Formaldehyde → Benzoxazines

A 500 mL flask was charged with resorcinol (33 g, 300 mmol), 3-amino-1-propanol vinyl ether (61 g, 600 mmol), and paraformaldehyde (38 g, 1260 mmol). Approximately 200 g of toluene was added and the mixture was heated to reflux. Reflux continued until water ceased to collect in the trap (about one hour). The reaction mixture was then cooled to room temperature. A large volume of solid byproduct formed in the reaction vessel. The toluene solution was decanted from the solid, and the remaining solid was washed with extra toluene. All of the toluene fractions were combined in a separatory funnel. The toluene solution was washed with a 5% NaOH solution, followed by a saturated NaCl solution. The toluene solution was dried with magnesium sulfate, and filtered over a small bed of neutral alumina. Removal of the solvent under reduced pressure produced about 50 g of an orange colored liquid (46% yield).

1. temperaturethe mixture was heated to reflux
2. temperatureReflux
3. customto collect in the trap (about one hour)
4. customA large volume of solid byproduct formed in the reaction vessel
5. customThe toluene solution was decanted from the solid
6. washthe remaining solid was washed with extra toluene
7. customAll of the toluene fractions were combined in a separatory funnel
8. washThe toluene solution was washed with a 5% NaOH solution
9. dry with materialThe toluene solution was dried with magnesium sulfate
10. filtrationfiltered over a small bed of neutral alumina
11. customRemoval of the solvent under reduced pressure

ORD record

ord-52afd9dfcd5240d0bf12dbf520b575ce

Source dataset

uspto-grants-2004_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06743852B2