Synthesis and Photophysical Properties of Alkynylated Pyrimidines by Site‐Selective Sonogashira Reactions of 2,4,5,6‐Tetrachloropyrimidine; First Synthesis of Tetraalkynyl‐pyrimidines

Abstract

A variety of novel alkynyl-substituted pyrimidines were prepared by the first site-selective Sonogashira cross-coupling reactions of 2,4,5,6-tetrachloropyrimidine. The products, di-, tri-, and tetraalkynyl-pyrimidines, exhibit fluorescence in the

The Solvatofluorochromism of 2,4,6‐Triarylpyrimidine Derivatives

“…The first of them employs condensation reactions from carbonyl and carbonyl‐masked compounds of already functionalized starting materials. The second approach, a more flexible one, is based on the use of palladium‐catalyzed cross‐coupling reactions of chloropyrimidines or pseudohalide derivatives .…”

Polycyclic Aromatic Hydrocarbons Bearing Polyethynyl Bridges: Synthesis, Photophysical Properties, and their Applications

“…Langer and co-workers' studies on the photophysical properties of pyrimidine core compounds (32, 36, and 66) (Figure 1) revealed their absorbance around 297-371 nm with the corresponding emission in the range of 395-470 nm. [77] Moreover, high Stokes shift was also observed with these compounds (32 a; 55 nm, 32 b; 41 nm, 32 c; 103 nm, 66 a; 115 nm, 66 b; 110 nm, 66 c; 136 nm, and 36; 108 nm).…”

“…Langer and co-workers' studies on the photophysical properties of pyrimidine core compounds (32, 36, and 66) (Figure 1) revealed their absorbance around 297-371 nm with the corresponding emission in the range of 395-470 nm. [77] Moreover, high Stokes shift was also observed with these compounds (32 a; 55 In 2017, Langer reported UV/PL studies of polyalkynylated naphthalene molecules (18, 67, 68 and 69) (Figure 2). [14a] The compounds 18 and 68 show absorption and emission wave-length in the range 300-400 and 400-450 nm, respectively.…”

“…[75] In 2000, Norman and co-workers reported the catalytic siteselective Sonogashira coupling at 2-position of 2,4-dihalopyridine 29 to give 30 in excellent yield (90%) in the presence of Pd(PPh 3 ) 2 Cl 2 /CuI (Scheme 10). [76] Later, Langer carried out site-selective alkynylation of chloro-pyrimidine compounds via the Pd(PPh 3 ) 2 Cl 2 (10 mol%)/ CuI (5 mol%) catalyzed Sonogashira coupling with aryl alkynes (Scheme 11) [77] using diisopropylamine as base and 1,4-dioxane as solvent at 55°C (32, 35, 36) (equation 1,3,4, Scheme 11) and 70°C (33) (equation 2, Scheme 11).…”

“…Later, Langer carried out site‐selective alkynylation of chloro‐pyrimidine compounds via the Pd(PPh 3 ) 2 Cl 2 (10 mol%)/CuI (5 mol%) catalyzed Sonogashira coupling with aryl alkynes (Scheme 11) [77] using diisopropylamine as base and 1,4‐dioxane as solvent at 55 °C ( 32 , 35 , 36 ) (equation 1,3,4, Scheme 11) and 70 °C ( 33 ) (equation 2, Scheme 11).…”