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3,4-Hydroxypyridinone (3,4-HOPO) is a vital metal-chelating pharmacophore. However, the efficient synthesis has been a long-standing problem in drug development. In this paper, we report an efficient electrophilic activation of unprotected maltols via reversible covalent bonds between boronic acid and 3-hydroxyl/4-carbonyl. This one-pot reaction proceeded well on a gram scale in water with excellent efficiencies up to 97%. Moreover, taking advantage of the covalent interactions via the transient boronate, most of the previously tough amine donors, including sterically hindered amines, aromatic amines, and amino acids and amino alcohols, were well-tolerated. Importantly, the potential of this strategy in the pharmaceutical industry was highlighted with a successful synthesis of 3,4-HOPOs containing iron-chelating active pharmaceutical ingredients on 10 g and kilogram scales.

A simple and metal-free strategy for the regioselective synthesis of 1-N-substituted 1,2,3-triazole-4-carboxamide derivatives was developed by employing azides, HFO-1233zd(E) and amines in an aqueous reaction medium.

The development of modular, chemically diverse and regioselective reactions for expanding the cycloaddition reaction toolbox hinges heavily on a strict functional 1,3-dipole and dipolarophile pairing exploration. In this study, we...

A group-assisted-purification (GAP) chemistry strategy-based Ugi four-center three-component reaction (Ugi-4C-3CR) was explored. The reaction proceeded well to deliver the cyclic fused pyridinones selectively. Moreover, the reaction conditions were mild and avoided additional chromatography or recrystallization workup. Also, wide variations in substrates, such as anilines and aliphatic amines as well as amino alcohols and amino acid esters were all tolerated and pyridinones are achieved in good to excellent yields. Importantly, ladder-type cyclic fused pyridinones can be further constructed in excellent yield of 91%.

A domino annulation/oxidation of heterocyclic ketene aminals (HKAs) and 2-aminochalcones has been developed for the selective synthesis of poly-substituted benzo[f]imidazo[2,1-a][2,7]naphthyridines and 3-azaheterocyclic substituted 2-arylquinolines. These reactions proceed well under mild conditions without any additives. Plausible mechanisms for such a polycyclic ring system assembly were also proposed. Moreover, benzo[f]imidazo[2,1-a][2,7]naphthyridine 3g displayed a fluorescence effect, demonstrating the potential applications in organic optical materials.

A novel divergent domino annulation reaction of prop-2-ynylsulfonium salts with sulfonyl-protected β-amino ketones has been developed, affording various epoxide-fused 2-methylenepyrrolidines and S-containing pyrroles in moderate to excellent yields. Prop-2-ynylsulfonium salts act as C2 synthons in the reactions providing a promising epoxide-fused skeleton in a single operation with readily accessible starting materials.

A palladium–catalyzed ring-opening reaction of 2H-azirines with hydrazones has been developed. This protocol provides an alternative route for the construction of various polysubstituted pyrazoles with a wide substrate scope. Moreover, a plausible mechanism is proposed for this reaction, which should further enrich the chemical conversion of 2H-azirines.

An efficient, TFA-promoted cascade annulation of sulfur ylides, 2-hydroxy-β-nitrostyrenes and indoles was established. This reaction results in the construction of a diverse set of fluorescent benzofuro[3,2-b]carbazoles with the generation of seven new bonds and two new rings in a one-pot transformation. A plausible mechanism for this reaction was proposed. Moreover, the photo-physical properties of the benzofuro[3,2-b]carbazoles were observed to be simply tuned by changing the electronic nature of the peripheral substituents in the core.

A series of novel non-covalent peptidomimetic proteasome inhibitors possessing bulky group at the C-terminus and N-alkylation at the N-terminus were designed with the aim to increase metabolic stabilities in vivo. All the target compounds were screened for their inhibitory activities against human 20S proteasome, and most analogs exhibited notable potency compared with the positive control bortezomib with IC

Hypoxia is widespread in solid tumors, such as NSCLC, and has become a very attractive target. On the basis of AZD9291 scaffold, novel hypoxia-targeted EGFR inhibitors without the acrylamide warhead but containing hypoxic reductive activation groups were described. Among them, compound JT21 exhibited impressive inhibitory activity (ICsub50/sub = 23 nM) against EGFRsupL858R/T790M/supand displayed about 21-fold inhibitory activity decrease against EGFRsupwt/sup. Under hypoxia, JT21 exhibited more significant proliferation inhibitory activities against H1975 cells (ICsub50/sub = 7.39 ± 2.20 nM) and HCC827 cells (ICsub50/sub = 5.88 ± 0.85 nM) than that of AZD9291, which was about 5 times more effective than normoxia activities. Meanwhile, the weak inhibition effects on A549 and BEAS-2B cells suggested JT21 might be a selective inhibitor for EGFR mutations with low toxicity. Furthermore, JT21 could induce apoptosis of H1975 cells under hypoxia and showed good bio-reductive property.

