Hydrochloric Acid → 2-((1R,2R)-1-amino-2-hydroxypropyl)-5-(3-(cyclopropylamino)-6-fluoro-2-methylquinoxalin-5-yl)-1H-pyrrole-3-carboxylic acid

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Reaction Conditions

Reaction Steps

The yellow foam (352b) (184.5 mg) in 1,4-dioxane (6.0 mL) was treated with 1.0 M aq. LiOH (3.0 mL, 3.0 mmol). The mixture was heated at 100° C. for 16 h. The mixture was lyophilized to give a yellow solid containing m/z (ESI, +ve) 614.1 (M+H). The yellow solid was dissolved in 1 mL of dioxane and treated with a solution of 4 M HCl in 1,4-dioxane (5 mL) with a few drops of water added to aid solubility. The mixture was stirred at RT for 4 h, after which time bis-deprotection was observed by LC-MS. The mixture was lyophilized to give 2-((1R,2R)-1-amino-2-hydroxypropyl)-5-(3-(cyclopropylamino)-6-fluoro-2-methylquinoxalin-5-yl)-1H-pyrrole-3-carboxylic acid (352c) as a brown solid. A solution of the 2-((1R,2R)-1-amino-2-hydroxypropyl)-5-(3-(cyclopropylamino)-6-fluoro-2-methylquinoxalin-5-yl)-1H-pyrrole-3-carboxylic acid (352c) in DMF (3.0 mL) was treated with TEA (0.20 mL, 1.44 mmol) followed by PyBOP (NovaBiochem) (300 mg, 0.57 mmol). The mixture was stirred at RT for 16 h. The mixture was concentrated, dissolved in DMSO (5.0 mL), and purified by preparative HPLC (Gradient: 10-100% MeCN in H2O, modified with 0.1% TFA) to give (R)-2-(3-(cyclopropylamino)-6-fluoro-2-methylquinoxalin-5-yl)-6-((R)-1-hydroxyethyl)-5,6-dihydropyrrolo[3,4-b]pyrrol-4(1H)-one bis(2,2,2-trifluoroacetate) (352) (54 mg, 0.089 mmol) as a red gum. LC-MS m/z 382.1, [M+H]+; 19F NMR (DMSO-d6; 376 MHz): δ −108.08 (s, 1F), −74.95 (s, 6F).

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