11 beta-methyl-19-norsteroids: novel progestational hormones

The synthesis and biological properties of 2 11beta-methyl-19-norsteroids (17alpha-ethynyl-17beta-hydroxy-11beta-methylestr-4en-3-one and 3beta, 17beta-diacetoxy-17alpha-ethynyl-11beta-methylestr-4-ene) are described. In experimental animals both compounds exhibited potent progestational activities, antiestrogenic activities, and estrogenic responses in the estrogen-deficient state. It is suggested that the latter compound may be similar to other progestational agents in failing to alter hepatic excretory function and may possess anovulatory properties without some of the side effects associated with steroid contraceptives presently employed.     

11β-methyl-19-norsteroids: Novel progestational hormones

Zusammenfassung Die Synthese von 3, 17-Diacetoxy-17-Äthinyl-11-Methylestr-4-en (XII) wird beschrieben. Die Substanz besitzt besonders starke Antifertilitätseigenschaften, wie sie sonst nur Mischungen von Hormonen eigen sind, welche für die Humanfertilität benutzt werden, jedoch ohne deren Nebenwirkungen.     

Total synthesis of marine natural products without using protecting groups

The field of organic synthesis has made phenomenal advances in the past fifty years, yet chemists still struggle to design synthetic routes that will enable them to obtain sufficient quantities of complex molecules for biological and medical studies. Total synthesis is therefore increasingly focused on preparing natural products in the most efficient manner possible. Here we describe the preparative-scale, enantioselective, total syntheses of members of the hapalindole, fischerindole, welwitindolinone and ambiguine families, each constructed without the need for protecting groups--the use of such groups adds considerably to the cost and complexity of syntheses. As a consequence, molecules that have previously required twenty or more steps to synthesize racemically in milligram amounts can now be obtained as single enantiomers in significant quantities in ten steps or less. Through the extension of the general principles demonstrated here, it should be possible to access other complex molecular architectures without using protecting groups.     

A compact system of small planets around a former red-giant star

Planets that orbit their parent star at less than about one astronomical unit (1?AU is the Earth-Sun distance) are expected to be engulfed when the star becomes a red giant. Previous observations have revealed the existence of post-red-giant host stars with giant planets orbiting as close as 0.116?AU or with brown dwarf companions in tight orbits, showing that these bodies can survive engulfment. What has remained unclear is whether planets can be dragged deeper into the red-giant envelope without being disrupted and whether the evolution of the parent star itself could be affected. Here we report the presence of two nearly Earth-sized bodies orbiting the post-red-giant, hot B subdwarf star KIC 05807616 at distances of 0.0060 and 0.0076?AU, with orbital periods of 5.7625 and 8.2293 hours, respectively. These bodies probably survived deep immersion in the former red-giant envelope. They may be the dense cores of evaporated giant planets that were transported closer to the star during the engulfment and triggered the mass loss necessary for the formation of the hot B subdwarf, which might also explain how some stars of this type did not form in binary systems.     

A giant planet orbiting the 'extreme horizontal branch' star V 391 Pegasi

After the initial discoveries fifteen years ago, over 200 extrasolar planets have now been detected. Most of them orbit main-sequence stars similar to our Sun, although a few planets orbiting red giant stars have been recently found. When the hydrogen in their cores runs out, main-sequence stars undergo an expansion into red-giant stars. This expansion can modify the orbits of planets and can easily reach and engulf the inner planets. The same will happen to the planets of our Solar System in about five billion years and the fate of the Earth is matter of debate. Here we report the discovery of a planetary-mass body (Msini = 3.2M(Jupiter)) orbiting the star V 391 Pegasi at a distance of about 1.7 astronomical units (au), with a period of 3.2 years. This star is on the extreme horizontal branch of the Hertzsprung-Russell diagram, burning helium in its core and pulsating. The maximum radius of the red-giant precursor of V 391 Pegasi may have reached 0.7 au, while the orbital distance of the planet during the stellar main-sequence phase is estimated to be about 1 au. This detection of a planet orbiting a post-red-giant star demonstrates that planets with orbital distances of less than 2 au can survive the red-giant expansion of their parent stars.     

Production and characterization of hydrophobic zinc borate by using palm oil

Zinc borate (ZB) was synthesized using zinc oxide, boric acid synthesized from colemanite, and reference ZB as seed. The effects of reaction parameters such as reaction time, reactant ratio, and seed ratio on its yield were examined. Then, the effects of palm oil with solvents (isopropyl alcohol (IPA), ethanol, and methanol) added to the reaction on its hydrophobicity were explored. Reactions were carried out under determined reaction conditions with magnetically and mechanically stirred systems. The produced ZB was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and measurements of contact angle identified hydrophobicity. The results showed that hydrophobic ZB was successfully produced under determined reaction conditions. The change of process parameters influenced its yield and the usage of palm oil provided hydrophobicity.     

Effect of modifying agents on the hydrophobicity and yield of zinc borate synthesized by zinc oxide

The aim of this study was to synthesize zinc borate using zinc oxide, reference boric acid, and reference zinc borate (reference ZB) as the seed, and to investigate the effects of modifying agents and reaction parameters on the hydrophobicity and yield, respectively. The reaction parameters include reaction time (1–5 h), reactant ratio (H₃BO₃/ZnO by mass: 2–5), seed ratio (seed crystal/(H₃BO₃+ZnO) by mass: 0–2wt%), reaction temperature (50–120℃), cooling temperature (10–80℃), and stirring rate (400–700 r/min); the modifying agents involve propylene glycol (PG, 0–6wt%), kerosene (1wt%–6wt%), and oleic acid (OA, 1wt%–6wt%) with solvents (isopropyl alcohol (IPA), ethanol, and methanol). The results of reaction yield obtained from either magnetically or mechanically stirred systems were compared. Zinc borate produced was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and contact angle tests to identify the hydrophobicity. In conclusion, zinc borate is synthesized successfully under the optimized reaction conditions, and the different modifying agents with various solvents affect the hydrophobicity of zinc borate.