Regioselective Lipase‐Catalyzed Synthesis of Diester Crowns. New Asymmetric Macrocycles Containing a 1,3‐Bis(1H‐pyrazol‐1‐yl)propane Unit.

摘要: Abstract Regioselective lipase catalyzed intramolecular transesterification of dipyrazolic tetraester 1 with di-, tri- and tetraethyleneglycol afforded symmetric and, in smaller amounts, asymmetric diester crowns including a 1,3-bis(1 H -pyrazol-1-yl)propane unit. Their structures have been unequivocally elucidated after their 13 C NMR spectra INEPT experiments.