Carbon Disulfide → tert-butyl (2S,4EZ)-4-(methoxy-imino)-2-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)-1-pyrrolidinecarboxylate

Participants

Reaction Steps

To a solution of tert-butyl (2S,4EZ)-2-(hydrazinocarbonyl)-4-(methoxyimino)-1-pyrrolidinecarboxylate (Intermediate 9, 2.86 mmoles; 780 mg) in ethanol (25 mL) at 0° C. was added carbon disulfide (6.86 mmoles; 522 mg) and potassium hydroxide (3 mmoles; 168 mg). The mixture was refluxed for 7 h. The solvent was evaporated and the residue re-dissolved in EtOAc and washed with NH4Cl sat and 10% NaHCO3 and brine. The organic layer was dried over Na2SO4 and evaporated to give the desired N-protected intermediate, tert-butyl (2S,4EZ)-4-(methoxyimino)-2-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)-1-pyrrolidine-carboxylate, as a yellowish oil (200 mg, 23%).

Provenance & Evidence