反応 #56157

反応方程式

crotonaldehyde

hydrogen chloride

sodium hydroxide

5-chlorosalicylhydroxamic acid

→

7-chloro-2-methyl-3,3a-dihydro-2H,9H-isoxazolo (3,2-b) (1,3) benzoxazin-9-one

収率 57.6%

溶媒

tetrahydrofuran

water

反応条件

後処理

1. 1
   その他are passed in at a temperature of about 20°-30° C
2. 2
   その他to rise to about 31° C
3. 3
   温度The reaction temperature is maintained from about 30° C. to about 40° C. during the alkali addition
4. 4
   workup.ADDITIONWhen the addition
5. 5
   温度is heated to about 50° C. in vacuo for approximately one-half hour in order
6. 6
   その他to remove as much tetrahydrofuran as possible
7. 7
   その他A solid precipitates which
8. 8
   workup.ADDITIONis diluted with 600 ml
9. 9
   温度of water, cooled
10. 10
    ろ過filtered
11. 11
    洗浄washed with excess water
12. 12
    その他pulled dry
13. 13
    workup.DISSOLUTIONdissolved in 900 ml
14. 14
    ろ過of boiling isopropanol, the solution is filtered hot
15. 15
    洗浄the reactor rinsed with 100 ml
16. 16
    温度The filtrate is cooled overnight
17. 17
    その他to crystallize
18. 18
    ろ過The crystals are filtered
19. 19
    洗浄washed with isopropanol
20. 20
    その他dried at about 100° C

実験手順

400 ml. of tetrahydrofuran is combined with 100 gm. crotonaldehyde and placed in an ice bath. 125 gm. of hydrogen chloride are passed in at a temperature of about 20°-30° C. 182 gm. of 5-chlorosalicylhydroxamic acid is added in one portion and the reaction temperature is allowed to rise to about 31° C. The mixture is stirred at room temperature for about two hours and then 273 gm. of 50% w/w sodium hydroxide diluted with water to 600 ml. is dripped in. The reaction temperature is maintained from about 30° C. to about 40° C. during the alkali addition. When the addition is completed the mixture is heated to about 50° C. in vacuo for approximately one-half hour in order to remove as much tetrahydrofuran as possible. A solid precipitates which is diluted with 600 ml. of water, cooled, filtered and washed with excess water and pulled dry. The crude cake is returned to the reactor and dissolved in 900 ml. of boiling isopropanol, the solution is filtered hot and the reactor rinsed with 100 ml. hot isopropanol. The filtrate is cooled overnight to crystallize. The crystals are filtered, washed with isopropanol and dried at about 100° C. 134 gm. of 7-chloro-2-methyl-3,3a-dihydro-2H,9H-isoxazolo (3,2-b) (1,3) benzoxazin-9-one (m.p. 147° C.-151° C.) for a yield of 57.6% is obtained.

出典