反应详情

A solution of borane tetrahydrofuran complex, 1.0 M in tetrahydrofuran (4.76 mL, 4.76 mmol) was added dropwise to a mixture of N-(4-methoxybenzyl)-3-oxo-N-(1,2,4-thiadiazol-5-yl)-3,4-dihydro-2H-benzo[b][1,4]oxazine-7-sulfonamide (INTERMEDIATE K, 1.372 g, 3.17 mmol) in THF (15.86 mL) to form a heterogeneous mixture at 0° C. Gas evolution was observed upon addition, as well as gradual solubilization. After the addition, the reaction was warmed to RT for 5 h. The reaction was then quenched with MeOH (16.0 mL) and stirred overnight at room temperature. The reaction was then concentrated under a vacuum, and re-diluted with MeOH, and concentrated (×2). The resulting material was diluted once more in methanol and the solids were triturated and filtered, washing with methanol to yield 1.122 g of INTERMEDIATE L, N-(4-methoxybenzyl)-N-(1,2,4-thiadiazol-5-yl)-3,4-dihydro-2H-benzo[b][1,4]oxazine-7-sulfonamide (1.122 g, 2.68 mmol, 85%). 1H NMR (400 MHz, DMSO-d6) δ ppm 3.34-3.38 (m, 2 H) 3.72 (s, 3 H) 4.10 (t, J=4.40 Hz, 2 H) 5.03 (s, 2 H) 6.62-6.66 (m, 1 H) 6.82-6.89 (m, 2 H) 7.04 (d, J=2.35 Hz, 1 H) 7.16-7.21 (m, 1 H) 7.25-7.31 (m, 2 H) 8.35 (s, 1 H). m/z (ESI) 418.8 (M+H)+.

1. customto form a heterogeneous mixture at 0° C
2. additionGas evolution was observed upon addition
3. additionAfter the addition
4. customThe reaction was then quenched with MeOH (16.0 mL)
5. concentrationThe reaction was then concentrated under a vacuum
6. additionre-diluted with MeOH
7. concentrationconcentrated (×2)
8. additionThe resulting material was diluted once more in methanol
9. customthe solids were triturated
10. filtrationfiltered
11. washwashing with methanol