反应 #41160

反应方程式

N′-(Tetrahydro-pyran-4-ylidene)-hydrazinecarboxylic acid tert-butyl ester

Sodium cyanoborohydride

HCl

→

(tetrahydro-pyran-4-yl)-hydrazine hydrochloride

收率 60.0%

溶剂

tetrahydrofuran

methanol

反应条件

后处理

1. 1
   其他resulting in effervescence
2. 2
   温度the mixture was heated
3. 3
   温度to reflux for 5-10 minutes
4. 4
   workup.ADDITIONwas slowly added
5. 5
   温度the mixture was heated
6. 6
   温度to reflux for 20 minutes
7. 7
   其他the solvent was removed in vacuo
8. 8
   其他The residue was triturated with hot isopropanol
9. 9
   温度cooled to room temperature
10. 10
    workup.ADDITIONdiluted with ether
11. 11
    温度chilled
12. 12
    过滤The solid was collected by filtration
13. 13
    workup.DISSOLUTIONThe solid was dissolved in the same THF-methanol mixture
14. 14
    workup.ADDITIONtreated with 6N HCl (10.5 mL)
15. 15
    温度at reflux for another 1.5 hours
16. 16
    温度After cooling to room temperature
17. 17
    过滤the reaction mixture was filtered
18. 18
    其他to remove a small amount of insoluble material
19. 19
    浓缩The filtrate was then concentrated in vacuo
20. 20
    workup.ADDITIONIsopropanol was added to the residue and solid
21. 21
    其他to crystallize out of solution
22. 22
    温度After chilling overnight
23. 23
    workup.ADDITIONether was added
24. 24
    过滤The solid was then collected by filtration
25. 25
    洗涤washed with ether
26. 26
    其他dried in vacuo

实验过程

N′-(Tetrahydro-pyran-4-ylidene)-hydrazinecarboxylic acid tert-butyl ester (5.210 g, 24.32 mmol) was dissolved in a mixture of dry tetrahydrofuran (22 mL) and dry methanol (30 mL). Sodium cyanoborohydride was added to the solution resulting in effervescence. When the effervescence subsided, the mixture was heated to reflux for 5-10 minutes. After cooling to room temperature 6N HCl (10.5 mL) was slowly added and then the mixture was heated to reflux for 20 minutes. After cooling to room temperature, the solvent was removed in vacuo. The residue was triturated with hot isopropanol and then cooled to room temperature, diluted with ether and chilled. The solid was collected by filtration and was found to be the reduced material but not completely deprotected. The solid was dissolved in the same THF-methanol mixture and treated with 6N HCl (10.5 mL) at reflux for another 1.5 hours. After cooling to room temperature, the reaction mixture was filtered to remove a small amount of insoluble material. The filtrate was then concentrated in vacuo. Isopropanol was added to the residue and solid quickly began to crystallize out of solution. After chilling overnight, ether was added followed by additional chilling. The solid was then collected by filtration, washed with ether and dried in vacuo to give (tetrahydro-pyran-4-yl)-hydrazine hydrochloride (2.22 g, 60%).

来源