Diisobutylaluminum hydride → HCID 67454308, compound

Temperature

-78 °C

Into a 5000-mL 3-necked round-bottom flask purged and maintained with an inert atmosphere of nitrogen was placed a solution of methyl 5-bromo-2-cyclopropyloxazole-4-carboxylate (120 g, 487.80 mmol, 1.00 equiv.) in tetrahydrofuran (1200 mL). This was followed by the addition of DIBAL-H (1200 mL, 4.00 equiv., 25%) dropwise with stirring at −78° C. over 15 minutes. The resulting solution was stirred for 2 hours at −78˜−10° C., then quenched by the addition of 2000 mL of 2N HCl. The resulting solution was extracted with 3×3000 mL of ethyl acetate. The organic layers were combined, dried over anhydrous sodium sulfate and concentrated under vacuum. The crude product was re-crystallized from EAOAc:PE in the ratio of 1:20. This resulted in 70 g (66% yield) of ethyl 5-bromo-2-cyclopropyloxazole-4-carboxylate as a white solid. LC-MS (ES, m/z): 218 [M+H]+. H1NMR (400 MHz, CDCl3) δ: 4.459 (2H, s), 2.011˜2.065 (1H, m), 1.628 (1H, br), 1.020˜1.106 (4H, m).

1. customInto a 5000-mL 3-necked round-bottom flask purged
2. temperaturemaintained with an inert atmosphere of nitrogen
3. stirringThe resulting solution was stirred for 2 hours at −78˜−10° C.
4. customquenched by the addition of 2000 mL of 2N HCl
5. extractionThe resulting solution was extracted with 3×3000 mL of ethyl acetate
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated under vacuum
8. customThe crude product was re-crystallized from EAOAc

ORD record

ord-599128bcac354abdb8f51c0dee13ace0

Source dataset

uspto-grants-2015_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09073879B2