Abstraction of chlorine atoms from chloromethanes by the cyclohexyl radical

The kinetics of chlorine atom abstraction from the chloromethanes (CM)CCl₄, CHCl₃, and CH₂Cl₂ by radiolytically generated cyclohexyl radicals has been studied in the liquid phase by a competitive method. The halogen abstraction data have been put on an absolute basis by comparing the rates of the metathetical reactions with the known rate of addition of cyclohexyl radicals to C₂Cl₄. The following Arrhenius parameters were obtained:

Naphthaceno[5,6-cd]-1,2-dithiole,C18H10S2

C₁₈H₁₀S₂,M=290.34, monoclinic,P2₁,a=20.556(5),b=15.843(3),c=3.963(1) Å,β=92.79(2)° at 18°C,Z=4,D _x =1.496 g cm^?3,μ(Cu Kα)=3.53 mm^?1. Full-matrix least-squares refinement resulted in a final conventionalR value of 0.036 for 2030 observed reflections. The average C-S bond distance is 1.747(16) Å, the S-S bond length is 2.074(1) Å. The torsion angles at the disulfide group are close to zero, at 3.5 and 0.8°. The carbon frameworks are nearly planar, and closely approximate symmetrymmm. Bond distances are comparable with those in related molecules.     

Chronic dysphonia secondary to gastroesophageal reflux disease (GERD): Diagnosis using simultaneous dual-probe prolonged pH monitoring

The association of chronic dysphonia with gastroesophageal reflux has been reported in the otalaryngologic literature; unfortunately, these reports are primarily anecdotal. Because of the difficulty in documenting reflux, patients are often left without a definitive diagnosis or therapy. The purpose of this paper is to report on an objective method of documenting gastroesophageal reflux disease by using ambulatory esophageal and hypopharyngeal pH monitoring. 70% of the subjects who underwent simultaneous dual-probe pH monitoring evidenced reflux in the hypopharynx in both an upright and supine position. All of the subjects had erythema of the arytenoid cartilages on indirect examination; so this appears to be of clinical diagnostic significance.     

Wolkenkammeruntersuchungen der Eiskeimbildungsaktivität einiger ausgewählter Stoffe

Ohne Zusammenfassung     

Synthesis of phenols from metal-carbynes and diynes

Metal-carbynes RCM(CO)₄Br with diacetylenes give specific phenols in good yield. The reactions take only a few minutes at or below room temperature.     

Synthesis and properties of 3-vinyl-3-desmethyl chlorophyll a

The title compound 1 has been prepared from chlorophyll b by a highly chemoselective Wittig reaction, and its spectroscopic properties characterized.