Ethylamine → [4-(4,5-Dihydrooxazol-2-yl)-2-nitrophenyl]ethylamine

Temperature

65 °C

To a solution of intermediate 4-chloro-N-(2-hydroxyethyl)-3-nitrobenzamide (0.40 g, 1.6 mmol) in anhydrous DCM (20 mL) added dropwise thionyl chloride (0.29 mL, 4.0 mmol). After stirring 2 h the reaction mixture was diluted with chloroform and concentrated. The resulting yellow oil was diluted cautiously with 2.0 M solution of ethylamine in THF (10 mL, 20 mmol) and heated in a sealed tube at 65° C. After 2 h the reaction mixture was cooled, concentrated and diluted with THF (20 mL). This solution was combined with an aqueous solution of 20% KOH (5 mL) and tetrabutylammonium bromide (20 mg). After stirring rapidly 2 h the mixture was extracted with Et2O (2×100 mL). The combined organic layers were washed with water and brine, dried (MgSO4), concentrated and chromatographed (silica gel, MeOH/DCM, 1:19) to yield [4-(4,5-dihydrooxazol-2-yl)-2-nitrophenyl]ethylamine (0.17 g, 45%) as a yellow solid. TLC (1:19 MeOH/DCM Rf 0.56).

1. concentrationconcentrated
2. temperatureAfter 2 h the reaction mixture was cooled
3. concentrationconcentrated
4. additiondiluted with THF (20 mL)
5. stirringAfter stirring rapidly 2 h the mixture
6. extractionwas extracted with Et2O (2×100 mL)
7. washThe combined organic layers were washed with water and brine
8. dry with materialdried (MgSO4)
9. concentrationconcentrated
10. customchromatographed (silica gel, MeOH/DCM, 1:19)

ORD record

ord-0cf62bdfbbb045d687bb1d4a5a0b614b

Source dataset

uspto-grants-2004_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06696473B2