Studies of pyrans and related compounds

A Versatile AIE Fluorogen with Selective Reactivity to Primary Amines for Monitoring Amination, Protein Labeling and Mitochondrial Staining

“…Hereby, CMVMN may follow a reaction path similar to typical chromones. 15,16 Later, density functional theory calculation was carried out and the results were in line with the experimental results. The energy profile for the reaction pathway of CMVMN with PA was shown in Scheme 2.…”

“…According to the previous report, the 1 H NMR spectra of enamines generated from chromones and primary amines showed a characteristic broad signal at δ 9-12, which attributed to the resonance of an NH group forming a strong intermolecular hydrogen bond. 15 Accordingly, a new broad peak at δ 10.8 emerged in the 1 H NMR spectra of CMVMN after addition of PA and the signal was intensified when more PA was added (Figure S13). Meanwhile, the original conjugated structure of CMVMN was destroyed to result in a decreased deshielding effect on the surrounding hydrogen atoms.…”

“…16 Besides, the discovery of epicocconone, which shows a relatively high reactivity to primary amines and is capable of staining proteins in the aqueous media, reminds us the importance of rational molecular design. 17 So even though none of the reported chromone derivatives can realize fast, selective bioconjugation for primary amines at room temperature, 15,16,18 we believe that their selectivity can be enhanced through molecular engineering. Specifically, when an electron withdrawing group is introduced to the α position of chromone, the obtained new compound is activated and may show a good affinity and selectivity towards primary amines.…”

“…This possibly induces a high affinity of chromone towards primary amines. 15 The introduction of a methyl group in α position of the carbonyl group of chromone can further affect its reaction with secondary amines to result in enhanced selectivity towards primary amines. 16 Besides, the discovery of epicocconone, which shows a relatively high reactivity to primary amines and is capable of staining proteins in the aqueous media, reminds us the importance of rational molecular design.…”

Reactions of 2‐Methylchromones with Cyanoacetamides and Ethyl Cyanoacetate. Synthesis of 6‐(2‐Hydroxyaryl)‐4‐methyl‐2‐oxo‐1,2‐dihydropyridine‐3‐carbonitriles and 7‐Hydroxy‐6‐imino‐9‐methyl‐6H‐benzo[c]chromene‐8‐carbonitriles

“…Although 2‐methylchromones 1 constitute a small family of naturally occurring compounds, their synthesis and transformations into other biologically active compounds have been exploited . It is known that the pyrone ring of 1 is susceptible to ring opening under the action of N ‐nucleophiles such as amines , hydrazines , hydroxylamine , and thiourea . However, only a handful of papers describing some examples of reactions with C ‐nucleophiles is present in the literature.…”