Ammonium Chloride → 4H,6H-Pyrazolo[1,5-c][1,3]thiazole-2-carbaldehyde

Temperature

-45 °C

The dry dichloromethane (8 mL) solution of dimethylsulfoxide (2.2 mL) was added dropwise to the dry dichloromethane (110 mL) solution of oxalyl chloride (2.0 mL) at −78° C. The reaction mixture was stirred for 15 min at the same temperature. The dry dichloromethane (40 mL) solution of (4H-5-thia-1,6a-diazapentalen-2-yl)methanol, (1.7 g) was added dropwise to the reaction mixture at −78° C., and stirring was continued for an additional 15 min. The reaction mixture was allowed to warm to −45° C. and stirred for 1 h. Triethylamine (11.3 mL) was added dropwise and the reaction mixture was allowed to warm to 0° C. After 20 min, saturated ammonium chloride solution (50 mL) and water (100 mL) were added and separated. The aqueous layer was extracted with AcOEt (3×150 mL). The combined organic layers were washed with water (200 mL) and brine (200 mL), dried (MgSO4) and filtered. The filtrate was concentrated under reduced pressure. The residue was applied to silica gel column chromatography, then the column was eluted with hexane-AcOEt (1:1). The titled compound was obtained as a yellow solid (1.7 g, quant.).

1. stirringstirring
2. waitwas continued for an additional 15 min
3. stirringstirred for 1 h
4. temperatureto warm to 0° C
5. waitAfter 20 min
6. customseparated
7. extractionThe aqueous layer was extracted with AcOEt (3×150 mL)
8. washThe combined organic layers were washed with water (200 mL) and brine (200 mL)
9. dry with materialdried (MgSO4)
10. filtrationfiltered
11. concentrationThe filtrate was concentrated under reduced pressure
12. washthe column was eluted with hexane-AcOEt (1:1)

ORD record

ord-1e4c90d8bc214111ab6df3dd8ffe5446

Source dataset

uspto-grants-2006_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07112582B2