Bioorthogonal Ligation and Cleavage by Reactions of Chloroquinoxalines with ortho‐Dithiophenols

Abstract

A bioorthogonal ligation and cleavage method via reactions of chloroquinoxalines (CQ) and ortho‐dithiophenols (DT) is presented. Double nucleophilic substitutions of ortho‐dithiophenols to chloroquinoxalines provide conjugates containing tetracyclic benzo[5,6][1,4]dithiino[2,3‐b]quinoxaline with strong built‐in fluorescence together with release of the other functional molecules. Three cleavable linkers were designed and successfully used in release of the molecules containing biotin from the protein conjugates. The CQ‐DT bioorthogonal reactions can be applied for the bioorthogonal ligations, bioorthogonal cleavages, and trans‐tagging of proteins, and show advantages of readily accessible unnatural orthogonal groups, appealing reaction kinetics (k2≈1.3 m−1 s−1), excellent biocompatibility of orthogonal groups, and high stability of conjugates. This complements previous bioorthogonal reactions and is a new route for protein‐fishing applications and in‐gel fluorescence analysis.

Unleashing the Power of Bond Cleavage Chemistry in Living Systems

“… 114 The bioorthogonal cleavage chemistry used in this work was based on the deprotection of silyl groups from phenols with a fluoro reagent 114 ( Figure 6 , entry 6). In addition, other BCRs, such as Staudinger reduction 115 and nucleophilic substitution reactions, 116 may also hold the potential for developing internal cleavable linkers for the on-demand release of bioconjugates ( Figure 6 , entries 7 and 8).…”

“…114 The bioorthogonal cleavage used in this work was based on the deprotection of silyl groups from phenols with a fluoro reagent 114 (Figure 6, entry 6). In addition, other BCRs, such as Staudinger reduction 115 and nucleophilic substitution reactions, 116 may also hold the potential for developing internal cleavable linkers for the ondemand release of bioconjugates (Figure 6, entries 7 and 8). Since transition metals have mainly been applied on smaller protecting groups (e.g., allylic or propargyl moieties), there are limited sites that are able to be remodeled as internal cleavable linkers.…”

Recent Progress of Bioorthogonal Chemistry in China

“…他们通过调节芳香环上氟原 子的取代数量对叠氮的亲电性进行调节, 从而优化反应 速率(50 L•mol -1 •s -1 ), 并成功地将优化后的施陶丁格反 应应用于核酸及蛋白质的荧光标记. Small molecule-mediated bioorthogonal ligation reactions [37][38][40][41] 而付华课题组 [41] 我国学者在国际上首次提出"生物正交剪切反应 (bioorthogonal cleavage reaction)"这一概念 [10,[12][13][14] 5 Metal-mediated bioorthogonal cleavage reactions [42][43] 3.2 光介导的剪切反应 在此之前, 以紫外光触发邻硝基苯脱除反应为代表 的"光剪切"反应已被广泛用于生物分子的光控激活 [44] . 而最近我国学者对光催化或辐射触发的剪切反应进行 了研究, 开发了新型生物正交剪切化学.…”

Bioorthogonal Ligations and Cleavages in Chemical Biology

“…Double nucleophilic substitutions of DT to CQ provided the conjugates containing tetracyclic benzo[5,6][1,4]dithiino[2,3‐ b ]quinoxalines with strong built‐in fluorescence with releasing the other active molecules (Figure ). The CQ‐DT bioorthogonal reactions were used in the bioorthogonal ligations, bioorthogonal cleavages and simultaneous bioorthogonal ligations and cleavages, and the method exhibits some advantages including the readily accessible unnatural orthogonal groups, the appealing reaction kinetics ( k 2 ≈1.3 M −1 s −1 ), excellent biocompatibility of the orthogonal groups and high stability of the conjugates …”

“…The CQ-DT bioorthogonal reactions were used in the bioorthogonal ligations, bioorthogonal cleavages and simultaneous bioorthogonal ligations and cleavages, and the method exhibits some advantages including the readily accessible unnatural orthogonal groups, the appealing reaction kinetics (k 2 � 1.3 M À 1 s À 1 ), excellent biocompatibility of the orthogonal groups and high stability of the conjugates. [165]…”