Tin tetrachloride → 2-[(3-Methyl-2-thienyl)carbonyl-1H-pyrrol-1-yl]-1H-isoindole-1,3(2H)dion

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution consisting of 3-methyl-2-thiophenecarboxylic acid (21.0 g) in dry DCM (1.5 l) was added oxalyl chloride (21.0 ml) at room temperature under nitrogen. After stirring for 1 hour at room temperature, the reaction mixture was cooled to -10° C. and tin (IV) chloride (17.3 ml) was added. The resulting solution was stirred for 10 minutes (-10° C.) at which time 2-(1H-pyrrol-1-yl)-1H-isoindole-1,3(2H)dione (31.3 g) was added in three portions. After stirring for 1 hour in the cooling bath, the reaction mixture was poured into cold water and the layers separated. The organic phase was washed twice with 5% HCl (aq.) and dried (MgSO4). Filtration and concentration gave the crude product. Purification via preparative HPLC (silica gel, DCM) afforded 12.5 g of the product as a solid, m.p. 221°-223° C.

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