Keywords: 2-Aminobenzothiazole / Dibenzothiazolyltetraazathiapentalene / Electrophilic and nucleophilic sulfur atoms Reactions between CS 2 and the exocyclic amino groups of 2-aminobenzothiazoles gave series of molecules bearing thiourea, isothiourea, dithiocarbamate, dithiocarboimine, dimethyldithiocarbamate, methyldithiocarbamate, S-CH 3 and O-alkyl thiocarbamic ester, and guanidine groups. Preferred tautomers and conformers were determined. Most compounds present coordinative bonds between the endocyclic sulfur atom, which behaves as a Lewis acid, and oxygen, ni-

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The mechanochemically induced complexation between diethyl N,N′-1,3-phenyldioxalamate tweezers and resorcinol, orcinol, 4,6-di-tert-butyl-1,3-benzenediol, and 4-hexyl-1,3-benzenediol is described. IR-spectroscopy, X-ray powder diffraction, 13C CPMAS, and single X-ray diffraction allowed establishing the structures of the complexes as hydrogen-bonded heterodimers and heterotetramers. Complexation occurs through O–H···OC hydrogen-bonding interactions with the participation of phenolic OH and amide carbonyl groups. The initial conformation and steric factors coming from the 1,3-benzenediols exert a strong influence on the final structure of the complex formed. Complexation twists both oxalyl arms by 180°, strengthens the intramolecular (amide)CO···H(Csp 2)···OC(amide) three-centered hydrogen bond, and moves apart the oxalyl arms to allow the accommodation of the 1,3-benzenediol inside the cavity. The supramolecular architectures of the complexes in 1-D are directed by R 1 2(6), R 2 2(10), and R 1 2(6) adjacent hydrogen-bonding ring motifs; meanwhile, the 2-D and 3-D arrays are driven by multipolar interactions. Theoretical DFT calculations at the B3LYP/6-31G(d,p) level of theory were performed to support the experimental findings. The complexes herein reported constitute the first examples of molecular complexes with phenyldioxalamate.

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Here, we describe the first systematic study on the mechanism of substrate-selective inhibition of mammalian ALOX15 orthologs. For this purpose, we prepared a series of N-substituted 5-(1H-indol-2-yl)­anilines and found that (N-(5-(1H-indol-2-yl)-2-methoxyphenyl)­sulfamoyl)­carbamates and their monofluorinated analogues are potent and selective inhibitors of the linoleate oxygenase activity of rabbit and human ALOX15. Introduction of a 2-methoxyaniline moiety into the core pharmacophore plays a crucial role in substrate-selective inhibition of ALOX15-catalyzed oxygenation of linoleic acid at submicromolar concentrations without affecting arachidonic acid oxygenation. Steady-state kinetics, mutagenesis studies, and molecular dynamics (MD) simulations suggested an allosteric mechanism of action. Using a dimer model of ALOX15, our MD simulations suggest that the binding of the inhibitor at the active site of one monomer induces conformational alterations in the other monomer so that the formation of a productive enzyme–linoleic acid complex is energetically compromised.

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Arachidonic acid lipoxygenases (ALOXs) have been suggested to function as monomeric enzymes, but more recent data on rabbit ALOX15 indicated that there is a dynamic monomer-dimer equilibrium in aqueous solution. In the presence of an active site ligand (the ALOX15 inhibitor RS7) rabbit ALOX15 was crystalized as heterodimer and the X-ray coordinates of the two monomers within the dimer exhibit subtle structural differences. Using native polyacrylamide electrophoresis, we here observed that highly purified and predominantly monomeric rabbit ALOX15 and human ALOX15B are present in two conformers with distinct electrophoretic mobilities. In silico docking studies, molecular dynamics simulations, site directed mutagenesis experiments and kinetic measurements suggested that in aqueous solutions the two enzymes exhibit motional flexibility, which may impact the enzymatic properties.