Boron tribromide → 4-[2-(3-Pentyl-[1,2,4]oxadiazol-5-yl)-vinyl]-benzene-1,2-diol

Temperature

-42.5 °C

To a cooled solution of 1M boron tribromide (1.52 mL, 1.5 mmol) in 2 mL dichloromethane, 0.2 g (0.6 mmol) of 5-[2-(3,4-dimethoxy-phenyl)-vinyl]-3-pentyl-[1,2,4]oxadiazole (compound of Example 39) dissolved in 1 mL of dichloromethane was added over a period of 15-20 min at −40° C. to −45° C. The reaction mixture was stirred at −40 to −45° C. for 30-45 min and allowed to attain 25° C. to 30° C. slowly, over a period of 1 h. The reaction mixture was further stirred at 25° C. to 30° C. for 4-5 h. After the completion of the reaction, the reaction mixture was quenched with 10 mL of chilled 5% sodium bicarbonate solution, below 20° C. (pH: 8-9). 10 mL of ethyl acetate was added to the reaction mixture to dissolve the solid and stirred for 10-15 min. The organic layer was separated and the aqueous layer was washed with 10 mL of 10% sodium chloride solution. The organic layer was collected and distilled to obtain a crude residue, which was purified by column chromatography (silica gel, chloroform-methanol) to yield the title compound.

1. additionwas added over a period of 15-20 min at −40° C. to −45° C
2. customto attain 25° C. to 30° C.
3. waitover a period of 1 h
4. stirringThe reaction mixture was further stirred at 25° C. to 30° C. for 4-5 h
5. customAfter the completion of the reaction
6. customthe reaction mixture was quenched with 10 mL of chilled 5% sodium bicarbonate solution, below 20° C. (pH: 8-9)
7. addition10 mL of ethyl acetate was added to the reaction mixture
8. dissolutionto dissolve the solid
9. stirringstirred for 10-15 min
10. customThe organic layer was separated
11. washthe aqueous layer was washed with 10 mL of 10% sodium chloride solution
12. customThe organic layer was collected
13. distillationdistilled
14. customto obtain a crude residue, which
15. customwas purified by column chromatography (silica gel, chloroform-methanol)

ORD record

ord-19e217f8b7784e6d970283197abc8153

Source dataset

uspto-grants-2014_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08629277B2