Hydrochloric Acid → 3-ethyl-4-(6-tosyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazin-1-yl)cyclopentanol

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Reaction Steps

A scalemic mixture enriched in 1-((1S,2R,4R)-4-(tert-butyldimethylsilyloxy)-2-ethylcyclopentyl)-6-tosyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazine (1.55 g, 2.87 mmol) was suspended in ethanol (30 mL). Concentrated HCl (0.3 mL, 3.65 mmol) was added dropwise. After about 1 h., the suspension was sonicated until all solid went into solution. EtOAc (250 mL) was added and the organics were washed with saturated aqueous NaHCO3 (2×30 mL) and brine (30 mL), dried over anhydrous MgSO4, filtered, and concd under reduce pressure. The residue was purified using silica gel chromatography eluting with 30-80% EtOAc in DCM to give a scalemic mixture enriched in (1R,3R,4S)-3-ethyl-4-(6-tosyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazin-1-yl)cyclopentanol (1.09 g, 90%): LC/MS (Table 1, Method b) Rt=1.99 min; MS m/z: 426 (M+H)+.

Provenance & Evidence