Synthesis of tetrahydropyrimidinium salts and their in situ catalytic activities towards the Buchwald--Hartwig amination reaction under microwave irradiation
asymmetrical substituted tetrahydropyrimidiniumsalts and different kinds of bridged bis-tetrahydropyrimidinium salts were prepared through the quaterization of tetrahydropyrimidine or the dehydrogenation of hexahydropyrimidine. They were characterized and used as NHC precursors in the palladium catalyzed Buchwald--Hartwig amination reaction. The in situ formed catalyticsystem Pd(OAc)2/tetrahydropyrimidinium
investigated the fixation of CO2 by several amidines in solution and found that simple monocyclic amidines fixed CO2 under dry conditions to quantitatively afford the corresponding bicarbonatesthrough hydrolysis of the zwitterionic adducts by adventitious water. In contrast, linear amidines did not form the bicarbonates under the same conditions, while 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) could not
A novel, efficientsynthesis of cyclic carbonates from the reaction of epoxides and gaseous CO2 under mild conditions (1 atm, rt to 45 °C) was achieved in reasonable yields (65–83%) by using N-methyltetrahydropyrimidine (MTHP) that facilitated efficient delivery of CO2 from the gas phase to the reaction system.
Synthesis of polymers having zwitterionic structure via the radical polymerization of 4-vinylphenyl isothiocyanate/cyclic amidine adduct
作者:Akira Yamauchi、Kozo Matsumoto、Takeshi Endo
DOI:10.1002/pola.29203
日期:2018.10.15
A zwitterionic monomer (4‐vinylphenyl isothiocyanate [VPI]‐1,2‐dimetyl‐1,4,5,6,‐tetrahydropirimidine [DMTHP]) was synthesized by the reaction of VPI and a cyclic amidine DMTHP. A radical polymerization of VPI‐DMTHP was carried out using 2,2′‐azobis(2,4‐dimethyl‐4‐methoxy)valeronitrile (V‐70) as an initiator to give poly(VPI‐DMTHP). The obtained poly(VPI‐DMTHP) was not soluble in any of the investigated