Reaktion #155608

Reaktionsgleichung

sodium bicarbonate

N-{(4aR,6R,8aS)-8a-(5-bromo-2-fluorophenyl)-6-[(E)-2-methoxyethenyl]-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-yl}benzamide

trimethyl orthoformate

→

product

N-[(4aR,6R,8aS)-8a-(5-bromo-2-fluorophenyl)-6-(1,1,3,3-tetramethoxypropan-2-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-yl]benzamide

Lösungsmittel

dichloromethane

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeexceed 3° C
2. 2
   SonstigeThe organic layer was separated
3. 3
   Sonstigeresulting aqueous layer
4. 4
   Extraktionwas extracted with further dichloromethane (200 mL)
5. 5
   WaschenThe combined organics were washed with brine (200 mL)
6. 6
   Trocknendried over sodium sulfate
7. 7
   Filtrationfiltered
8. 8
   Einengenconcentrated

Vorschrift

To a solution of N-{(4aR,6R,8aS)-8a-(5-bromo-2-fluorophenyl)-6-[(E)-2-methoxyethenyl]-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-yl}benzamide (C43) (0.54 g, 1.1 mmol) in dichloromethane (2 mL) at 0° C., was added trimethyl orthoformate (0.239 mL, 2.19 mmol) followed by drop-wise addition of boron trifluoride-diethyl etherate (0.136 mL, 1.08 mmol), without letting the reaction temperature exceed 3° C. The resulting solution was allowed to stir at the same temperature for 1.5 hours. The reaction mixture was diluted with dichloromethane (200 mL) and a saturated aqueous solution of sodium bicarbonate (200 mL). The organic layer was separated and resulting aqueous layer was extracted with further dichloromethane (200 mL). The combined organics were washed with brine (200 mL), dried over sodium sulfate, filtered and concentrated to give the product (0.65 g) as a white solid, which was taken directly to the following step. 1H NMR (400 MHz, CD3OD) characteristic peaks: δ 8.23 (br d, J=7.0 Hz, 2H), 7.41-7.52 (m, 5H), 6.99 (dd, J=1.7, 9.0 Hz, 1H), 4.52 (dd, J=17.7, 4.2 Hz, 1H), 4.13 (d, J=12.5 Hz, 1H), 4.04 (d, J=8.4 Hz, 1H), 3.79 (d, J=11.9 Hz, 1H), 3.13-3.19 (m, 1H), 2.98 (dd, J=13.1, 2.7 Hz, 1H), 2.64 (dd, J=13.1, 1.3 Hz, 1H).

Quelle