Sulfuric Acid → N6-[(Phenylmethoxy)carbonyl]-L-lysine 1,1-dimethylethyl ester

Participants

Reaction Conditions

Reaction Steps

Into two separate 500 ml hydrogenation vessels each containing 100 ml of dioxane and 9.0 ml (160 mmol) of concentrated sulfuric acid was placed 11.0 gm (39.2 mmol) and 10.6 gm (37.8 mmol) of Nε-benzyloxycarbonyl-L-lysine. The two solutions were cooled to -78° C. and 140 ml of condensed (-78° C.) isobutylene was added to each vessel. The mixtures were then mechanically shaken (Parr shaker) at room temperature for 4 hours (26 psi). The reaction mixtures were combined and poured into 1000 ml (1.0 mol) of an ice cold solution of 1.0N aqueous sodium hydroxide and subsequently extracted three times with ether. The organic portions were combined (ca. 3000 ml), washed once with brine, dried over magnesium sulfate, filtered and concentrated in vacuo to give 16.7 gm (64%) of t-butyl Nε-benzyloxycarbonyl-L-lysinate (IV-A) as an oil.

Provenance & Evidence