Pyridine → 3,6-Dichloro-4h-thieno[3,2-e][1,2,4]thiadiazine 1,1-dioxide

A suspension of 6-chloro-2,3-dihydro-3-oxo-4H-thieno[3,2-e]-1,2,4-thiadiazine 1,1-dioxide (10.75 g, 0.045 mol) in phosphorus oxychloride (100 ml) was cooled on an ice bath and dry pyridine (7.3 ml, 0.09 mol) was added dropwise at such a rate that the temperature did not exceed 10° C. The mixture was then heated at 95°-100° C. for 16 h, and cooled to room temperature. A yellow precipitate was removed by filtration, and the filtrate was concentrated in vacuo. To the residue was added 200 g of ice, and the resulting mixture was stirred for 1 h, and filtered. The isolated solid was dissolved in saturated aqueous sodium hydrogen carbonate (100 ml), and filtered to remove a small amount of insoluble material. After treatment with decolorising charcoal the filtrate was adjusted to pH 2 with 4M hydrochloric acid and the precipitate that formed was filtered, washed with water and dried to yield 5.55 g (48%) of the title compound; mp >240° C. decomp.

1. temperaturewas cooled on an ice bath
2. customdid not exceed 10° C
3. temperatureThe mixture was then heated at 95°-100° C. for 16 h
4. customA yellow precipitate was removed by filtration
5. concentrationthe filtrate was concentrated in vacuo
6. additionTo the residue was added 200 g of ice
7. filtrationfiltered
8. dissolutionThe isolated solid was dissolved in saturated aqueous sodium hydrogen carbonate (100 ml)
9. filtrationfiltered
10. customto remove a small amount of insoluble material
11. customthe precipitate that formed
12. filtrationwas filtered
13. washwashed with water
14. customdried

ORD record

ord-5691e0c8cb33451f96702c01f343d169

Source dataset

uspto-grants-1999_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05889002