Synthesis and Inclusion Properties of the Host Compound 1,3-Dihydro-1,1,3,3-tetraphenylisobenzofuran. X-Ray Crystal Structures of the Free Host and of an Inclusion Compound with 1,4-Dioxane

A novel host molecule, 1, suitable for crystalline lattice-type inclusion, has been synthesized, and its cocrystal formation ability has been investigated. Host 1 proved to be of potential use for organic solvent separation and retrieval, and a promising auxiliary for solidification of certain odorous substances. The crystal structures of the solvent-free host 1, and its complex with 1,4-dioxane (1 : 1), have been determined by single crystal X-ray diffraction. The structure of 1 (guest-free) is triclinic, P , with a = 9.452(2), b = 10.359(3), c = 13.116(3) Å, = 101.80(2), = 106.53(1) and = 104.32(1)°. The spacious, propeller-like molecules are held together by weak van der Waals' forces. The dioxane inclusion compound is monoclinic, P21/a, with a = 15.050(1), b = 8.641(1) and c = 20.658(1) Å, and = 94.56(1)°, and contains two crystallographically independent guest molecules, both located around symmetry centres. The molecular packing seems to be governed by C—H···O type bonds (C···O = 3.31 and 3.48 Å) from the host to the dioxane oxygens.     

Synthesen von Heterocyclen, 72. Mitt.: 4-Phenyl-3,4-dihydro-carbostyrile aus α-Cyanzimtsäureamiden

Zusammenfassung Bei der Reaktion vonSchiffschen Basen mit Cyanacetylchlorid entstehen über labile Addukte -Cyanzimtsäure-anilide, die in Gegenwart von AlCl₃ zu Derivaten des 3-Cyan-4-phenyl-3,4-dihydrocarbostyrils reagieren. Aus diesen kann durch Verseifung die Cyangruppe eliminiert werden.

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The reaction of azomethines with cyanoacetyl chloride leads via instable adducts to -cyanocinnamic anilides, which with AlCl₃ undergo cyclisation to derivatives of 3-cyano-4-phenyl-3,4-dihydrocarbostyrils. The cyano group in these compounds can be removed by hydrolysis and decarboxylation.

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Herrn KollegenO. Hromatka, Wien, mit den besten Wünschen zum 60. Geburtstag.     

Gas chromatographic analysis of traces of hydrogen sulfide in hydrogen

Summary A simple gas chromatographic method has been developed for analysis of hydrogen sulfide in hydrogen at the 0.5 to 100 ppm level. After enriching the traces of hydrogen sulfide by absorption in a gas loop packed with the chosen column support at 77 K it was determined by using a Chromosorb G column with silicone 550 and phthalic anhydride as liquid phases, hydrogen as carrier gas and a thermal conductivity detector. The detection limit was found to be about 0.5 ppm of hydrogen sulfide.     

Application of γ-cyclodextrin for the stabilization and/or dispersion of vegetable oils containing triglycerides of

To improve the storage stability of instable vegetable oils with a high content of polyunsaturated fatty acid triglycerides, these essential compounds can be complexed with native cyclodextrins. Only with -CD a nearly complete complexation of the oils was achieved as shown by complexation kinetics measurements. Storage trials of the insoluble CD-complexes followed by the determination of the peroxide value of the oils indicated that the best stabilization against autoxidation is obtained with -CD. An additional benefit of the complexation of triglycerides of polyunsaturated fatty acids with -cyclodextrin is the formation of stable dispersions of these oils in aqueous media.     

Influence of β‐Cyclodextrin on the Mixed Micellization Process of Sodium Dodecyl Sulfate and Sodium Lauroyl Sarcosine and Formation of Inclusion Complexes

In this work, we have studied the influence of different concentrations of β‐Cyclodextrin (β‐CD) on the mixed micellization of anionic surfactants sodium dodecyl sulfate (SDS) and sodium lauroyl sarcosine (SLAS) at different SDS mole fractions (α_SDS). From conductivity data, the critical micellar concentration (cmc), the equivalent ionic conductivities of the monomeric species (Λ_m), the associated species (Λ_assc) and the micelle (Λ_mic), the degree of counterion dissociation (α) in the presence of β‐CD were evaluated from the slope of the conductivity versus concentration plots for the pure and binary mixtures. The apparent cmc of the surfactants vary linearly with the β‐CD concentrations. From the dependence of cmc of the surfactants on β‐CD concentration, we have deduced the association constant (K) of surfactant‐β‐CD inclusion complexes assuming 1∶1 stoichiometry. Theories of Clint, Regular solution, and Motomura's have been used for the evaluation of ideality or nonideality of the mixed system. Mixed micelles were found to be rich in SDS content at the cmc in the presence and the absence of β‐CD. The cmc values have been used to evaluate the transfer of standard free energy of micelles (ΔG⁰ _M,tr) from the aqueous medium to additive medium.     

Interactions of γ-Cyclodextrin with the Mixed Micelles of Anionic Surfactants and Their Inclusion Complexes Formation

Interactions of γ-cyclodextrin (γ-CD) with the single and mixed micelles of sodium dodecyl sulfate (SDS) and sodium lauroyl sarcosine (SLAS) have been studied at different concentrations of γ-CD by using conductivity measurements. From conductivity data, the pure and mixed critical micellar concentration (cmc), the equivalent ionic conductivities of the monomeric species (Λ _m), the associated species (Λ _assc) and the micelle (Λ _mic), the degree of counterion dissociation (χ) in the presence of γ-CD have been evaluated from the slope of the conductivity versus concentration plots for the pure and binary mixture of surfactants. From the dependence of cmc of the surfactantson γ-CD concentration, we have deduced the association constant (K) of surfactant-γ-CD inclusion complexes assuming 2:1 stoichiometry. Theories of Clint, regular solution, and Motomura's have been used for the evaluation of ideality or nonideality of the mixed system. Mixed micelles were found to be rich in SDS content in the presence and the absence of γ-CD. The cmc values have been used to evaluate the transfer of standard free energy of micelles (ΔG⁰ _M,tr) from the aqueous medium to additive medium.     

Numerical sensitivity of trajectories across conformational energy hypersurfaces from geometry optimized molecular orbital calculations: AM1, MNDO,and MINDO/3

The monocyclic β-lactam [[4(S)-methyl-2-oxo-1-azetidinyl]thia]acetic acid was studied by the semiempirical molecular orbital methods AM1, MNDO, and MINDO/3. Using the reaction coordinate option in the program MOPAC on VAX and Cray X-MP computers, the potential energy curve was calculated for rotation of the C2-N1-S-C torsional angle in the conformationally flexible side chain while optimizing all other geometrical variables in the molecule. The trajectory taken during geometry optimization was found to be sensitive to the computer, the program version, the convergence criteria, and the degree of code optimization used in the calculation. In order to reduce the likelihood of spurious results, conformational or reaction energy hypersurfaces need to be calculated with the more precise SCF convergence and minimization criteria available in programs for MINDO/3, MNDO, and AM1 calculations. The nitrogen in the model β-lactam antibiotic is predicted to invert periodically as the dihedral angle to the exocyclic N-substituent sweeps through 360°.