Collect. Czech. Chem. Commun. 1992, 57, 546-555

Electrophilic 3,5-Substitution of 2,4,4,6-Tetraphenyl-4H-pyran and Some of Its 1-Heteroanalogues

Marián Schwarz, Pavel Šebek and Josef Kuthan

Department of Organic Chemistry, Institute of Chemical Technology, 166 28 Prague 6


The reaction of dibromine with the heterocycles I-IV gives corresponding 3,5-dibromo derivatives, while the less selective reactions with dichlorine afforded 3,5-dichloro derivative XII only in the case of 4H-thiopyran IV and trichloro derivative of the probable formula XIII in the case of 1,4-dihydropyridine II. Dichloro derivative IX was obtained on reaction of phosphorus pentachloride with substrate I. Nitration of compounds I-IV gives 3,5-dinitroderivatives XV-XVIII, but mononitro derivatives XIX and XX were also obtained. Iodination of compounds II-IV with di-iodine was unsuccessful.