2-Phenyl-2-(2-pyridyl)imidazolidine (PPI) as New Catalyst in the Efficient,Mild, and Regioselective Conversion of Epoxides to Thiocyanohydrines with Ammonium Thiocyanate

2-Phenyl-2-(2-pyridyl)imidazolidine (PPI) catalysis the addition of thiocyanate ion to epoxides to afford g -hydroxy thiocyanate in high yields, mild conditions, and regioselectivity. Thus, several 2-hydroxyethyl thiocyanates, which are useful intermediates toward biological active molecules, are obtained easily in very good yields.     

Combination thyroplasty and the "twisted larynx:" combined type IV and type I thyroplasty for superior laryngeal nerve weakness.

Vocal cord medialization through Isshiki type I thyroplasty is part of the standard approach for patients with unilateral vocal cord immobility secondary to recurrent laryngeal nerve paralysis. However, several other modalities have been used to treat the symptomatic "twisted" larynx caused by unilateral superior laryngeal nerve weakness. The Isshiki type IV thyroplasty (cricothyroid approximation) specifically addresses cricothyroid muscle weakness, but, canine studies at the Mayo Clinic demonstrated a trend toward decreased acoustic power and sound intensity with simulated cricothyroid activity. Thus it is reasoned that addition of an ipsilateral type I thyroplasty should help compensate for this power loss. Using videostroboscopic and acoustic analysis, 9 patients with unilateral superor laryngeal nerve weakness were treated with combination type IV and type I thyroplasty. Subjective dysphonia and objective visual and acoustic measurements revealed postoperative improvement in most patients. The combination type IV and type I thyroplasty is recommended for surgical treatment of patients with superior laryngeal nerve weakness, because it addresses cricothyroid muscle weakness without compromising vocal power.     

Investigation of the effects of ionic hydrogen bonds (COH–C and N–HOC) in crystalline dl-proline by ab initio and DFT calculated NQR parameters

In this paper, we have calculated the nuclear quadrupole resonance (NQR) parameters of the quadrupole nuclei involved in the hydrogen bonds (CO⁻H–C and ⁺N–H⁻OC) in the monomer and pentameric cluster of dl-proline by HF and B3LYP methods and basis sets of 6-311+G^* and 6-311++G^**. These computations are performed on the basis of X-ray diffraction structural data of dl-proline. The results indicate that the calculations including hydrogen-bonding (HB) interactions (in pentamer) are in better agreement with the experimental data than those in which these interactions are neglected (in monomer). The quantum chemical calculations show that the intermolecular hydrogen-bonding interactions play an important role in determination of the NQR parameters of ¹⁴N, ²H of group and ¹⁷O.     

A green synthesis of spirooxindole derivatives catalyzed by SiO2@g-C3N4 nanocomposite

Research on Chemical Intermediates - In this study, SiO2 nanoparticles were immobilized onto the surface of g-C3N4 nanosheets. The characterization of SiO2@g-C3N4 nanocomposite has been done by...