Diisopropylethylamine → cis(+/-)Tert-butyl-3-azido-4-{[(3,4-dichloro-5-methyl-1h-pyrrol-2-yl)carbonyl]amino}piperidine-1-carboxylate

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Reaction Steps

Crude tert-butyl-4-amino-3-azidopiperidine-1-carboxylate (Intermediate 270, 3.3 mmol) was dissolved in anhydrous CH2Cl2 (10 ml) and DIEA (1.27 g; 1.6 ml; 9.9 mmol; 3 eq.). The solution was cooled to 0 C and 3,4-dichloro-5-methyl-1H-pyrrole-2-carbonyl chloride (736 mg; 3.5 mmol; 1.05 eq.) was added. The reaction was complete within 30 minutes. Dilute with CH2Cl2 and wash with H2O (×2), brine and dried over Na2SO4. Filter and concentrate. Purify by flash column chromatography (0-60% EtOAc/hexanes). Isolation gave 967 mg in 69% yield over the two-step sequence. LC/MS (ES−)[(M−H)+]: 415, 417 for C16H22Cl2N6O3.

Provenance & Evidence