反应详情

A slurry of 100 g (760 mmol) of 4-hydroxy-L-proline in 600 mL of absolute ethanol was treated with dry hydrogen chloride until homogeneous. The solution was heated to the reflux temperature for 2 h. Upon cooling in the refrigerator, the product was obtained as white needles which were filtered, washed well with ether, and dried under reduced pressure to yield 141 g (95%) of (5): mp 153°-153.5° C. (lit. mp-147°-148° C.). 1H NMR (DMSO d6) δ1.25 (t, 3H, J=7 Hz), 4,20 (q, 2H, J=7 Hz). 13C NMR (D2O) 24.1, 47.1, 63.6, 68.7, 73.8, 79.1, 177.5; IR (KBr) 3320, 1735 cm-1.

1. temperatureThe solution was heated to the reflux temperature for 2 h
2. temperatureUpon cooling in the refrigerator
3. customthe product was obtained as white needles which
4. filtrationwere filtered
5. washwashed well with ether
6. customdried under reduced pressure