1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → Methyl 4-(4-(4-aminophenyl)-1-methyl-1H-pyrrole-2-carboxamido)-1-methyl-1H-imidazole-2-carboxylate

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Reaction Steps

0.3 gm of boc protected 6 (0.94 mmol, 1.2 eq) was dissolved in DMF (5 mL) to which 2.0 eq of EDCI and 2.5 eq of DMAP were added. The mixture was allowed to stir for 30 minutes after which commercially available methyl 4-amino-1-methyl-1H-imidazole-2-carboxylate (0.121 g, 0.79 mmol, 1.0 eq) was added. The reaction mixture was allowed to stir for a further 6 hour at which point TLC showed completion of reaction. The reaction was quenched by pouring it onto a mixture of ice/water mixture and the resulting mixture was extracted with ethyl acetate (3×150 mL). The combined extracts were sequentially washed saturated aqueous NaHCO3 (50 mL), water (50 mL), brine (50 mL) and finally dried over MgSO4. Excess ethyl acetate was evaporated by rotary evaporator under reduced pressure and the crude product (0.48 gm) was used for the boc deprotection step to afford 11. For boc deprotection, the crude intermediate was dissolved in a small volume of MeOH and 4M HCl in dioxane (5 mL) was added slowly to the stirring solution. The reaction mixture was stirred for 2 hours at which point TLC showed completion of reaction. Excess solvent was evaporated under vacuum to obtain a brown coloured solid (11). The solid product was subjected to flash chromatography (n-hexane/EtOAc 9:1) to give pure 11. Yield 0.35 gm, 81% over two steps.

Provenance & Evidence