An efficient method for the synthesis of polyfunctional imidazoles from vinyl azides and amidine has been developed. Starting from vinyl azide and amidine, this transformation proceeds without any additives and the obtained imidazoles can be decorated with ester functional group that is a promising site for further modification.

An approach for N-formylation of amines was developed using NaBH(OAc)3 as a reductant under an atmospheric pressure of CO2 at 50 °C. The corresponding formylated products of various amines, including aliphatic and aromatic amines, amines with reductive-sensitive nitro groups and alkynyl groups and benzamides were obtained in good to excellent yields, and the possible reaction mechanism was also proposed.

Novel divergent domino annulation reactions of sulfur ylides with aryldiazonium tetrafluoroborates have been developed, affording various tetra- and trisubstituted pyrazole derivatives in moderate to good yields. Three molecules of sulfur ylides were applied as C1 synthon to construct the complex products with five new chemical bonds formed in these one-pot reactions.

Substrate-controlled reactions have been developed for the synthesis of spirocyclopropylpyrazolones and bicyclic 4,5-dihydropyrazoles from 1,2-diaza-1,3-dienes and sulfur ylides. These protocols were carried out under mild reaction conditions without any additives in generally moderate to good yields. Plausible mechanisms for the transformations were proposed.

A tandem reaction of heterocyclic ketene aminals and 1,2-diaza-1,3-dienes was developed for the expedient synthesis of pyrimidopyrrolopyridazine derivatives. This process involved an intramolecular conjugate addition followed by CuCl2-catalyzed hydrazone formation.

A highly efficient approach to polysubstituted 2-amino­pyrroles containing a coumarin derivative unit at the 5-position of the pyrrole ring was developed via a novel multicomponent domino reaction of glyoxal monohydrate derivatives, anilines, coumarin derivatives, and malononitrile. This transformation proceeded via an α-amino­ketone as the key intermediate.

Transition metal-free oxidative coupling of vinyl azides with sulfonyl hydrazines is described. This radical process realized oxidative multi-functionalization of vinyl azides in the presence of potassium iodide and t-butyl hydroperoxide, selectively yielding β-keto sulfones and α-halo-β-keto sulfones in good to excellent yields with a wide tolerance of functional groups.

A novel and facile domino reaction has been developed to synthesize a variety of new derivatives from hydromorphone, amines and paraformaldehyde in good yields in a catalyst-free fashion with high atom efficiency. The products show a mixed MOR/DOR biological characteristic which makes them valuable for further study as opioid analgesics.

A divergent cascade annulation has been developed using readily available vinyl azides and carbazates with a wide range of substituents. Vinyl azides were successfully applied as bifunctional partners to prepare aza-pyrimidinones via 6-ring closure with carbazates as well as to construct polyfunctionalized imidazoles via 5-ring closure with N-substituted carbazates. The aza-heterocycles were obtained with high levels of chemoselectivity and excellent yields.

A novel series of endomorphin-1 (EM-1) and endomorphin-2 (EM-2) analogues was synthesized, incorporating chiral α-hydroxy-β-phenylalanine (AHPBA), and/or Dmt(1)-Tic(2) at different positions. Pharmacological activity and metabolic stability of the series was assessed. Consistent with earlier studies of β-amino acid substitution into endomorphins, multiple analogues incorporation AHPBA displayed high affinity for μ and δ opioid receptors (MOR and DOR, respectively) in radioligand competition binding assays, and an increased stability in rat brain membrane homogenates, notably Dmt-Tic-(2R,3S)AHPBA-Phe-NH2 (compound 26). Intracerebroventricular (i.c.v.) administration of 26 produced antinociception (ED50 value (and 95% confidence interval) = 1.98 (0.79-4.15) nmol, i.c.v.) in the mouse 55 °C warm-water tail-withdrawal assay, equivalent to morphine (2.35 (1.13-5.03) nmol, i.c.v.), but demonstrated DOR-selective antagonism in addition to non-selective opioid agonism. The antinociception of 26 was without locomotor activity or acute antinociceptive tolerance. This novel class of peptides adds to the potentially therapeutically relevant collection of previously reported EM analogues.

