Author's Organization：Central Research Laboratory, Daiichi Seiyaku Co., Ltd. Central Research Laboratory, Daiichi Seiyaku Co., Ltd. Central Research Laboratory, Daiichi Seiyaku Co., Ltd. Central Research Laboratory, Daiichi Seiyaku Co., Ltd.
Condensation of I with several dienophiles caused three types of reaction, i.e. reaction A, B, and C; reaction B and C afforded 3-pyridinol derivatives. A likely mechanism of these reactions are considered as Diels-Alder's condensation of I with dienophiles and subsequent aromatization to pyridine nuclei.
