Diisopropylethylamine → tert-butyl 4-({[(1S)-1-(hydroxymethyl)-2-methoxy-2-oxoethyl]amino}carbonyl)-1H-indole-1-carboxylate

Participants

Reaction Steps

To a solution of methyl (2S)-2-amino-3-hydroxypropanoate hydrochloride (1.25 g), 1-(tert-butoxycarbonyl)-1H-indole-4-carboxylic acid (2.10 g) and N-ethyl-N-isopropyl-2-propanamine (2.94 mL) in DMF (25.0 mL) was added dropwise DPPA (1.91 mL) at 0° C. and the mixture was stirred at ambient temperature for 3 days. The resulting mixture was diluted with water (50.0 mL) and extracted with EtOAc (75 mL). The organic layer was washed successively with 1M HCl aqueous solution, saturated NaHCO3 aqueous solution. and brine, dried over anhydrous MgSO4, filtered and evaporated in vacuo. The residue was purified by silica gel column chromatography (chloroform:MeOH=99:1) to afford tert-butyl 4-({[(1S)-1-(hydroxymethyl)-2-methoxy-2-oxoethyl]amino}carbonyl)-1H-indole-1-carboxylate (2.12 g) as a colorless syrup.

Provenance & Evidence