Ethyl orthoformate → 1,3-Benzoxazol-6-ol

4-Aminoresorcinol hydrochloride (3.0 g, 18.5 mM), triethylorthoformate (9.1 g, 61.4 mM), and pyridinium-p-toluenesulfonate (PPTS, 250 mg, 1.0 mM) were refluxed in xylenes (200 mL) for about 18 hours. The reaction mixture was concentrated and the residue dissolved in ethyl acetate (200 mL) and washed with H2O (3×150 mL). The combined aqueous layer was back extracted with ethyl acetate (200 mL) and the combined organic layer was dried over MgSO4. Filtration and concentration provided an oil that was filtered through a silica gel column eluted with 1% methanol/methylene chloride to provide a brown solid, 1.66 g; m.p., 118-121° C.

1. concentrationThe reaction mixture was concentrated
2. dissolutionthe residue dissolved in ethyl acetate (200 mL)
3. washwashed with H2O (3×150 mL)
4. extractionThe combined aqueous layer was back extracted with ethyl acetate (200 mL)
5. dry with materialthe combined organic layer was dried over MgSO4
6. filtrationFiltration and concentration
7. customprovided an oil that
8. filtrationwas filtered through a silica gel column
9. washeluted with 1% methanol/methylene chloride
10. customto provide a brown solid, 1.66 g
11. customm.p., 118-121° C.

ORD record

ord-896820bacf654589b1ceb2aef76713c2

Source dataset

uspto-grants-2000_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06130217