Diisopropylethylamine → 1-Hydroxybenzotriazole

Participants

Reaction Steps

Nvan—(N-Fmoc-2-n-decylaminoethyl) vancomycin (100 mg, 48 umol, 1-0 eq) was dissolved in 1 mL DMF and glucosamine hydrochloride was added (31 mg, 144 mmol, 3.0 eq). The mixture was stirred vigorously for 30 minutes (the glucosamine hydrochloride did not fully dissolve), DIPEA (60 uL, 344 umol, 7.2 eq) was added and the mixture stirred vigorously for a further 30 minutes. A solution of benzotriazole-t-yl-oxy-tris-pyrrolidino-phosphonium hexafluorophosphate (PyBOP, 50 mg, 96 umol, 2.0 eq) and 1-hydroxybenzotriazole (14 mg, 104 umol, 2.2 eq) in 500 uL DMF was prepared. The PyBOP solution was added in 5 batches of 60 uL at intervals of 5 minutes to the vigorously stirred suspension of the other reaction components. The reaction was stirred an additional 30 minutes then precipitated into acetonitrile. The solid was collected by centrifugation, taken up in 1 mL N,N-dimethylformamide and treated with 200 uL piperidine for 30 minutes. Precipitation into ether was followed by centrifugation and the solid washed with acetonitrile. Reverse-phase preparative HPLC (10-70% acetonitrile in water containing 0.1% trifluoroacetic acid over 120 minutes) gave a compound of formula III where R15 is —CH2CH2—NH—(CH2)9CH3 and R22 is —N-(D-glucosamine as its trifluoroacetate salt.

Provenance & Evidence