... J. Heterocyclic Chem., 36, 979 (1999). ... 4-40;JHa.Hc=1.47;JHb.Hc = He O' He O" - f7NRI Ha^V^^I C02R He OH He OH He OH Hb^J^+A^COjR НьЛЛу О' О" .C02R The uv ... Chemical shifts are quoted in parts per million (S) downfield from the internal tetramethylsilane reference. ...