3-Cyclopentylpropionyl chloride → (2S)-2-tert-butoxy-2-(2-(3-cyclopentylpropanamido)-7-(8-fluoro-5-methylchroman-6-yl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)acetic acid

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Reaction Steps

A mixture of 2S)-2-(2-amino-7-(8-fluoro-5-methylchroman-6-yl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-(tert-butoxy)acetic acid (22 mg, 0.050 mmol), 3-cyclopentylpropanoyl chloride (8.79 mg, 0.055 mmol), Hunig's Base (0.026 mL, 0.15 mmol) in THF (2 mL) was stirred at rt for 16 h. It was then concentrated in vacuo and purified by prep HPLC (TFA/MeOH), the desired fractions were combined and adjusted to pH=6 using a few drops of 1N NaOH. The residue was then acidified to pH=4 using a few drops of 1N HCl. This solution was extracted with EtOAc. The organic phase was dried over MgSO4, filtered, and concentrated in vacuo to obtain (10 mg, 35%) of (2S)-2-tert-butoxy-2-(2-(3-cyclopentylpropanamido)-7-(8-fluoro-5-methylchroman-6-yl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)acetic acid as white solid.

Provenance & Evidence