Reaktion #58016

Reaktionsgleichung

compound 8

2,3,4-tri-O-benzylfucopyranose p-nitrobenzoate

HBr

→

fucopyranosyl-p-nitrobenzoate

2,3,4-tri-O-benzylfucopyranose p-nitrobenzoate

α-fucopyranosyl bromide

2,3,4-tri-O-benzyl-α-L-fucopyranosyl Bromide

Lösungsmittel

CH2Cl2

Reaktionsbedingungen

Vorschrift

Similarly, treatment of the β-isomer of the fucopyranosyl-p-nitrobenzoate (compound 8) (583 mg, 1 mmol) with a saturated solution of HBr in CH2Cl2 (5 mL) for 30 min at 5° C. furnished the α-fucopyranosyl bromide (550 mg). The NMR spectrum of this product was identical with that of α-bromide obtained earlier from the α-fucopyranosyl p-nitrobenzoate. However, due to the instability of the bromide, it was used as such immediately for the next step. 1H-NMR (CDCl3): 1.17 (d, 3H, J=6.45 Hz, CH3), 3.6-4.2 (m, OCH), 4.8-5.02 (m, OCH2), 6.53 (d, 1H, OCHBr), 7.2-7.5 (15H, Ar—H); 13C-NMR (CDCl3): 16.61 (CH3), 72.36 (OCH), 73.23 (OCH2), 74.00 (OCH2), 75.59 (OCH2), 76.57 (OCH), 74.49 (OCH), 80.02 (OCH), 95.26 (OCHBr), 127.97, 128.09, 128.23, 128.32, 128.43, 128.75, 128.86 (aromatic carbons).

Quelle