ChemInform Abstract: Alkyl and Aryl 4,5‐Dichloro‐6‐oxopyridazin‐1(6H)‐carboxylates: A Practical Alternative to Chloroformates for the Synthesis of Symmetric and Asymmetric Carbonates.

Abstract

Symmetric and asymmetric carbonates were synthesized by using alkyl or aryl 4,5-dichloro-6-oxopyridazin-1(6 H )-carboxylates. Five aryl 4,5-dichloro-6-oxopyridazin-1(6 H )-carboxylates were converted into the corresponding diaryl carbonates in good to excellent yields by treatment with potassium carbonate in refluxing THF. When the 4,5-dichloro-6-oxopyridazin-1(6 H )-carboxylates were treated with aliphatic or aromatic alcohols in the presence of potassium tert -butoxide in toluene at room temperature, they gave the corresponding symmetric or asymmetric carbonates in moderate to excellent yields. Alkyl and aryl 4,5-dichloro-6-oxopyridazin-1(6 H )-carboxylates are therefore efficient, stable, and ecofriendly alternatives to chloroformates.