(E)‐,(Z)‐Parallel Preparative Methods for Stereodefined β,β‐Diaryl‐ and α,β‐Diaryl‐α,β‐unsaturated Esters: Application to the Stereocomplementary Concise Synthesis of Zimelidine

Parallel and practical methods for the preparation of both (E)‐ and (Z)‐β‐aryl¹‐β‐aryl²‐α,β‐unsaturated esters 1 and (E)‐ and (Z)‐α‐aryl¹‐β‐aryl²‐α,β‐unsaturated esters 2 are described. These methods involve accessible, robust, stereocomplementary N‐methylimidazole (NMI)‐mediated enol tosylations (14 examples, 70–99 % yield), as well as stereoretentive Suzuki–Miyaura cross‐couplings (36 examples, 64–99 % yield). The highlighted feature of the present protocol is the use of parallel and stereocomplementary approaches to obtain highly (E)‐ and (Z)‐pure products 1 and 2 by utilizing sequential enol tosylations and cross‐coupling reactions. An expeditious and parallel synthesis of (E)‐ and (Z)‐zimelidine ( 3 ), which is a highly representative selective serotonin reuptake inhibitor (SSRI), was performed by utilizing the present methods.     

Why edge inversion? Theoretical characterization of the bonding in the transition states for inversion in F n NH(3−n) and FnPH(3−n) (n = 0–3)

As first noted by Dixon et al. (J Am Chem Soc 108:2461–2462, 1986), heavily fluorinated pyramidal phosphorus compounds, e.g., F _n PH_(3?n) with n > 1, invert through a T-shaped transition state (edge inversion) rather than the D_3h-like transition states (vertex inversion) found in the corresponding nitrogen compounds and less fluorinated phosphorus compounds. Subsequent studies by Dixon and coworkers established that this is a general phenomenon and has important chemical consequences. But what is the reason for the change in the structure of the transition state? Recent theoretical investigations have resulted in the discovery of a new type of chemical bond, the recoupled pair bond. In particular, it was found that recoupled pair bond dyads account for the hypervalency of the elements beyond the first row. In this paper, we show that recoupled pair bond dyads also account for the existence of the edge inversion pathway in heavily fluorinated phosphorus compounds and likely account for the presence of the lower energy inversion pathways in pyramidal compounds of other elements beyond the first row.     

Preparation of colored latex containing oil-soluble dyes with high dye content by mini-emulsion polymerization

Polymer particles containing oil-soluble dyes (colored latex particles) were prepared by mini-emulsion polymerization. Copper phthalocyanine dyes and styryl dyes were used as oil-soluble dyes. Highly hydrophobic dyes played the role of hydrophobe by themselves and enabled the full incorporation of dyes in the latex without additional hydrophobes. Two phthalocyanine dyes having similar color were blended in a mini-emulsion polymerization so that the resulting colored latex showed enough strong color depth as a colorant. Colored latexes with high dye content (more than 30 wt% for phthalocyanine dye system and 40 wt% for styryl one) and with particle size less than 100 nm were obtained.     

多乙酰氧基烷基(艹卓)酮和多羟基烷基(艹卓)酮的合成

各种溴代的烷基酚酮的乙酸酯用乙酸酐/三氟乙酸酐/乙酸(以下简称ATA)醋解可得高收率的相应的多乙酰氧基烷基酮,后者经稀酸水解几乎定量地得多羟基烷基酮。部分多乙酰氧基酮对肺癌A_(549)和上皮细胞癌显出抑制活性。     

Roles of sigmatropic migration of a benzoyl group and intermolecular hydrogen bonding between a tropone carbonyl and an NH group on the mesomorphic properties of 2-(4-alkoxybenzoyloxy)-5-alkylaminotropones and 5-alkoxy-2-(4-alkylaminobenzoyloxy)tropo