An efficient annulation of vinyl azides with activated imines has been developed for the synthesis of poly-functionalized imidazole derivatives. This reaction includes thermal decomposition of vinyl azides to 2H-azirines, nucleophilic attack of 2H-azirines with activated imines and subsequent cyclization to desired imidazoles.

A simple and direct synthesis of 2-aminoimidazoles from vinyl azides and cyanamide was developed. An attractive feature of this protocol is that the desired products are generated in a highly efficient and eco-friendly manner without the use of a catalyst. A plausible mechanism has been proposed.

Simple and eco-friendly synthesis of polyfunctionalized 2-aminopyrroles from vinyl azides and α-cyano derivatives has been accomplished with a good to excellent yield. The reaction was performed in ethanol/water co-solvent system without catalyst and the workup was facile. A plausible mechanism has been proposed.

Despite the remarkable benefits of gefitinib, the clinical efficacy is eventually diminished due to the acquired point mutations in the EGFR (T790M). To address this unmet medical need, we demonstrated a strategy to prepare a hybrid analogue consisting of the oxooxazolidine ring and the quinazoline scaffold and provided alternative noncovalent inhibitors targeting mutant forms of EGFR. Most of the derivatives displayed moderate to good anti-proliferative activity against gefitinib-resistant NCI-H1975. Some of them exhibited potent EGFR kinase inhibitory activities, especially on EGFR(T790M) and EGFR(L858R) kinases. SAR studies led to the identification of a hit 9a that can target both of the most common EGFR mutants: L858R and T790M. Also, 9a displayed weaker inhibitory against cancer cell lines with low level of EGFR expression and good chemical stability under different pH conditions. The work presented herein showed the potential for developing noncovalent inhibitors targeting EGFR mutants.

A novel and facile approach to polysubstituted pyrazoles from readily synthesized hydrazonyl chlorides and vinyl azides was developed. The reaction was regiospecific and proceeded under mild conditions in the presence of base.

A simple protocol for the synthesis of aminoimidazoles via base-mediated addition of cyanamide to vinyl azides followed by intramolecular cyclization is presented.

A simple, multicomponent, and straightforward reaction of vinyl azide, aldehyde, and tosylhydrazine affords the construction of 3,4,5-trisubstituted 1H-pyrazoles regioselectively in the presence of base with moderate to excellent yields. A range of functionality could be tolerated in this methodology, and a possible mechanism is proposed.

This letter describes the construction of conformationally constrained quinazoline analogues. Structure-activity relationship studies led to the identification of the lead compound 9n . Compound 9n exhibits effective in vitro activity against A431(WT,overexpression) and H1975([L858R/T790M]) cancer cell lines but is significantly less effective against EGFR negative cancer cell lines (SW620, A549, and K562). Compound 9n was also assessed for potency in enzymatic assays and in vivo antitumor studies. The results indicated that 9n is a potent kinase inhibitor against both wild-type and T790M mutant EGFR kinase. Meanwhile, an oral administration of 9n at a dose of 200 mg/kg produced a considerable antitumor effect in a A431 xenograft model, as compared to gefitinib. A preliminary pharmacokinetic study of 9n also indicates it has good pharmacokinetic properties, and therefore, it is a good starting point for further development.

Simple and eco-friendly synthesis of polyfunctionalized 2-aminopyrroles from vinyl azides and α-cyano derivatives has been accomplished with a good to excellent yield. The reaction was performed in ethanol/water co-solvent system without catalyst and the workup was facile. A plausible mechanism has been proposed.

Palladium-catalyzed C–H functionalization using guanidine as the directing group was achieved under mild reaction conditions. Various guanidine derivatives were produced in moderate to good yields by using simple unactivated arenes or ethyl acrylate as the source of arylation or olefination, respectively.

An efficient, mild, and facile method for the synthesis of the title compounds is presented from vinyl azides, e.g. (I), or carboxaldehydes such as (X).

A novel and facile approach to polysubstituted pyrazoles from readily synthesized hydrazonyl chlorides and vinyl azides was developed. The reaction was regiospecific and proceeded under mild conditions in the presence of base.

A novel and efficient metal-free carbon–nitrogen bond-forming coupling reaction between arylboronic acids and organic azides is reported. The reaction is fairly general for the preparation of secondary aromatic amines. Furthermore, the reaction is very functional-group tolerant. A possible mechanism is also proposed.

A novel and facile domino reaction has been developed to synthesize a variety of polysubstituted 4-aminopyridines from α-azidovinylketones, aldehydes and methylamine derivatives in reasonably good yields under mild conditions. Additionally, a possible mechanism is proposed.