Hydrochloric Acid → HCID 12767913, compound

In 250 ml of water were dissolved 18.9 g of 5-chlorothiosalicyclic acid and 26.5 g of sodium carbonate, and 25 g of α-bromo-γ-butyrolactone was added dropwise to the solution under ice-cooling, followed by stirring at room temperature for 21 hours. 100 ml of 3 N-HCl was added to the reaction solution at room temperature to acidify the solution, and the solution was subjected to extraction with ethyl acetate. The extract was washed with aqueous saturated solution of sodium chloride and dried, and then, the solvent was distilled off. The residue was dissolved in 300 ml of toluene and heated under reflux for 2 hours while distilling off the produced water. After cooling the solution, insolubles were filtered off, and the filtrate was evaporated to dryness under reduced pressure, resulting in crude α-[(2-carboxy-4-chlorophenyl)thio]-γ-butyrolactone. The crude product was dissolved in 200 ml of acetic anhydride and 40 ml of triethylamine, and heated under a stream of nitrogen at 130° C. for 10 minutes. The reaction solution was evaporated to dryness under reduced pressure and chromatographed on a column by use of 50 g of activated carbon, 50 g of silica gel and chloroform. Recrystallization from ethanol of the resulting crude crystals yielded 7.17 g of 5-chloro-4',5'-dihydrospiro[benzo[b]thiophene-2(3H),3'(2'H)-furan]-3,2'-dione as pale yellow needles. Melting point: 143°-143.5° C.

1. additionwas added dropwise to the solution under ice-
2. temperaturecooling
3. extractionthe solution was subjected to extraction with ethyl acetate
4. washThe extract was washed with aqueous saturated solution of sodium chloride
5. customdried
6. distillationthe solvent was distilled off
7. dissolutionThe residue was dissolved in 300 ml of toluene
8. temperatureheated
9. temperatureunder reflux for 2 hours
10. distillationwhile distilling off the produced water
11. temperatureAfter cooling the solution, insolubles
12. filtrationwere filtered off
13. customthe filtrate was evaporated to dryness under reduced pressure
14. customresulting in crude α-[(2-carboxy-4-chlorophenyl)thio]-γ-butyrolactone
15. customThe reaction solution was evaporated to dryness under reduced pressure
16. customchromatographed on a column by use of 50 g of activated carbon, 50 g of silica gel and chloroform
17. customRecrystallization from ethanol of the resulting crude crystals

ORD record

ord-9d3f202dd1b54f099b295222312db9cd

Source dataset

uspto-grants-1982_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04362740