SummaryThe one-pot cyclization of 5-hexynoic acid to produce 3-alkoxy-2-cyclohexenones proceeds in good yields (58–90%). 3-Hexynoic acid was converted to its acyl chloride with the aid of oxalyl chloride and was cyclized to 3-chloro-2-cyclohexenone upon addition of indium(III) chloride. Subsequent addition of alcohol nucleophiles led to the desired 3-alkoxy-2-cyclohexenones.

A simple preparation of ethyl 2,5‐dimethylfuran‐3‐carboxylate (3), 2,5‐dimethylfuran‐3,4‐dicarboxylic acid (4), and diethyl 2,5‐dimethylfuran‐3,4‐dicarboxylate (5) by treatment of diethyl 2,3‐diacetylsuccinate (2) with aqueous HCl is reported. The reaction is performed under organic solvent free conditions from a readily available cheap starting material. J. Heterocyclic Chem., (2009).

Furan derivatives R 0060A Simple Preparation of Ethyl 2,5-Dimethylfuran-3-carboxylate and 2,5-Dimethylfuran-3,4-dicarboxylic Acid from Diethyl 2,3-Diacetylsuccinate. -The products can be easily prepared by thermal or microwave-promoted Paal-Knorr cyclization. The outcome of the reaction can be simply influenced by adjusting the HCl concentration. Diester (II) is only obtained under microwave irradiation.

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