(2S)-2-[(2-甲基丙烷-2-基)氧羰基氨基]戊二酸

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 1077 g (4.36 mols) of Boc-L-Glu, 2, was dissolved in 1 L of CH3CN with warming. This was poured into a 5 L three neck flask. To this solution 3 L of benzene, 196 g (6.54 mols) of paraformaldehyde, and 40 g (0.26 mols) of p-toluene sulfonic acid were added. Equipping the round bottom flasks with two Dean-Stark apparati, dual condensers at −10° C., and a mechanical stirrer, the reaction mixture was brought to 70° C. and refluxed for 6 hours (100 ml of water was collected from the Dean-Stark apparati indicating complete reaction). The reaction mixtures, clear reddish-brown solutions, were allowed to cool to room temperature, and were rotoevaporated to a reddish-brown oil. The oil was redissolved in 2 L of ether and was extracted three times with 1 L each of water. The aqueous layers were combined and were extracted with 2 L of ether to remove the product which was in the water. Both ether layers were combined, dried over Na2SO4, filtered, and roto-evaporated to a clear yellow oil. This was dried in vacuo to obtain 952 g (3.67 mols), 84.3% yield of impure 3. with warming at −10° C. a mechanical stirrer, the reaction mixture was brought to 70° C. was collected from the Dean-Stark apparati reaction) The reaction mixtures, clear reddish-brown solutions was extracted three times with 1 L each of water were extracted with 2 L of ether to remove the product which dried over Na2SO4 filtered roto-evaporated to a clear yellow oil This was dried in vacuo to obtain 952 g (3.67 mols), 84.3% yield of impure 3