Cesium carbonate → 1-(1-Benzhydryl-3-azetidinyl)-5-ethyl-4-nitro-1H-pyrazole-3-carboxamide

Participants

Reaction Conditions

Reaction Steps

1-Benzhydryl-3-azetidinyl methanesulfonate (8.03 g, 25.3 mmol, prepared according to the procedure in J. Org. Chem. 1991, 56, 6729-30) was added to a mixture of 3-ethyl-4-nitro-1H-pyrazole-5-carboxamide (4.64 g, 25.3 mmol, prepared using procedure in WO9849166) and cesium carbonate (8.24 g, 25.3 mmol) in MeCN (170 ml). The mixture was heated to 75° C. for 2 h and concentrated in vacuo. Water (200 ml) and EtOAc (200 ml) were added, and the mixture shaken. The insoluble solid at the interface was filtered off and dried to afford the title compound of preparation 52. The two layers of the filtrate were separated and the organic phase was dried (MgSO4), filtered and concentrated in vacuo. The residue was triturated with EtOAc (50 ml) and the resultant solid was filtered off, washed with hot DCM/MeOH (90:10, 50 ml) and dried to afford more of the title compound of preparation 52. The liquors and washings were combined and concentrated in vacuo. The residue was purified by column chromatography (DCM/MeOH, 98:2-95:5) to afford the title compound of preparation 51 plus a further small quantity of the title compound of preparation 52. The identity of the regioisomers was confirmed by nOe studies.

Provenance & Evidence