% of theory) of N-tert.-butyl-5-methyl-thiophene-2-sulfonamide.

1. temperaturecooling
2. stirringwhile stirring at a temperature of 10° C
3. additionWhen the addition
4. stirringthe mixture was stirred for another 10 minutes
5. customthe obtained sulfochloride was separated
6. extractionby extracting 5 times with 500 ml of ether
7. washThe organic phase was washed twice with 200 ml of water
8. customdried
9. customevaporated in vacuo
10. additionadded
11. stirringThe mixture was stirred for 1 hour at room temperature and for 20 minutes at 70° C. bath temperature
12. customThe crystals of tert. butylamine hydrochloride which separated out
13. filtrationwere filtered off
14. washwashed with ether
15. customThe combined filtrates were evaporated
16. washAfter washing with 2 N hydrochloric acid and water
17. dry with materialthe residue was dried over sodium sulfate
18. customagain evaporated
19. customThe obtained crude product
20. customwas recrystallized from cyclohexane