tert-Butyl isothiocyanate → ethyl (2R)-6-{[(benzyloxy)carbonyl]amino}-2-{[(tert-butylamino)carbothioyl]amino}hexanoate

Participants

Reaction Conditions

Reaction Steps

The process is performed as in Example 2, starting with 7.4 g of ethyl (2R)-2-amino-6-{[(benzyloxy)carbonyl]-amino}hexanoate with 5 cm3 of tert-butyl isothiocyanate in 200 cm3 of anhydrous ethanol at a temperature in the region of 20° C. for 20 hours. The reaction is completed by addition of a further 1 cm3 of isothiocyanate and heating for 2 hours at a temperature in the region of 80° C. The reaction medium is concentrated under reduced pressure (5 kPa) at a temperature in the region of 40° C. The residue obtained is taken up in ether and concentrated again under the above conditions. 13 g of ethyl (2R)-6-{[(benzyloxy)carbonyl]amino}-2-{[(tert-butylamino)carbothioyl]amino}hexanoate are obtained in the form of a colorless oil. (αD20=−12.5±0.5 at a concentration of 0.5% in methanol).

Provenance & Evidence