Synthesis of Glycoborine,Glybomine A and B,the Phytoalexin Carbalexin A and the β‐Adrenoreceptor Antagonists Carazolol and Carvedilol

We describe a regioselective synthesis of 4‐ or 5‐substituted carbazoles by oxidative cyclisation of meta‐oxygen‐substituted N‐phenylanilines. Using the regiodirecting effect of a pivaloyloxy group, we prepared 4‐hydroxycarbazole, a precursor for the enantiospecific synthesis of the β‐adrenoreceptor antagonists (?)‐(S)‐carazolol ( 5 ) and (?)‐(S)‐carvedilol ( 6 ). Regioselective palladium(II)‐catalysed cyclisation of different diarylamines led to total synthesis of glycoborine ( 7 ) and the first total syntheses of the phytoalexin carbalexin A ( 8 ), glybomine A ( 9 ) and glybomine B ( 10 ). For glybomine B ( 10 ), a 5‐hydroxycarbazole was converted into the corresponding triflate and utilized for introduction of a prenyl substituent.     

Generalized Qubit Portrait of the Qutrit-State Density Matrix

We obtain new inequalities for tomographic probability distributions and density matrices of qutrit states by generalization of the qubit-portrait method. We propose an approach based on the quditportrait method of obtaining new entropic inequalities. Our approach can be applied to the case of arbitrary nonnegative hermitian matrices, including the density matrices of multipartite qudit states.     

Experimental study of electron density distribution in crystals of antimony(V) dicarboxylate complexes

Structural Chemistry - The molecular structure and charge density distribution in the crystals of triphenylantimony bis[(2E)-3-phenylprop-2-enoate] [Ph3Sb(O2CCH=CHPh)2] and triphenylantimony...     

Rethinking Cysteine Protective Groups: S‐Alkylsulfonyl‐l‐Cysteines for Chemoselective Disulfide Formation

The ability to reversibly cross‐link proteins and peptides grants the amino acid cysteine its unique role in nature as well as in peptide chemistry. We report a novel class of S‐alkylsulfonyl‐l ‐cysteines and N‐carboxy anhydrides (NCA) thereof for peptide synthesis. The S‐alkylsulfonyl group is stable against amines and thus enables its use under Fmoc chemistry conditions and the controlled polymerization of the corresponding NCAs yielding well‐defined homo‐ as well as block co‐polymers. Yet, thiols react immediately with the S‐alkylsulfonyl group forming asymmetric disulfides. Therefore, we introduce the first reactive cysteine derivative for efficient and chemoselective disulfide formation in synthetic polypeptides, thus bypassing additional protective group cleavage steps.     

Solution Behavior of Hyperbranched Polymethylsilsesquioxane with Intramolecular Cycles

Samples of hyperbranched polymethylsilsesquioxanes were synthesized at various polycondensation times and intramolecular cycle amounts. The samples were studied in solutions in toluene and hexane. It is shown that increasing the polycondensation duration results in the growth of number of cycles and intramolecular density that correlates with changes of molecular, hydrodynamic, and optic properties.     

Stereoselective arylthiolation of dehydroalanine in the NiII coordination environment: the stereoinductor of choice

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Radical polymerization of radical-labeled monomers: The triarylmethyl-based radical monomer as an example

Recent development of spin-labeled nitroxide-mediated polymerization (NMP) involving successful polymer preparation with high livingness and narrow dispersity in the presence of persistent trityl-based stable radicals attached to the initiators (90% recovery of a trityl radical signal after the polymerization) led us to the preparation of stable organic radical polymers based on trityl radical-substituted monomers using NMP as the method of polymerization despite the claims in the literature about its expected failure. Here, we present successful radical polymerization and NMP of a trityl radical-based tri- and mono-monomer yielding more than 90% recovery of the trityl radical signal. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2656–2664