反应详情

温度

0 °C

Alternatively Intermediate 18 was prepared from Intermediate 16. To a suspension of lithium aluminium hydride (0.57 g, 15 mmol) in anhydrous THF (30 ml) was added the solution of (S)-6-aza-spiro[2.5]octane-5,6-dicarboxylic acid 5-benzyl ester 6-tert-butyl ester (intermediate 16, 3.45 g, 10 mmol) in THF(20 ml) at 0° C., after the addition was completed, the reaction mixture was stirred at 0° C. for 2 hours. The resulting mixture was quenched with Na2SO4.10H2O, filtered and the filtration was dried (Na2SO4) and evaporated to obtain a crude that was purified by silica gel chromatography (petroleum ether/ethyl acetate from 10/1 to 5/1). (S)-5-Hydroxymethyl-6-aza-spiro[2.5]octane-6-carboxylic acid tert-butyl ester was obtained as colourless oil (2.0 g), yield:83%.

1. additionafter the addition
2. customThe resulting mixture was quenched with Na2SO4.10H2O
3. filtrationfiltered
4. filtrationthe filtration
5. dry with materialwas dried (Na2SO4)
6. customevaporated
7. customto obtain a crude that
8. customwas purified by silica gel chromatography (petroleum ether/ethyl acetate from 10/1 to 5/1)