Synthesis
General procedure for the synthesis of 2-chlorobenzoxazole from 2-mercaptobenzoxazole: 2-mercaptobenzoxazole (10 mmol, 1.51 g) was suspended in SOCl2 (50 mL), and a few drops of DMF were added as catalyst. The reaction mixture was heated to reflux for 5 hours. After completion of the reaction, the solvent was removed by evaporation. The crude product was purified by silica gel column chromatography (eluent: petroleum ether/EtOAc, 10:1) to afford the target compound as a colorless oil in 69.7% yield.
Purification Methods
Purify it by fractional distillation, preferably in a vacuum. [Siedel J Prakt Chem 42 456 1890, Katz J Am Chem Soc 75 712 1953, Meyer & Sigel J Org Chem 42 2769 1977, Beilstein 27 H 43, 27 II 17.]
References
[1] Patent: US4517370, 1985, A
[2] Heteroatom Chemistry, 2001, vol. 12, # 3, p. 151 - 155
[3] Bioorganic and Medicinal Chemistry, 2016, vol. 24, # 21, p. 5374 - 5379
[4] Patent: CN108794421, 2018, A. Location in patent: Paragraph 0028-0030
[5] Tetrahedron, 1986, vol. 42, # 14, p. 3905 - 3912
