反应详情

First, 8.1 g of 2,6-dimethylacetanilide and 100 mL of toluene were put in a 200 mL three-neck flask, and stirred to be mixed. Then, 10 g of 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson's reagent) was added to this mixture, and heated and stirred at 120° C. for 2 hours to be reacted. The reaction solution was concentrated to give an oily substance. This oily substance was purified by silica gel column chromatography. As a developing solvent, hexane:ethyl acetate=5:1 was used. The resulting fraction was concentrated, so that N-(2,6-dimethylphenyl)thioacetanilide was prepared as a brown oily substance. The prepared oily substance, 3.4 g of sodium ethoxide, and 40 mL of ethanol were put in a 100 mL three-neck flask, and stirred at room temperature for 1 hour. Then, 4.0 mL of iodoethane was added to this mixture, and heated and stirred at 60° C. for 5 hours to be reacted. After the reaction, ethanol was distilled off under a reduced pressure to give a brown oily substance. This oily substance was dissolved in dichloromethane, and washed with water and then a saturated aqueous solution of sodium hydrogen carbonate. After the washing, anhydrous magnesium sulfate was added to the resulting organic layer for drying. The resulting mixture was subjected to gravity filtration, and the filtrate was concentrated, so that N-[1-(ethylsulfanyl)ethylidene]-2,6-dimethylaniline was prepared (a brown solid, crude yield: 76%). The synthetic scheme of Step 1 is shown by (a-4).

1. additionto be mixed
2. temperatureheated
3. stirringstirred at 120° C. for 2 hours
4. customto be reacted
5. concentrationThe reaction solution was concentrated
6. customto give an oily substance
7. customThis oily substance was purified by silica gel column chromatography
8. concentrationThe resulting fraction was concentrated, so that N-(2,6-dimethylphenyl)thioacetanilide
9. customwas prepared as a brown oily substance
10. stirringstirred at room temperature for 1 hour
11. temperatureheated
12. stirringstirred at 60° C. for 5 hours
13. customto be reacted
14. distillationwas distilled off under a reduced pressure
15. customto give a brown oily substance
16. washwashed with water
17. additionAfter the washing, anhydrous magnesium sulfate was added to the resulting organic layer
18. customfor drying
19. filtrationThe resulting mixture was subjected to gravity filtration
20. concentrationthe filtrate was concentrated, so that N-[1-(ethylsulfanyl)ethylidene]-2,6-dimethylaniline
21. customwas prepared (a brown solid, crude yield: 76%)