Dicyclohexylcarbodiimide → N-Ethyl-n-heptyl-4-(4-(methylsulfonamido)phenyl)-4-oxobutanamide

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A stirred solution of 4-[(methylsulfonyl)amino]-γ-oxobenzenebutanoic acid as prepared in Preparation 2 (12.0 g, 0.044 mol) in DMF (100 ml) under N2 is cooled in an ice bath to 5° C. and treated with 1-hydroxybenzotriazole (5.94 g, 0.044 mol) and N,N'-dicyclohexylcarbodiimide (9.08 g, 0.044 mol). After 1 hour, ethylheptylamine (6.3 g, 0.044 mol) is added; after an additional 30 minutes the ice bath is removed and the mixture is kept at ambient temperature for 18 hours. The reaction mixture is filtered over a Celite filter aid and the filtrate is concentrated under vacuum. The resulting material is dissolved in CH2Cl2 ; washed with dilute HCl, NaHCO3 and brine; dried (Na2SO4) and concentrated. The residue is chromatographed over silica gel (1.25 kg) with 5% MeOH:1% NH4OH:CH2Cl2. The N-ethyl-N-heptyl-γ-oxo-4-[(methylsulfonyl)amino]benzenebutanamide thus obtained is crystallized from EtOAc:SSB to yield 10.77 g, mp 100°-102° C. and 2.32 g, mp 99°-101° C. The analytical sample has a mp 102°-103° C.

Herkunft & Nachweise