Nitrogen → Thieno[2,3-b]pyridine-5,6-dicarboxylic acid anhydride

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Reaction Steps

Acetic anhydride (37.4 g, 0.366 mol) is added to a stirred suspension of thieno[2,3-b]pyridine-5,6-dicarboxylic acid (21.52 g, 0.096 mol) in dimethoxyethane (175 mL) in an inert N2 atmosphere. Upon addition of pyridine (16.78 g, 0.21 mol) at room temperature an exotherm to 45° C. is observed and a homogeneous solution results. The reaction mixture is then stirred at room temperature and the resulting solid filtered off, washed with ether and air dried to give 14.8 g (75%) of thieno[2,3-b]pyridine-5,6-dicarboxylic acid anhydride.

Provenance & Evidence