Hydrogen Sulfide → 2-Methyl-4,5-trimethylene-4-isothiazolin-3-one

Temperature

0 °C

5 g of 2-(N-methylcarbamoyl)cyclopentanone are dissolved in 100 cc of anhydrous ethanol saturated by anhydrous HCl gas. Into this solution, cooled to 0° C., there is passed for 5 hours a current of H2S and HCl gas. After having de-gassed the reaction mixture, there is added, with agitation, 0.5 molar equivalent of sodium metaperiodate fixed on acidic alumina (Al2O3), the temperature being maintained at 0° C. One-half hour later the reaction mixture is filtered. The filtrate is concentrated under reduced pressure. The residue is taken up in a 1:1 mixture of ethyl acetate and water. The pH of the aqueous solution is then adjusted, with agitation, to about 6 by the addition of sodium bicarbonate. The aqueous phase is decanted, then extracted with chloroform. The chloroform phase is then dried on sodium sulfate, and concentrated. On evaporation, an amorphous white solid, melting at 111° C. is obtained. Mass spectroscopy gives the expected relative peak at m/e: 155 (C7H9NOS)

1. customAfter having de-gassed the reaction mixture, there
2. additionis added, with agitation, 0.5 molar equivalent of sodium metaperiodate
3. temperaturethe temperature being maintained at 0° C
4. filtrationOne-half hour later the reaction mixture is filtered
5. concentrationThe filtrate is concentrated under reduced pressure
6. additionThe residue is taken up in a 1:1 mixture of ethyl acetate and water
7. additionThe pH of the aqueous solution is then adjusted, with agitation, to about 6 by the addition of sodium bicarbonate
8. customThe aqueous phase is decanted
9. extractionextracted with chloroform
10. dry with materialThe chloroform phase is then dried on sodium sulfate
11. concentrationconcentrated
12. customOn evaporation
13. customan amorphous white solid, melting at 111° C. is obtained
14. customMass spectroscopy gives the expected relative peak at m/e

ORD record

ord-46ebe9ac9c08462d8bcbc26a70f37fe4

Source dataset

uspto-grants-1987_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04708959