Hydrochloric Acid → (1S,2R,4S)-4-(cyclopropanesulfonamido)-2-ethylcyclopentanecarboxylic acid

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Reaction Steps

To a flask containing (1S,2R,4S)-ethyl 4-(cyclopropanesulfonamido)-2-ethylcyclopentane-carboxylate (11.1 g, 38.4 mmol, prepared using K from Preparation #Y.1, cyclopropanesulfonyl chloride and TEA, AA [Table 2, Method 1, Rt=9.5 min, or =negative]) was added aqueous NaOH (1 N, 210 mL, 210 mmol). After stirring at ambient temperature for about 8 h, the reaction was acidified to about pH 1 using 6 N aqueous HCl and extracted with DCM (3×150 mL). The combined organic layers were washed with brine, dried over anhydrous MgSO4, filtered, and concd under reduced pressure to give (1S,2R,4S)-4-(cyclopropanesulfonamido)-2-ethylcyclopentanecarboxylic acid with 25 mol % DCM as an excipient (10.7 g, 99%): LC/MS (Table 1, Method a) Rt=1.71 min; MS m/z: 260 (M−H)−.

Provenance & Evidence