40564-75-8Relevant academic research and scientific papers
Unexpected pyrylium to pyrylium domino transformation. Synthesis of pyrano[3,4-c]pyran-7-ium cation and its recyclization to 2,7-naphthyridine derivative
Suzdalev, Konstantin F.,Krachkovskaya, Alina V.,Kletskii, Mikhail E.,Burov, Oleg N.,Tatarov, Artem V.,Kurbatov, Sergey V.
, p. 156 - 160 (2017)
[Figure not available: see fulltext.]4-Ethyl-3-formyl-2,6-diphenylpyrylium perchlorate was obtained from 2,6-diphenylpyrylium perchlorate in three steps. Its reaction with triethyl orthoformate was accompanied by rearrangement of the initial pyrylium ring and led to pyrano[3,4-c]pyran-7-ium perchlorate system through a domino process involving ethanol addition-elimination. A plausible mechanism of the reaction is suggested on the basis of DFT quantum-chemical calculations. Reaction of the obtained pyrano[3,4-c]pyran-7-ium perchlorate with ammonium acetate led to a 2,7-naphthyridine derivative without a skeletal rearrangement.
Synthesis and Reactions of 2,6-Diphenyl-4-(trimethylsilyl)-4H-thiopyran
Chen, Chin H.,Doney, Jeffrey J.,Reynolds, George A.
, p. 680 - 684 (2007/10/02)
The title compound 3 was synthesized by trimethylsilyl chloride quenching of 2,6-diphenyl-4-lithio-4H-thiopyran (7), which was obtained by direct lithiation (n-BuLi) of either the 4H-thiopyran 10 or the 2H isomer 6.Compound 6 was readily prepared in one step from the reaction of 2,6-diphenyl-4-hydroxy-4H-thiopyran (5) with NCS in 74percent yield.Compound 3 was metalated to give 12 in 80-85percent yield by using a combination of n-BuLi and t-BuOK in THF at an internal temperature slightly below -20 deg C.The successful reaction of 12 with a variety of ketones and aldehydes provides an alternative synthesis of the Δ4-2,6-diphenyl-4H-thiopyrans 16.The scope and limitation of this Peterson-type reaction of 12 is compared with those of the corresponding Wittig-Horner reagent 2.
