1-Bromo-3-methylbutane → Ethyl 1-isopentyl-4-nitro-1H-pyrrole-2-carboxylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Ethyl 4-nitro-1H-pyrrole-2-carboxylate (2.022 g, 10.983 mmol; see Example 1, step (i) above) was dissolved in DMF (30 mL, dry) to which potassium (0.569 g, 14.552 mmol) was added with stirring under nitrogen. The reaction mixture was heated at 100° C. for 1 h and then the temperature was allowed to reach 50° C. Isoamyl bromide (2.498 g, 16.538 mmol) was then added, followed by KI (2.197 g, 14.552 mmol). The temperature was raised to 100° C. and stirring continued for 5 h, after which time the temperature was allowed to return to room temperature. The reaction mixture was then stirred overnight, following which the solvent was removed under reduced pressure at 50° C. The crude product was dissolved in DCM and the salt extracted with water. The organic extract was dried over MgSO4, filtered and the solvent removed under reduced pressure at 30° C. The crude product obtained was chromatographed over silica gel using 1/2 n-hexane/DCM as eluant. Material with Rf=0.3 was collected and the solvent was removed under reduced pressure to give white crystalline material (2.377 g, 85% yield). M.p. 46-47° C. (Lit. m.p. 46-47° C.).

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