反应详情

A mixture of 10 g. (0.07 moles) of 4-methyl-2-carboxythiazole and 50 ml. of thionyl chloride was refluxed for 22 hours and stirred for 72 hours at room temperature. The reaction mixture was concentrated under reduced pressure to a yellow oil which was flushed 2 times with methylene chloride. This acid chloride was slurried in 10 ml. of benzene. Not all went in solution and the insoluble material was removed by filtration. The benzene filtrate was added dropwise to a stirred, cooled and filtered solution of 15.4 g. (0.14 mole) of hydrated sodium sulfhydrate in 158 ml. of ethanol and 17.5 ml. of water at such a rate as to keep the temperature of the mixture at 10°-15°. After the addition was completed, the reaction mixture was stirred for 40 minutes at 5°-10° C. Most of the ethanol was removed under reduced pressure and the residue was dissolved in 90 ml. of water. The pH of the solution was lowered to 2.8 by addition of 6N hydrochloric acid and was maintained there while the mixture was extracted with 5 × 100 ml. of ethyl acetate. The extracts were combined, washed with ice water, dried over magnesium sulfate, filtered and evaporated to dryness to give a reddish solid. This was weighed, redissolved in 50 ml. of hot ethyl acetate and one equivalent of dicyclohexylamine was added. After a small amount of ether was added, crystals precipitated. After cooling for 1 hour they were removed by filtration, washed with ether and dried under high vacuum to give 10.81 g. (45.5%) of a yellow solid. NMR spectrum was consistent with the desired material.

1. additionA mixture of 10 g
2. concentrationThe reaction mixture was concentrated under reduced pressure to a yellow oil which
3. customwas flushed 2 times with methylene chloride
4. customthe insoluble material was removed by filtration
5. additionThe benzene filtrate was added dropwise to a stirred
6. temperaturecooled
7. filtrationfiltered solution of 15.4 g
8. customat 10°-15°
9. additionAfter the addition
10. stirringthe reaction mixture was stirred for 40 minutes at 5°-10° C
11. customMost of the ethanol was removed under reduced pressure
12. dissolutionthe residue was dissolved in 90 ml
13. additionThe pH of the solution was lowered to 2.8 by addition of 6N hydrochloric acid
14. temperaturewas maintained there while the mixture
15. extractionwas extracted with 5 × 100 ml
16. washwashed with ice water
17. dry with materialdried over magnesium sulfate
18. filtrationfiltered
19. customevaporated to dryness
20. customto give a reddish solid
21. dissolutionredissolved in 50 ml
22. customcrystals precipitated
23. temperatureAfter cooling for 1 hour they
24. customwere removed by filtration
25. washwashed with ether
26. customdried under high vacuum
27. customto give 10.81 g