Cl[S:2]([CH2:5][C@H:6]([CH3:17])[C:7]([O:9][CH2:10][C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)=[O:8])(=[O:4])=[O:3].[NH:18]1[CH2:23][CH2:22][CH2:21][CH2:20][CH2:19]1>C(Cl)Cl>[N:18]1([S:2]([CH2:5][C@H:6]([CH3:17])[C:7]([O:9][CH2:10][C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)=[O:8])(=[O:4])=[O:3])[CH2:23][CH2:22][CH2:21][CH2:20][CH2:19]1A 100 mL round bottom flask equipped with magnetic stir bar was charged with 1 g benzyl 3-chlorosulfonyl-2(R)-methylpropionate from Example 3 in 25 mL CH2Cl2. The solution was cooled to 0° C. and 4 mL of piperdine was slowly added. The reaction was stirred 1 hour then concentrated in vacuo. The residue was partioned between ethyl acetate and water. The organic phase was washed with brine, dried, and concentrated in vacuo to give 1 g of benzyl 3-(1-piperidinyl)sulfonyl-2(R)-methylpropionate suitable for use without further purification. Part B: 3-(1-piperidinyl)sulfonyl-2(R)-methylpropionic acid A 100 mL Fisher/Porter vessel was charged with 1 g of benzyl 3-(1-piperidinyl)sulfonyl-2(R)-methylpropionate 30 mL MeOH and a catalytic amount of 10% Pd—C. The reaction was hydrogenated at 50 psi for 3 hours. After filtration through Celite and concentration in vacuo of 3-(1-piperidinyl)sulfonyl-2(R)-methylpropionic acid was isolated in quantitive yield.
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