Cesium carbonate → HCID 66665662, compound

Participants

Reaction Steps

To a microwave vial was added 2-methyl-6,7-diphenyl-1,2,3,4-tetrahydro-1,8-naphthyridine (step 2) (345 mg, 1.148 mmol) in NMP (1 ml) followed by ethyl 7-bromoheptanoate (0.671 ml, 3.45 mmol) and cesium carbonate (748 mg, 2.297 mmol). The resulting mixture was heated using microwave radiation at 160° C. for 2 h. Ethyl-7-bromoheptanoate (0.671 ml, 3.45 mmol) was added and heating continued for a further 2 h. The reaction mixture was partitioned between EtOAc and water and the organic portion was washed with brine, dried over MgSO4, filtered and concentrated in vacuo. Purification of the crude product by chromatography on silica eluting with 0-20% EtOAc in iso-hexane afforded a yellow oil which was loaded onto a Isolute™ SCX-2 cartridge and eluted with MeOH followed by 2M NH3 in MeOH. The methanolic ammonia fractions were concentrated in vacuo to afford racemate ethyl 7-(2-methyl-6,7-diphenyl-3,4-dihydro-1,8-naphthyridin-1(2H)-yl)heptanoate. Chiral separation of the mixture using Supercritical Fluid Chromatography afforded the individual enantiomers.

Provenance & Evidence