2-methylpropan-2-aminium (Z)-4-(5-chloro-1-methyl-3-(pyridin-2-yl)-1H-pyrazol-4-yl)-4-(4-chloro-2-methylphenyl)but-3-enoate → 2-methylpropan-2-aminium 4-(5-chloro-1-methyl-3-(pyridin-2-yl)-1H-pyrazol-4-yl)-4-(4-chloro-2-methylphenyl)butanoate

Participants

Reaction Conditions

Reaction Steps

Chloro(1,5-cyclooctadiene)rhodium(I) dimer (0.068 g, 0.277 mmol), (S)-1-[(RP)-2-[Bis(4-methoxy-3,5-dimethylphenyl)phosphino]ferrocenyl}ethyldi-tert-butylphosphine (0.182 g, 0.277 mmol), and 2-methylpropan-2-aminium (Z)-4-(5-chloro-1-methyl-3-(pyridin-2-yl)-1H-pyrazol-4-yl)-4-(4-chloro-2-methylphenyl)but-3-enoate (13.17 g, 27.7 mmol) were combined in a 250 mL stainless steel pressure bottle. A stir bar was added, and the system was degassed with 20 psi argon, and then vented. Argon-degassed MeOH (131 mL) was added against an argon stream by cannula, and the vessel was again sealed and degassed with argon. The system was shaken for about 30 min at about 50° C. The reactor was pressurized to 55 psi with hydrogen shaken at about 70° C. for about 14.5 h. The mixture was filtered through glass wool and concentrated in vacuo to give 2-methylpropan-2-aminium 4-(5-chloro-1-methyl-3-(pyridin-2-yl)-1H-pyrazol-4-yl)-4-(4-chloro-2-methylphenyl)butanoate (13.2 g, 100%) as a foam. 4-(5-Chloro-1-methyl-3-(pyridin-2-yl)-1H-pyrazol-4-yl)-4-(4-chloro-2-methylphenyl)butanoate (14.4 g, 30.2 mmol) in DCM (250 mL) and was washed with 20% citric acid (2×300 mL). The combined aqueous layers were extracted with DCM (250 mL). The combined organic layers were washed with H2O (400 mL). The aqueous layer was extracted with EtOAc (250 mL). The combined organic layers were concentrated in vacuo. The residue was dissolved in THF (150 mL) and loaded on a silica gel pad (600 g) then eluted with THF. The product containing fractions were concentrated in vacuo. The material was dissolved in 2-methyltetrahydrofuran (500 mL) then washed with 20% citric acid (400 mL), H2O (3×400 mL) and brine (400 mL). The organic layer was dried over Na2SO4, filtered and concentrated in vacuo to give 4-(5-chloro-1-methyl-3-(pyridin-2-yl)-1H-pyrazol-4-yl)-4-(4-chloro-2-methylphenyl)butanoic acid (12.2 g, 100%): LC-MS (Table 1, Method g) Rt=2.37 min, m/z 404/406 (M+H)+; 1H-NMR (DMSO, Bruker 400 MHz) δ 11.98 (s, 1H), 8.60-8.56 (m, 1H), 7.86-7.79 (m, 2H), 7.39 (d, J=8.4 Hz, 1H), 7.36-7.28 (m, 1H), 7.19-7.14 (m, 1H), 7.13-7.11 (m, 1H), 5.30-5.24 (m, 1H), 3.83 (s, 3H), 2.45-2.32 (m, 1H), 2.29-2.14 (m, 3H), 2.08 (s, 3H).

Provenance & Evidence