Nitrogen → Methyl 2-(5-bromothiophen-2-yl)acetate

Beteiligte Stoffe

Reaktionsschritte

(The following reaction is carried out in an anhydrous N2 atmosphere.) Dissolve thiophene-2-yl-acetic acid methyl ester (42) (2.0 g, 12.8 mmol) in anhydrous chloroform (9.0 mL) and glacial acetic acid (9.0 mL), add N-bromosuccinimide (2.3 g, 13.0 mmol) in portions and stir the mixture for 3 d at rt. Add water to the reaction mixture, separate layers and extract the aqu. layer with dichloromethane. Wash combined organic layer several times with a 1 M aqu. NaOH and water and once with brine and dry it with Na2SO4. Purify the crude product by preparative radial chromatography (CyH/EtOAc 5+1] to obtain (5-bromo-thiophen-2-yl)-acetic acid methyl ester (43) as a yellow oil (2.46 g, 81%) which is used without any further purification. 1H NMR (400 MHz, CDCl3): 3.71 (s, 3H); 3.75 (s, 2H); 6.67 (d, 1H, J=3.8 Hz); 6.88 (d, 1H, J=3.8 Hz).

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