Phage PBR31: Classifying the Unclassifiable.

The ability of bacteriophages to destroy bacteria has made them the subject of extensive research. Interest in bacteriophages has recently increased due to the spread of drug-resistant bacteria, although genomic research has not kept pace with the growth of genomic data. Genomic analysis and, especially, the taxonomic description of bacteriophages are often difficult due to the peculiarities of the evolution of bacteriophages, which often includes the horizontal transfer of genes and genomic modules.

Mechanism of the Ullmann Biaryl Ether Synthesis Catalyzed by Complexes of Anionic Ligands: Evidence for the Reaction of Iodoarenes with Ligated Anionic Cu Intermediates.

A series of experimental studies, along with DFT calculations, are reported that provide a detailed view into the mechanism of Ullmann coupling of phenols with aryl halides in the presence of catalysts generated from Cu(I) and bidentate, anionic ligands. These studies encompass catalysts containing anionic ligands formed by deprotonation of 8-hydroxyquinoline, 2-pyridylmethyl tert-butyl ketone, and 2,2,6,6-tetramethylheptane-3,5-dione. Three-coordinate, heteroleptic species [Cu(LX)OAr] were shown by experiment and DFT calculations to be the most stable complexes in catalytic systems containing 8-hydroxyquinoline or 2-pyridylmethyl tert-butyl ketone and to be generated reversibly in the system containing 2,2,6,6-tetramethylheptane-3,5-dione.

Snap deconvolution: An informatics approach to high-throughput discovery of catalytic reactions.

We present an approach to multidimensional high-throughput discovery of catalytic coupling reactions that integrates molecular design with automated analysis and interpretation of mass spectral data. We simultaneously assessed the reactivity of three pools of compounds that shared the same functional groups (halides, boronic acids, alkenes, and alkynes, among other groups) but carried inactive substituents having specifically designed differences in masses. The substituents were chosen such that the products from any class of reaction in multiple reaction sets would have unique differences in masses, thus allowing simultaneous identification of the products of all transformations in a set of reactants.

Nucleophilicity Parameters of Stabilized Iodonium Ylides for Characterizing Their Synthetic Potential.

Kinetics and mechanisms of the reactions of the β-dicarbonyl-substituted iodonium ylides 1(a-d) with several π-conjugated carbenium and iminium ions have been investigated. All reactions proceed with rate-determining attack of the electrophile at the nucleophilic carbon center of the ylides to give iodonium ions, which rapidly expel iodobenzene and undergo different subsequent reactions. The second-order rate constants k2 for the reactions of the iodonium ylides with benzhydrylium ions correlate linearly with the electrophilicity parameters E of the benzhydrylium ions and thus follow the linear free energy relationship log k(20 °C) = sN(N + E) (eq 1), where electrophiles are characterized by one parameter (E), while nucleophiles are characterized by two parameters: the nucleophilicity N and the susceptibility sN.

Crystal structure of 2-[chloro-(4-meth-oxy-phen-yl)meth-yl]-2-(4-meth-oxy-phen-yl)-5,5-di-methyl-cyclo-hexane-1,3-dione.

In the title compound, C23H25ClO4, the cyclo-hexane ring adopts a chair conformation with the 4-meth-oxy-phenyl substituent in an axial position and the chloro-(4-meth-oxy-phen-yl)methyl substituent in an equatorial position. The packing features inversion dimers formed by pairs of C-H⋯O contacts and strands along [100] and [010] established by further C-H⋯O and C-H⋯Cl contacts, respectively.

Crystal structure of (1S,2R)-6,6-dimethyl-4,8-dioxo-2-phenyl-spiro-[2.5]octane-1-carbaldehyde.

In the title compound, C17H18O3, the two non-spiro C atoms of the cyclo-propane ring bear a formyl and a phenyl substituent which are trans-oriented. In the crystal, mol-ecules are linked by weak C-H⋯O and C-H⋯π contacts resulting in a three-dimensional supra-molecular structure.

Electrophilicities of benzaldehyde-derived iminium ions: quantification of the electrophilic activation of aldehydes by iminium formation.

Rate constants for the reactions of benzaldehyde-derived iminium ions with C-nucleophiles (enamines, silylated ketene acetals, and enol ethers) have been determined photometrically in CH3CN solution and used to determine the electrophilicity parameters E of the cations defined by the correlation log k(20°C) = s(N)(E + N) (Mayr, H.; et al. J.

Electrofugalities of 1,3-diarylallyl cations.

Heterolysis rate constants k1 of differently substituted 1,3-diarylallyl halides and carboxylates have been determined in various solvents. The linear free energy relationship log k1 = s(f)(N(f) + E(f)) was found to predict the heterolysis rates (log k1) of 1,3-diarylallyl derivatives with a standard deviation of 0.26, corresponding to a factor of 1.

Ion pair dynamics: solvolyses of chiral 1,3-diarylallyl carboxylates as a case study.

Chiral ion pairs play a key role in modern enantioselective synthesis, though little is known about their properties. We have now used the special features of unsymmetrically substituted allyl derivatives to obtain unprecedented insight into ion pair dynamics. By employing chiral high-performance liquid chromatography, it was possible to follow the time-dependent concentrations of all four isomeric esters (two regioisomeric pairs of enantiomers) and all four isomeric alcohols generated during the hydrolysis of enantiopure 1-(4-chlorophenyl)-3-phenylallyl and 3-(4-chlorophenyl)-1-phenylallyl 4-nitrobenzoates.

(R,E)-3-(4-Chloro-phen-yl)-1-phenyl-allyl 4-nitro-benzoate.

The title compound, C(22)H(16)ClNO(4), adopts a conformation in which the phenyl ring plane forms similar dihedral angles with the nitro-benzoate C(6) ring [76.97 (8)°] and the chloro-phenyl group [76.95 (8)°]; the dihedral angle between the chloro-phenyl and nitro-benzoate rings is 66.

Electrophilicities of symmetrically substituted 1,3-diarylallyl cations.

Kinetics of the reactions of nine symmetrically substituted 1,3-diarylallyl cations with different nucleophiles were studied photometrically in dichloromethane, acetonitrile, and DMSO solutions. The second-order rate constants k(2) were found to follow the correlation log k(2) = s(N)(N + E). The electrophilicity parameters E of the title cations were derived, using the known values of s(N) and N of the nucleophilic reaction partners, and compared with the electrophilicities of analogously substituted benzhydrylium ions.