1666-86-0Relevant articles and documents
Base-Mediated Three-Component Tandem Reactions for the Synthesis of Multisubstituted Pyrimidines
Liu, Dongqing,Guo, Wei,Wu, Wanqing,Jiang, Huanfeng
, p. 13609 - 13616 (2017)
A base-mediated three-component tandem reaction for the synthesis of multisubstituted pyrimidines from amidines, aryl alkynes, and aldehydes in a one-pot manner has been developed. Advantages of this transformation include being transition-metal-free, high efficiency, available starting materials, and being environmentally friendly.
Oxidative Coupling with Zr(IV) Supported by a Noninnocent Anthracene-Based Ligand: Application to the Catalytic Cotrimerization of Alkynes and Nitriles to Pyrimidines
Low, Choon Heng,Rosenberg, Jeffrey N.,Lopez, Marco A.,Agapie, Theodor
, p. 11906 - 11910 (2018)
We report the synthesis and reactivity of Zr complexes supported by a 9,10-anthracenediyl-linked bisphenoxide ligand, L. ZrIVLBn2 (1) undergoes facile photolytic reduction with concomitant formation of bibenzyl and ZrIVL(THF)3 (2), which displays a two-electron reduced anthracene moiety. Leveraging ligand-stored reducing equivalents, 2 promotes the oxidative coupling of internal and terminal alkynes to isolable zirconacyclopentadiene complexes, demonstrating the reversible utilization of anthracene as a redox reservoir. With diphenylacetylene under CO, cyclopentadienone is formed stoichiometrically. 2 is competent for the catalytic formation of pyrimidines from alkynes and nitriles. Mechanistic studies suggest that selectivity for pyrimidine originates from preferred formation of an azazirconacyclopentadiene intermediate, which reacts preferentially with nitriles over alkynes.
Metal-free cascade synthesis of unsymmetrical 2-aminopyrimidines from imidazolate enaminones
Cui, Xue,Li, Youbin,Ma, Jianting,Wang, Xuesong,Xu, Junyu,Zeng, Tingting
, p. 24247 - 24253 (2021/07/29)
A convenient metal-free synthesis of unsymmetrical 2-aminopyrimidines from imidazolate enaminones has been developed. In this procedure, various structural 2-aminopyrimidines, as well as 4,5-dihydroisoxazol-5-ols and pyrazoles were synthesized in moderate to excellent yields. A plausible mechanism was also proposed for the cascade reaction. This method represents an effective strategy towards the synthesis of unsymmetrical 2-aminopyrimidines.
Bioinspired Radical-Mediated Transition-Metal-Free Synthesis of N-Heterocycles under Visible Light
K. Bains, Amreen,Ankit, Yadav,Adhikari, Debashis
, p. 324 - 329 (2020/11/30)
A redox-active iminoquinone motif connected with π-delocalized pyrene core has been reported that can perform efficient two-electron oxidation of a class of substrates. The design of the molecule was inspired by the organic redox cofactor topaquinone (TPQ), which executes amine oxidation in the enzyme, copper amine oxidase. Easy oxidation of both primary and secondary alcohols happened in the presence of catalytic KOtBu, which could reduce the ligand backbone to its iminosemiquinonate form under photoinduced conditions. Moreover, this easy oxidation of alcohols under aerobic condition could be elegantly extended to multi-component, one-pot coupling for the synthesis of quinoline and pyrimidine. This organocatalytic approach is very mild (70 °C, 8 h) compared to a multitude of transition-metal catalysts that have been used to prepare these heterocycles. A detailed mechanistic study proves the intermediacy of the iminosemiquinonate-type radical and a critical hydrogen atom transfer step to be involved in the dehydrogenation reaction.