Cyclization of Gold Acetylides: Synthesis of Vinyl Sulfonates via Gold Vinylidene Complexes

Differently substituted terminal alkynes that bear sulfonate leaving groups at an appropriate distance were converted in the presence of a propynyl gold(I) precatalyst. After initial formation of a gold acetylide, a cyclization takes place at the β‐carbon atom of this species. Mechanistic studies support a mechanism that is related to that of dual gold‐catalyzed reactions, but for the new substrates, only one gold atom is needed for substrate activation. After formation of a gold vinylidene complex, which forms a tight contact ion pair with the sulfonate leaving group, recombination of the two parts delivers vinyl sulfonates, which are valuable targets that can serve as precursors for cross‐coupling reactions, for example.     

Stroboscopic signs associated with benign lesions of the vocal folds

Stroboscopic signs were systematically rated for a group of 80 patients with benign vocal fold lesions, most of whom had either a nodule or a polyp. Each group revealed a characteristic pattern of ranking of signs and exhibited differences of most predominant signs. The results of the ratings were submitted to a multiple discriminant analysis to determine if post hoc stroboscopic ratings could be used to correctly classify patients into one of four diagnostic groups and into one of two treatment groups. All patients except one were correctly classified into the diagnostic groups, and all were correctly classified into the treatment groups. The important signs for classifying patients into the diagnostic groups were roughness of the edge of the affected vocal fold, phase closure pattern, and phase symmetry. The important signs for classifying patients into the treatment groups were roughness of the edge of the affected vocal fold, glottal closure configuration, and vibration characteristics of the affected (or more affected) vocal fold. The results suggest that objective evaluation of stroboscopic examinations can be valuable in correctly diagnosing patients and in selecting the proper treatment regimen for the patient.     

Synthesis,crystal and molecular structure of 1,3-dimethyl-10-benzyl-2,4,9-trioxo-1,3,6,7,8,10-hexahydro-1,3-diazepino-[2,1-f]-purine

The crystal and molecular structure of the title compound, obtained as a result of intramolecular cyclization of 4-(8-benzylaminotheophylline-7-yl)-butanoic acid, has been determined by X-ray diffraction. Two rings, (comprising the theophylline skeleton) are planar, but the 7-membered 1,3-diazepinon ring is undulated, with a twisted chair conformation.     

Experimental and theoretical study of the photophysics and structures of europium cryptates incorporating 3,3'-bi-isoquinoline-2,2'-dioxide.

A detailed photophysical study of [Eu within (biqO2.2.2)(CF3SO3)](CF3SO3)2. CH3CN.H2O (Eu within 1) and two other types of cryptates incorporating three 3,3'-biisoquinoline-2,2'-dioxide units has been performed. Structural crystallographic data of Eu within 1, electronic structure calculations and theoretical models were used to obtain the intramolecular energy transfer rates and the appropriate set of rate equations, which was solved numerically. Quantum yields and decay lifetimes were obtained from these results and compared to the experimental data. The role of the ligand-to-metal charge transfer (LMCT) states was ascertained. A theoretical ligand field and intensity analysis was carried out and the results agree very well with the emission spectra. The molecular structures of the lanthanide cryptates were successfully modelled by the YIII ion using the restricted Hartree-Fock (RHF) method, with the advantage of dealing with closed-shell systems. These molecular structures were used to explain the drastic differences in the photophysics of the three EuIII cryptates.     

External heavy atom effect on the triplet state of aromatic hydrocarbons: IV. Fluorene,triphenylene-d12 and coronene

The phosphorescence decay functions and spectra of ethanol solutions of triphenylene-d₁₂, coronene and fluorene were observed in the presence of different KI concentrations at 77 K. The analysis of the dependence of phosphorescence (T₁ → S₀) rate constant, k_PT, and intersystem crossing (T₁ ? S₀) rate constant, k_GT, on triplet energies E_T of aromatic molecules and on the distance between the heavy atom and the aromatic molecule show that the external heavy atom effects on k_PT and k_GT are essentially of the second and third order, respectively. The phosphorescence spectra of triphenylene and coronene show the presence of the third order contributions in the radiative transition, which involves the second triplet state of aromatic molecule.     

