(Methoxycarbonylsulfamoyl)triethylammonium hydroxide → HCID 53888673, compound

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Reaction Steps

A solution of 10.0 g (0.0279 mol) of methyl (S)-3-hydroxy-2-(5-methyl-6-oxo-5,6-dihydro-4H-imidazo[1,5-a][1,4]benzodiazepin-3-ylcarbonylamino)-propionate in 500 ml of tetrahydrofuran was treated while gassing with argon with 7.25 g (0.0304 mol) of methoxycarbonylsulphamoyl-triethylammonium hydroxide internal salt (Burgess reagent) according to the method described in Tert. Letters 1992, 33, 907. The mixture was boiled at reflux for 1 hr. and completely freed from the solvents. The residue was dissolved in dichloromethane and chromatographed over silica gel with ethyl acetate/ethanol 9:1 as the eluent. There were obtained 4.4 g (46%) of methyl (S)-2-(5-methyl-6-oxo-5,6-dihydro-4H-imidazo[1,5-a][1,4]benzodiazepin-3-yl)-4,5-dihydro-oxazole-4-carboxylate as a white solid. An analytical sample was recrystallized from ethanol/diethyl ether and gave white crystals; m.p. 190°-192°. [α]D20 =+45.4° (CHCl3, c=1%).

Provenance & Evidence