No abstract

Sulfuryl fluoride, SO2F2, has been found to derivatize phenols in all kinds of environments, even those in highly functional molecules. We now report that a solid fluorosulfuryl imidazolium triflate salt delivers the same “F−SO2+” fragment to Nu−H acceptor groups in the substrates. However, this triflate salt is a far more reactive fluorosulfurylating agent than SO2F2 and displays selectivity preferences of its own. Moreover, the new azolium triflate reagent reacts once with primary amines and anilines before the reaction stops. On the other hand, with triethylamine and two equivalents of the “F−SO2+” donor present, it proceeds on to the bis(fluorosulfuryl)imides in good yield—two important conversions that we have never seen with sulfuryl fluoride as the electrophile.

Protein glycosylation is the most complex post‐translational modification process. More than 50 % of human cells proteins are glycosylated, whereas bacteria such as E. coli do not have this modification machinery. Indeed, the carbohydrate residues in natural proteins affect their folding, immunogenicity, and stability toward proteases, besides controlling biological properties and activities. It is therefore important to introduce such structural modification in bioengineered proteins lacking the presence of carbohydrate residues. This is not trivial as it requires reagents and conditions compatible with the protein's stability and reactivity. This work reports on the introduction of lactose moieties in two natural proteins, namely ubiquitin (Ub) and l‐asparaginase II (ANSII). The synthetic route employed is based on the sulfur(VI) fluoride exchange (SuFEx) coupling of a lactose tethered arylfluorosulfate (Lact‐Ar‐OSO2F) with the ϵ‐NH2 group of lysine residues of the proteins. This metal‐free click SuFEx reaction relies on the properties of the fluorosulfate employed, which is easily prepared in multigram scale from available precursors and reacts chemoselectively with the ϵ‐NH2 group of lysine residues under mild conditions. Thus, iterative couplings of Lact‐Ar‐OSO2F to Ub and ANSII, afforded multiple glycosylations of these proteins so that up to three and four Lact‐Ar‐OSO2 groups were introduced in Ub and ANSII, respectively, via the formation of a sulfamoyl (OSO2‐NH) linkage.

CRISPR-based genome engineering tools are associated with off-target effects that constitutively active Cas9 protein may instigate. Previous studies have revealed the feasibility of modulating Cas9-based genome- and base-editing tools using protein or small-molecule CRISPR inhibitors. Here we screened a set of small molecule compounds with irreversible warhead, aiming to identifying small-molecule modulators of CRISPR-Cas9. It was found that selective inhibitors of nuclear export (SINEs) could efficiently inhibit the cellular activity of Cas9 in the form of genome-, base- and prime-editing tools. Interestingly, SINEs did not function as direct inhibitors to Cas9, but modulated Cas9 activities by interfering with the nuclear export process of Cas9 mRNA. Thus, to the best of our knowledge, SINEs represent the first reported indirect, irreversible inhibitors of CRISPR-Cas9. Most importantly, an FDA-approved anticancer drug KPT330, along with other examined SINEs, could improve the specificities of CRISPR-Cas9-based genome- and base editing tools in human cells. Our study expands the toolbox of CRISPR modulating elements and provides a feasible approach to improving the specificity of CRISPR-Cas9-based genome engineering tools.

No abstract

A fluorosulfuryl imidazolium salt delivers an “F−SO2+” group to phenols and amines with phenomenal efficiency. In their Communication on page 2605 ff., K. B. Sharpless, J. Dong, and co‐workers present the practical, mole‐scale synthesis of this stable, powerful reagent, which provides clickable RNHSO2F, dramatically expands the scope of SuFEx products, and constitutes a complementary alternative to SO2F2 gas delivery.

No abstract

Objective:Traditional chemical synthesis methods are cumbersome and inefficient. In this study, a novel antitumor molecule, 4-(4-(3-((6,7-bis(2-methoxyethoxy)quinazolin-4-yl)amino)phenyl)-1H-1,2,3-triazol-1-yl)phenyl sulfurofluoridate (P19G1), was identified by screening a library of Erlotinib derivatives synthesized by modular click chemistry, and the antitumor activity and underlying mechanism of P19G1 were further revealed. Methods: A series of Erlotinib derivatives (840 compounds) were synthesized using a modular click-chemistry method, and then the thiazolyl blue (MTT) method was used to screen and evaluate the inhibitory effect of these compounds on the growth and metastasis of A549 lung adenocarcinoma cells. Among them, the compound P19G1 showed the best inhibitory activity. Furthermore, the antitumor activity and mechanism of P19G1 were investigated with in vitro cell biology and in vivo assays in an animal model. Results: In vitro pharmacological studies showed that P19G1 had inhibitory effects on a variety of tumor cell lines with IC50 values in the range of 1 to 5 μM. Moreover, P19G1 significantly inhibited the proliferation and migration of the human lung adenocarcinoma cell line A549 and human colorectal cancer cell line RKO and promoted cell apoptosis. In vivo tumor-bearing mouse model experiments revealed that 50 mg/kg P19G1 effectively inhibited the growth and metastasis of A549 tumors without obvious toxicity to the host. Conclusions: The rapid structural modification of lead compounds using novel modular click-chemistry reactions holds great potential for use in obtaining diverse derivatives for tumor drug screening and development. P19G1 was discovered because of the application of click chemistry in this study, and it is an antitumor candidate molecule worthy of development.