Furfural → (E)-3-(furan-2-ylmethylene)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)indolin-2-one

HRID 661053Notes

Reaction equation

[CH3:1][C:2]1([CH3:19])[C:6]([CH3:8])([CH3:7])[O:5][B:4]([C:9]2[CH:10]=[C:11]3[C:15](=[CH:16][CH:17]=2)[NH:14][C:13](=[O:18])[CH2:12]3)[O:3]1.N1CCCCC1.[O:26]1[CH:30]=[CH:29][CH:28]=[C:27]1[CH:31]=O>C(O)C>[O:26]1[CH:30]=[CH:29][CH:28]=[C:27]1/[CH:31]=[C:12]1/[C:13](=[O:18])[NH:14][C:15]2[C:11]/1=[CH:10][C:9]([B:4]1[O:3][C:2]([CH3:19])([CH3:1])[C:6]([CH3:7])([CH3:8])[O:5]1)=[CH:17][CH:16]=2

Participants

Conditions

Temperature: 80 °C

Procedure

5-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)indolin-2-one (2.00 g, 7.7 mmol), ethyl alcohol (77 mL), piperidine (0.15 mL, 1.5 mmol), and 2-furaldehyde (0.77 mL, 9.3 mmol) were added to a 250 mL round-bottomed flask. The flask was sealed under a septum and heated to 80° C. for 5 hours. The mixture was cooled and filtered through a medium glass frit. The filtrate was adsorbed onto a plug of silica gel and chromatographed through a Redi-Sep® pre-packed silica gel column (120 g), eluting with a gradient of 0% to 70% EtOAc in hexane. The combined fractions were evaporated, and the product was crystallized out of EtOAc and hexanes at −20° C. to give (E)-3-(furan-2-ylmethylene)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)indolin-2-one (1.02 g, 39%) as an orange solid. LCMS (M+H) 338.1 calc. for C19H21BNO4338.1.

Workup

customThe flask was sealed under a septum
temperatureThe mixture was cooled
filtrationfiltered through a medium glass frit
customchromatographed through a Redi-Sep® pre-packed silica gel column (120 g)
washeluting with a gradient of 0% to 70% EtOAc in hexane
customThe combined fractions were evaporated
customthe product was crystallized out of EtOAc and hexanes at −20° C.

Sources & evidence

ORD record: ord-bb2368a427e045768ba0e279a031f08a
Source dataset: uspto-grants-2011_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08084479B2

Reaction notes

Loading…