m-Chloroperbenzoic acid → Methyl 8-[bis-(tert-butoxycarbonyl)amino]-6-hydroxy-5,6-dihydro-pyrazolo[5,1-a]isoquinoline-7-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a cooled solution of methyl 6-[bis-(tert-butoxycarbonyl)amino]-3-(2H-pyrazol-3-yl)-2-vinylbenzoate (Intermediate 9, 2.4 g) in anhydrous DCM (100 mL) at 0° C. was added (S,S)-(+)-N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamino manganese (III) chloride (0.280 g) and N-methylmorpholine N-oxide (3.2 g). m-Chloroperbenzoic acid (3.8 g) was then added portionwise and the reaction mixture was stirred at 0° C. for 20 minutes. The resultant mixture was quenched by the addition of 2M aqueous sodium carbonate solution and the organic layer was separated, dried (MgSO4) and filtered. The filtrate was concentrated in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and DCM with a gradient of 0-100%. The resultant material was repurified by chromatography on silica, eluting with a mixture of ethyl acetate and DCM with a gradient of 0-100% to give methyl 8-[bis-(tert-butoxycarbonyl)amino]-6-hydroxy-5,6-dihydro-pyrazolo[5,1-a]isoquinoline-7-carboxylate (0.290 g).

Provenance & Evidence