Pyridine → HCID 20071725, compound

Acetazolamide (50 g) was stirred and heated at reflux in 500 ml 3N hydrochloric acid for half an hour. The cooled solution was made basic with 50% sodium hydroxide. The precipitated white solid 5-amino-1,3,4-thiadiazole-2-sulfonamide was collected (Compound 1, 28 g). It was dried further at 70° C. in a vacuum oven overnight. To a mixture of Compound 1 (4.5 g, 0.025 mole) and pyridine (2.42 ml, 0.03 mole) in 70 ml acetonitrile was added acetylsalicyloyl chloride (98%, 5 g, 0.025 mole). The reaction mixture warmed and became a clear solution. Solid deposits occurred slowly after stirring at room temperature for 1/2 hour. After two hours the solvent was evaporated; the residue was triturated with isopropyl alcohol/water for two hours and then filtered, rinsed in succession with isopropyl alcohol/water, isopropyl alcohol/isopropyl ether, 2×isopropyl ether. From the combined mother liquor and rinsings, a second crop was collected. Both the first and second crops were combined and dissolved in 50 ml N-methyl-2-pyrrolidone. The solution was filtered and the filtrate was treated with 15 ml 3N hydrochloric acid at 70° C. for half an hour. Upon dilution with 200 ml water, a white solid precipitated. The solid was collected, rinsed with water, and dried in a vacuum over at 80° C. overnight to 4.4 g of title compound, mp>250° C.

1. temperatureheated
2. customThe precipitated white solid 5-amino-1,3,4-thiadiazole-2-sulfonamide was collected (Compound 1, 28 g)
3. customIt was dried further at 70° C. in a vacuum oven overnight
4. temperatureThe reaction mixture warmed
5. customAfter two hours the solvent was evaporated
6. customthe residue was triturated with isopropyl alcohol/water for two hours
7. filtrationfiltered
8. washrinsed in succession with isopropyl alcohol/water, isopropyl alcohol/isopropyl ether, 2×isopropyl ether
9. customFrom the combined mother liquor and rinsings, a second crop was collected
10. dissolutiondissolved in 50 ml N-methyl-2-pyrrolidone
11. filtrationThe solution was filtered
12. additionthe filtrate was treated with 15 ml 3N hydrochloric acid at 70° C. for half an hour
13. customUpon dilution with 200 ml water, a white solid precipitated
14. customThe solid was collected
15. washrinsed with water
16. dry with materialdried in a vacuum over at 80° C. overnight to 4.4 g of title compound, mp>250° C.

ORD record

ord-315a94b6ada94d0a86e299e295e4f14e

Source dataset

uspto-grants-1991_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04990523