4-Nitrobenzyl chloroformate → HCID 13175759, compound

Participants

Reaction Steps

Saturated aqueous NaHCO3 (8 ml) was added dropwise to an ice-cold, stirring mixture of (S)-(+)-1-amino-2-propanethiol hydrochloride (363 mg, 2.85 mmol) in Et2O (75 ml) and H2O (8 ml) and the resulting slurry was stirred in the cold for 30 min. A solution of p-nitrobenzyl chloroformate (693 mg, 3.21 mmol) in Et2O (25 ml) was then added dropwise over 35 min. After having been stirred in the cold an additional 50 min., the reaction mixture was transferred to a separately funnel and the layers were separated. The organic portion was washed with ice-cold 0.025N HCl and brine, dried with MgSO4, filtered, and evaporated under a vacuum to a yellow oil (886 mg) which solidified on standing. The crude product was purified by preparative TLC on four 0.1×20×40 cm silica gel GF plates using 30:1 CH2Cl2 -EtOAc as developing solvent. The product band provided a yellow oil (667 mg) which crystallized on scratching. Recrystallization from Et2O-petroleum ether offorded the title compound B3) in two crops; crop 1 consisted of tiny, white crystals (216 mg) having mp 55.5°-60.5° and crop 2 afforded larger, off-white crystals (284 mg) having mp 55.5°-62°, [α]D +21.5° (Cl.32 in CHCl3).

Provenance & Evidence