Some Valenes of Benzannelated Five‐Membered Heteroarenes – Synthesis and NMR Spectra

Abstract

1,3‐Dipolar cycloadditions to 3‐benzvalenyI phenyl sulfones and elimination of phenylsulfinic acid afforded access to valenes such as 1 and 2. With a synthesis according to Paal and an Aldol condensation according to Hinsberg the benz‐valene‐annelated thiophenes 3 were obtained. The different formal arrangement of the double bonds in 1, on the one hand, and in 2, 3 on the other, give rise to clearly different 13C‐NMR chemical shifts of the bicyclobutane bridgehead atoms.

A new chemical method for synthesizing and recycling acyl coenzyme A thioesters

“…Compounds 1-3 were prepared by literature methods; a preliminary account of 4 has been reported. 10 The pKa values of the conjugate acids were determined by spectrophotometric titration, and the results in order of decreasing basicity are summarized in Table I, along with values for model compounds 2,3-dimethylquinoxaline (5) and quinoxaline (6).…”

Strained heterocyclic systems. 20. Basicities of bicyclic quinoxalines

“…Compounds 1-3 were prepared by literature methods; a preliminary account of 4 has been reported. 10 The pKa values of the conjugate acids were determined by spectrophotometric titration, and the results in order of decreasing basicity are summarized in Table I, along with values for model compounds 2,3-dimethylquinoxaline (5) and quinoxaline (6).…”