반응 #1050851

반응 방정식

sodium hydroxide

sulfurous acid

hydroxylamine-O-sulfonic acid

lithium 2-methyl-2H-indazole-3-sulfinate

n-butyl lithium

2-methyl-2H-indazole

→

2-methyl-2H-indazole-3-sulfonamide

수율 58.0%

용매

water

water

hexane

ethyl ether

ethyl ether

반응 조건

후처리

1. 1
   workup.WAITfor 3 hours at a temperature of not higher than -20° C
2. 2
   기타After completion of the reaction
3. 3
   기타was returned to room temperature
4. 4
   workup.STIRRINGstirred for 12 hours
5. 5
   여과The product was subjected to filtration
6. 6
   기타The crystals were dried
7. 7
   기타to obtain crude lithium 2-methyl-2H-indazole-3-sulfinate
8. 8
   기타This product was used for the subsequent reaction without purification
9. 9
   온도under cooling with ice (not higher than 10° C.)
10. 10
    workup.ADDITIONThis solution was added all at once to a solution
11. 11
    workup.STIRRINGthe mixture was stirred for 12 hours at room temperature
12. 12
    기타Formed crystals
13. 13
    여과were collected by filtration

실험 절차

A solution containing 9.5 g (72 mmol) of 2-methyl-2H-indazole in 200 ml of ethyl ether, was cooled to -30° C., and 61.4 g (144 mmol) of n-butyl lithium (a 15% hexane solution) was dropwise added thereto. The mixture was stirred for one hour at the same temperature, and then an excess amount of sulfurous acid gas was blown thereinto for 3 hours at a temperature of not higher than -20° C. After completion of the reaction, the mixture was returned to room temperature, stirred for 12 hours and then diluted with ethyl ether. The product was subjected to filtration. The crystals were dried to obtain crude lithium 2-methyl-2H-indazole-3-sulfinate. This product was used for the subsequent reaction without purification. 48.8 g (430 mmol) of hydroxylamine-O-sulfonic acid was gradually added to a solution containing 17.2 g (430 mmol) of sodium hydroxide in water (300 ml) under cooling with ice (not higher than 10° C.). This solution was added all at once to a solution containing the crude lithium 2-methyl-2H-indazole-3-sulfinate previously prepared in water (100 ml), and then the mixture was stirred for 12 hours at room temperature. Formed crystals were collected by filtration to obtain 8.8 g (yield: 58%) of 2-methyl-2H-indazole-3-sulfonamide (slightly yellow granular crystals). Melting point: 181°-183° C.

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