Acetic Acid → Oxazole, 5-(diethoxymethyl)-

Temperature

-78 °C

Prepared according to the procedure of Scholikopf (J. Am. Chem. Soc. 112 (10) 4070 (1990)). To a solution of methyl isocyanide (2.88 g, 0.0702 mol) in THF (50 mL) under argon at -780 C was added dropwise n-butyllithium solution (1.6M in hexanes, 44 mL) over 15 mins. After stirring for an additional 20 mins at -78° C., a solution of ethyl diethoxyacetate (12.62 g, 0.0702 mol) in THF (15 mL) was added dropwise over 20 mins. The bath was allowed to warm to -30° C. over the next 2 hrs and the reaction was then stirred at 0° C. for 30 mins. The reaction was quenched at 0° C. with glacial HOAc (4.22 g, 0.0702 mol) and the solvent was removed by rotary evaporation in vacuo. The golden solid was partitioned with H2 0 (45 mL) and EtOAc (200 mL), and the aqueous extracted with EtOAc (2×200 mL). The combined organic was washed with satd aq NaCl, dried over Na2SO4, and concentrated in vacuo to a brown oil. Chromatography on a 300 g SiO2 flash column with a gradient of EtOAc/hexane (10%, 15%, 20%) afforded the desired compound as a colorless liquid (7.46 g, 0.0436 mol, 62%): 1H NMR (CDCl3) δ 1.25 (t, J=6.9 Hz, 6H), 3.56-3.70 (m, 4H), 5.62 (s, 1H), 7.26 (s, 1H), 7.86 (s, 1H). Mass spectrum: (M+H)+ =172.

1. customPrepared
2. temperatureto warm to -30° C. over the next 2 hrs
3. stirringthe reaction was then stirred at 0° C. for 30 mins
4. customthe solvent was removed by rotary evaporation in vacuo
5. customThe golden solid was partitioned with H2 0 (45 mL) and EtOAc (200 mL)
6. extractionthe aqueous extracted with EtOAc (2×200 mL)
7. washThe combined organic was washed with satd aq NaCl
8. dry with materialdried over Na2SO4
9. concentrationconcentrated in vacuo to a brown oil

ORD record

ord-3c6766d01bf84d25b38eff0f9882ed02

Source dataset

uspto-grants-1998_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05846987