Malonic Acid → Benzothiazole, 2,2'-methylenebis-

To a flask were added 50 g polyphosphoric acid. After heating to 70 C under nitrogen, a mixture of 3.13 g 2-aminothiophenol and 1.3 g malonic acid was added. The reaction mixture was heated to 135 C for 1 hour, then 145 C for 1 hour. After cooling to 70 C, the mixture was poured into 100 ml water. The slurry was cooled to 22 C, filtered and the solid was washed with water. The solid was added to 50 ml ethanol and basified with aqueous ammonium hydroxide. After cooling to 5 C, the solid was filtered and washed with water. The solid was dissolved in 14 ml hot ethanol and 7 ml water was added and the solution was cooled to 5 C. Following filtration, the white solid was washed with 50% ethanol and dried, leaving 1.1 g.

1. temperatureAfter heating to 70 C under nitrogen
2. additionwas added
3. temperatureThe reaction mixture was heated to 135 C for 1 hour
4. temperatureAfter cooling to 70 C
5. temperatureThe slurry was cooled to 22 C
6. filtrationfiltered
7. washthe solid was washed with water
8. additionThe solid was added to 50 ml ethanol and basified with aqueous ammonium hydroxide
9. temperatureAfter cooling to 5 C
10. filtrationthe solid was filtered
11. washwashed with water
12. dissolutionThe solid was dissolved in 14 ml hot ethanol
13. addition7 ml water was added
14. temperaturethe solution was cooled to 5 C
15. filtrationfiltration
16. washthe white solid was washed with 50% ethanol
17. customdried
18. customleaving 1.1 g

ORD record

ord-d61af41d872043f0a36e0808d9c552f8

Source dataset

uspto-grants-2015_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09011734B2