تفاعل #56252

معادلة التفاعل

ammonium hydroxide

crotonaldehyde

hydrogen chloride

5-chlorosalicylhydroxamic acid

→

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

المردود 67.0%

المذيبات

tetrahydrofuran

water

ظروف التفاعل

المعالجة

1. 1
   أخرىare passed into the mixture at 20°-30° C
2. 2
   workup.DISSOLUTIONdissolves
3. 3
   درجة الحرارةThe mixture is cooled in a water bath
4. 4
   workup.STIRRINGwith stirring
5. 5
   workup.ADDITIONto rise to about 50° C. during the alkali addition
6. 6
   أخرىto remove as much tetrahydrofuarn as possible
7. 7
   أخرىA solid precipitates
8. 8
   درجة الحرارةwhile heating
9. 9
   workup.ADDITIONof water are added
10. 10
    درجة الحرارةthe entire mixture is cooled to about 10° C. in an ice bath
11. 11
    ترشيحThe solid is filtered
12. 12
    غسيلwashed with water
13. 13
    أخرىpulled dry
14. 14
    أخرىThe cake is recrystallized from 800 ml
15. 15
    أخرىboiling isopropanol refrigerated overnight
16. 16
    ترشيحThe crystals are filtered
17. 17
    غسيلwashed with cold isopropanol
18. 18
    أخرىdried at about 100° C

الإجراء التجريبي

360 ml. of tetrahydrofuran is combined with 90 gm. of crotonaldehyde and placed in an ice bath. 100 gm. of hydrogen chloride are passed into the mixture at 20°-30° C. 158 gm. of 5-chlorosalicylhydroxamic acid is added in one portion and the mixture stirred at 25°-30° C. for about two hours until the solid dissolves. The mixture is cooled in a water bath and 400 ml. of concentrated ammonium hydroxide diluted with 400 ml. of water is added with stirring. The temperature of the mixture is allowed to rise to about 50° C. during the alkali addition and the mixture is then heated on a steam bath to about 90° C. and a vacuum applied to remove as much tetrahydrofuarn as possible. A solid precipitates while heating. 400 ml. of water are added and the entire mixture is cooled to about 10° C. in an ice bath. The solid is filtered and washed with water and pulled dry. The cake is recrystallized from 800 ml. boiling isopropanol refrigerated overnight. The crystals are filtered, washed with cold isopropanol and dried at about 100° C. 136 gm. 7-chloro-2-methyl-3,3a-dihydro-2H, 9H-isoxazolo (3,2-b) (1,3) benzoxazin-9-one (m.p. 144°-148° C.) for a yield of 67% is obtained.

المصدر