The mesomorphic properties of 2-(4-alkoxybenzoyloxy)-5-alkylaminotropones and 5-alkoxy-2-(4-alkylaminobenzoyloxy)tropones are discussed on the basis of results obtained by X-ray crystallographic and X-ray diffraction studies, as well as temperature-dependent FTIR spectral measurements. The X-ray crystallographic analysis of 2-(4-dodecylaminobenzoyloxy)-5-tetradecyloxytropone (2f) indicated that it formed a head-to-tail dimer through an intermolecular hydrogen bond between the NH and the tropone carbonyl group. The X-ray diffraction study of compound 2f suggested that the molecules formed interdigitated bilayer smectic C phases with a tilt angle of as much as c. 40° to a layer plane. The corresponding benzenoids, however, were non-mesomorphic, with higher melting points than the troponoids. In the troponoids, sigmatropic migration of the benzoyl group weakened the intermolecular hydrogen bonding and assisted the occurrence of mesomorphic properties.     

Mesomorphic properties of 2-acyloxy5-(4-alkoxyphenylazo)tropones, 2-acyloxy-5-(4-alkylphenylazo)tropones,and 2-acyloxy-5-(4-alkoxycarbonylphenylazo)tropones

Three series of mesomorphic 2-acyloxy-5-phenylazotropones with alkoxy, alkyl, and alkoxycarbonyl groups at C-4 on the phenyl ring were prepared. It was known that the corresponding 5-phenylazotropolone derivatives and their methyl ethers were not mesomorphic. 2-Acetyl-5-(4-hexyloxyphenylazo)tropone, however, shows a monotropic smectic A phase. Even an acetyl group is therefore able to induce a mesophase. The effects of terminal substitution of the tropone ring by groups such as alkoxy, alkoxycarbonyl, and alkyl on the clearing points are discussed.     

Determination of the photolytic decomposition pathways of benzylchlorodiazirine by C60 probe technique

By employing C₆₀ as a chemical probe, the photolysis of benzylchlorodiazirine has been proposed to form carbene and the rearranged products via the excited state.     

Release kinetics of (−)-menthol from chewing gum

The release kinetics of (−)-menthol from chewing gum was investigated using various encapsulated powder of (−)-menthol. The apparatus of flavor release of chewing gum was made with a glass container of mashing homogenizer. Flavor release behavior could be correlated with Avrami’s equation. Chewing gum containing (−)-menthol/γ-CD complex powder had longer retention of (−)-menthol compared with the β-CD complex powder and the (−)-menthol encapsulated in modified starches. The activation energies of (−)-menthol release from chewing gum were 106 kJ/mol for γ-CD complex and 74 kJ/mol for (−)-menthol/β-CD complex powder and emulsified (−)-menthol encapsulated in HI-CAP, respectively.     

Charge-Transfer Interactions of Aluminum Copper(I) Chloride with Polystyrene and Related Compounds

Interactions between polystyrene and aluminum copper(I) chloride (AlCuCl₄) were investigated by various spectroscopic measurements in order to elucidate the structure of polystyrene-AlCuCl₄ complex in solution and the mechanism of water resistance of the complex as a carbon monoxide absorbent. The chemical shift (101 ppm) and half line width (145 Hz) of AlCuCl₄ in benzene by ²⁷Al-NMR suggest a dimer structure bridged by two chlorine atoms, which is almost identical with that of aluminum chloride. The coordination of benzene or other aromatic compounds to AlCuCl₄ was confirmed by charge-transfer bands in UV and visible absorptions. The equilibrium constants (K) for complex formation of AlCuCl₄ with various aromatic compounds were determined by ¹³C-NMR spectroscopy. In the case of AlCuCl₄ and benzene in 1,2-dichloroethane, for example, K is 2.2 M ^?1 at 303 K. For the polymer complex solution and 1,3-diphenyl-propane solution, strong charge-transfer bands have been observed in the wavelength region at about 380 to 500 nm, where no band is observed in benzene derivatives. This strong charge-transfer band is considered to be due to the strong interaction of AlCuCl₄ with adjacent aromatic rings of polystyrene or 1,3-diphenylpropane of a chelate type, which, as a result, causes the water resistance of the present carbon monoxide absorbent system.