反应详情

To a suspension of 5-amino-2-pyridinesulfonamide (7.0 g, 0.040 mol, C. Komfeld, J. Amer. Chem. Soc. 1695 (1942)) in conc HCl (60 mL) and H2O (20 mL), sodium nitrite (3.6 g, 0.052 mol) in H2O (50 mL) was added dropwise at 0° C. and the mixture was stirred for 30 min. The mixture changed to yellow brown solution and tin(II) chloride dihydrate (36 g, 0.16 mol) in conc HCl (30 mL) was added dropwise below 5° C. and stirred for 1 hour at 0° C. The mixture was made basic by addition of aqueous NaOH (pH=8). The resultant suspension was added THF (400 mL) and stirred for 10 min. The white precipitate was separated by celite filtration and washed with THF (100 mL×3). The filtrate was separated in two phase and organic phase was separated. Water phase was extracted with THF (150 mL×2), dried (MgSO4), and concentrated in vacuo gave brown oil. The oil was disolved in 10% HCl-MeOH (50 mL) and concentrated in vacuo gave brown amorphous solid. Crystallization from CH2Cl2 gave the titled compound as a brown solid (5.0 g, 56%).

1. additionwas added dropwise at 0° C.
2. additionwas added dropwise below 5° C.
3. stirringstirred for 1 hour at 0° C
4. stirringstirred for 10 min
5. customThe white precipitate was separated by celite filtration
6. washwashed with THF (100 mL×3)
7. customThe filtrate was separated in two phase and organic phase
8. customwas separated
9. extractionWater phase was extracted with THF (150 mL×2)
10. dry with materialdried (MgSO4)
11. concentrationconcentrated in vacuo
12. customgave brown oil
13. concentrationconcentrated in vacuo
14. customgave brown amorphous solid
15. customCrystallization from CH2Cl2