Abstract Peptidomimetics with a substituted imidazo[1,2-a]pyridine fragment were synthesized by a tandem of Groebke–Blackburn–Bienaymé and Ugi reactions. The target products contain substituted imidazo[1,2-a]pyridine and peptidomimetic moieties as pharmacophores with four diversity points introduced from readily available starting materials, including scaffold diversity. A small focused compound library of 20 Ugi products was prepared and screened for antibacterial activity. Beilstein J. Org. Chem. 2023, 19, 727–735. doi:10.3762/bjoc.19.53 ..read more

Abstract A palladium-catalyzed enantioselective three-component reaction of glyoxylic acid, sulfonamides and aryltrifluoroborates is described. This process provides modular access to the important α-arylglycine motif in moderate to good yields and enantioselectivies. The formed α-arylglycine products constitute useful building blocks for the synthesis of peptides or arylglycine-containing natural products. Beilstein J. Org. Chem. 2023, 19, 719–726. doi:10.3762/bjoc.19.52 ..read more

Abstract The dibenzo[b,f]azepine skeleton is important in the pharmaceutical industry, not only in terms of existing commercial antidepressants, anxiolytics and anticonvulsants, but also in reengineering for other applications. More recently, the potential of the dibenzo[b,f]azepine moiety in organic light emitting diodes and dye-sensitized solar cell dyes has been recognised, while catalysts and molecular organic frameworks with dibenzo[b,f]azepine derived ligands have also been reported. This review provides a brief overview of the different synthetic strategies to dibenzo[b,f]azepines and o ..read more

Abstract Phostams, phostones, and phostines are a series of 1,2-azaphosphaheterocycle and 1,2-oxaphosphaheterocycle 2-oxide derivatives. They are phosphorus analogues of lactams and lactones and important biologically active compounds. The strategies for the synthesis of medium and large phostams, phostones, and phostines are summarized. They include cyclizations and annulations. Cyclizations achieve ring construction through the formations of C–C, C–O, P–C, and P–O bonds in the rings, while annulations build the rings via [5 + 2], [6 + 1], and [7 + 1] fashions with the stepwise formation of t ..read more

Abstract A set of novel 1,4-diaryl-1,3-butadiynes terminated by two 7-(arylethynyl)-1,8-bis(dimethylamino)naphthalene fragments was prepared via the Glaser–Hay oxidative dimerization of 2-ethynyl-7-(arylethynyl)-1,8-bis(dimethylamino)naphthalenes. The oligomers synthesized in this way are cross-conjugated systems, in which two conjugation pathways are possible: π-conjugation of 1,8-bis(dimethylamino)naphthalene (DMAN) fragments through a butadiyne linker and a donor–acceptor aryl–C≡C–DMAN conjugation path. The conjugation path can be “switched” simply by protonation of DMAN fragments. X-ray di ..read more

Abstract The importance of functionalized imidazo heterocycles has often been featured in several impactful research both from academia and industry. Herein, we report a direct C-3 acetoxymalonylation of imidazo heterocycles using relay C–H functionalization enabled by organophotocatalysis starring zinc acetate in the triple role of an activator, ion scavenger as well as an acetylating reagent. The mechanistic investigation revealed a sequential sp2 and sp3 C–H activation, followed by functionalization driven by zinc acetate coupled with the photocatalyst PTH. A variety of imidazo[1,2-a]pyridi ..read more

Abstract Two new cassane diterpenoids, 14β-hydroxycassa-11(12),13(15)-dien-12,16-olide (1) and 6′-acetoxypterolobirin B (3), together with a known analogue, identified as 12α,14β-dihydroxycassa-13(15)-en-12,16-olide (2), were isolated from the fruits of Pterolobium macropterum. Compound 1 is a cassane diterpenoid with a Δ11(12) double bond conjugated with an α,β-butenolide-type, whereas compound 3 is a dimeric caged cassane diterpenoid with unique 6/6/6/6/6/5/6/6/6 nonacyclic ring system. The structures of 1 and 3 were characterized by extensive spectroscopic analysis combined with computation ..read more

Abstract Pyrrolo[2,1-b][1,3]benzothiazoles are an important class of fused sulfur and nitrogen-containing heterocycles intensively studied in medicinal chemistry and pharmacology. In the present paper, a new synthetic approach to pyrrolobenzothiazoles is developed based on 1,4-thiazine ring contraction in 3-aroylpyrrolo[2,1-c][1,4]benzothiazine-1,2,4-triones under the action of nucleophiles. The proposed approach works well with alkanols, benzylamine, and arylamines. The scope and limitations of the developed approach are studied. The synthesized pyrrolobenzothiazole derivatives represent an i ..read more

Abstract We synthesized a new tetraphenylethylene-modified chitosan bioconjugate, CS-TPE, that shows the aggregation-induced emission effect. It can self-assemble into fluorescent polymeric nanoparticles in an aqueous solution at pH 5.3 either alone or with the water-soluble bowl-shaped six-fold carboxylated tribenzotriquinacene derivative TBTQ-C6 via host–guest binding. The spherical nanoparticles formed by CS-TPE amphiphiles or TBTQ-C6/CS-TPE supra-amphiphiles disintegrated under alkaline stimulation at pH 10.4 and the dispersion of the aggregates after the collapse in the presence of TBTQ-C ..read more

Abstract Metal enolates are useful intermediates and building blocks indispensable in many organic synthetic transformations. Chiral metal enolates obtained by asymmetric conjugate additions of organometallic reagents are structurally complex intermediates that can be employed in many transformations. In this review, we describe this burgeoning field that is reaching maturity after more than 25 years of development. The effort of our group to broaden possibilities to engage metal enolates in reactions with new electrophiles is described. The material is divided according to the organometallic ..read more