Reaction of 5,5-diphenyl-2-thiohydantoin with 1,2-dibromoethane.crystal and molecular structures of 2,3-dihydro-6,6-diphenylimi-dazo-[2,1-b]-thiazol-5(6h)-one and 2,3-dihydro-5,5-diphenylimi-dazo-[2,-1-b]-thiazol-6(5h)-one and their reactivity

The crystal and molecular structures of the title isomeric compounds $\text{1}$ and $\text{2}$, obtained by intramolecular N,S--dialkylation of 5,5-diphenyl-2-thiohydantoin with 1,2-dibro-moethane, have been determined from X-ray diffractometer data. 2,3-Dihydro-6,6-diphenylimidazo-[2,1-b]-thiazol-5(6H)-one $\text{1}$ crystallizes in space group P2₁2₁2₁ with a=11.376(3), b=12,255(5), c=8.434(3) Å and Z=4. Crystals of $\text{2}$, containing one molecule of benzene, are monoclinic,space group P2₁/c with a=11.539(6), b=10.242(3), c=16.353(5) Å, β=95.45(5)° and Z=4. In both cases a planar geometry of the two fused five-membered heterocyclic rings was found. The selected bond lengths in $\text{1}$ and $\text{2}$, as well as those analogous imidazothiazinones $\text{3}$ and $\text{4}$, were used to calculate E_HOSE (Harmonic Oscillation Stabilization Energy). The problem of stability and chemical reactivity of compounds $\text{1}$ to $\text{4}$ is also discussed.     

2-Aroylbenzoic acids—VIII: The synthesis and some reactions of 2-aroylbenzoic acids from m-chlorophenol

The syntheses of the novel 2-(4′-chloro-2′-hydroxybenzoyl) benzoic acid 1 and 2-(2′-chloro-4′-hydroxybenzoyl)benzoic acid 2 are described and some of their reactions are given.     

Analysis of spasmodic dysphonia by aerodynamic and laryngostroboscopic measurements

Sequential assessment of laryngeal function using laryngostroboscopy and phonatory air flow assessment was carried out in 18 patients with spasmodic dysphonia (SD). Comparison was made between findings in patients before treatment (n = 18), after unilateral recurrent nerve block by lidocaine (n = 6), after bilateral injections of botulinum toxin (Botox) (n = 13), and prior to Botox reinjection (n = 3). Unilateral nerve block resulted in higher mean phonatory airflows than after bilateral Botox injections. Both unilateral nerve block and Botox injections increased fluctuant or alternating flow source (AC); however, unilateral nerve block resulted in more unmodulated airflow leakage. Phonation time on a single breath was longer than with Botox injection. Bilateral Botox injections resulted in better glottal closure, fewer instances of vocal fold level differences, and, better vocal fold vibrations with phase symmetry, as determined by laryngostroboscopy. Partial bilateral denervation using Botox resulted in laryngeal function, which appeared to be intermediate between that of tightly squeezed pretreatment status and a breathy voice with incomplete adduction after unilateral nerve block. Of all treatments assessed, bilateral partial denervation by Botox appeared to be the most physiologic in restoring normal vocal fold vibratory function and airflow.     

Elliptic Functions With Critical Points Eventually Mapped Onto Infinity

We consider the class of elliptic functions whose critical points in the Julia set are eventually mapped onto ∞. This paper is a continuation of our previous papers, namely [11] and [12]. We study the geometry and ergodic properties of this class of elliptic functions. In particular, we obtain a lower bound on the Hausdorff dimension of the Julia set that is bigger than the estimate proved in [11]. Let h be the Hausdorff dimension of the Julia set of f. We construct an atomless h-conformal measure m and prove the existence of a (unique up to a multiplicative constant) σ-finite f-invariant measure μ equivalent to m. The measure μ is ergodic and conservative.