Urea → 5-Benzyloxazol-2-amine

A mixture of 2-bromo-3-phenylpropionaldehyde (14.2 g, crude from above) and urea (7.2 g, 0.12 mol) were heated to reflux for 15 hours in 200 mL of ethanol. The solvent was evaporated to dryness and the residue was diluted with dichloromethane (250 mL) and then washed with sodium hydroxide (10% aqueous solution, 100 mL) and water (50 mL). The organic layer was extracted three times with hydrochloric acid (5% aqueous solution, 250 mL). The combined aqueous layers were adjusted to between pH 9 to 10 with a 10% aqueous solution of sodium hydroxide and then extracted three times with dichloromethane (300 mL). The organic layer was dried over sodium sulfate, evaporated to dryness, and purified by silica gel column chromatography to give a pale yellow solid. (1.6 g, 9.2 mmol, 9.2% from 3-phenyl-propionaldehyde). ESI-MS m/z calc. 174.1. found 175.1 1H NMR (CDCl3) (δ 7.32-7.22 (m, 5H), 6.39 (s, 1H), 4.72 (bs, 2H), 3.84 (s, 2H).

1. temperaturewere heated
2. customThe solvent was evaporated to dryness
3. additionthe residue was diluted with dichloromethane (250 mL)
4. washwashed with sodium hydroxide (10% aqueous solution, 100 mL) and water (50 mL)
5. extractionThe organic layer was extracted three times with hydrochloric acid (5% aqueous solution, 250 mL)
6. extractionextracted three times with dichloromethane (300 mL)
7. dry with materialThe organic layer was dried over sodium sulfate
8. customevaporated to dryness
9. custompurified by silica gel column chromatography
10. customto give a pale yellow solid

ORD record

ord-50bb968458174cb88118ff8cb0373484

Source dataset

uspto-grants-2013_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08431605B2