Investigations on sterols. 40. The synthesis of ring D substituted 9β,10α‐steroids

Abstract

S. J. Halkes et al. The synthesis of ring D substituted YP,lOcc-steroidsThe speed of evolution of wave packets initially confined to the initial cell into the final cell will essentially determine the wave-mechanical reaction rate. A conventional approximate treatment was carried out to obtain the absolute rate of proton migration in malonaldehyde mentioned in example iiz] of the preceding section.The rate constant was calculated to be -9.77 x 10" s-l over a wide range of ordinary temperatures. In this convention the evolution of wave packets was discussed within a one-dimensional motion along the IRC for which motions of the other freedoms are considered as providing the effective potential26.Such a convention is tractable based on the concept of the IRC which is clearly formulated in a closed form, and the whole process is made automatically calculable with the aid of the IRC-equations. Chemistry now assumes a certain logical character. Further experiments will be facilitated by such a logic as theoretical languages have induced in quantum chemistry, e.g. that of chemical reaction paths, which will be newly elucidated by the discovery of innovating experimental work. Professor Havinga has made a start in this direction. IntroductionInvestigations on sterols. 401*. The synthesis of ring D substituted 9P,lOa-steroids Abstract. The retro configuration (9p, IOU) was introduced into pregnane derivatives containing substituents at C(16) and/or C(17) by irradiation of a suitable 5,7-diene. In this way the title compounds became much more accessible than by the introduction of ring D substituents into 20-ketoretro-steroids. ' 39th Communication: J. Hartog, J. I. G. M. Wittelaar, L . Morsink and A . M . deWachter, J. Med. Chem. 15, 1292 (1972). S. J. Halkes, J. Hartog, L. Morsink and A . M . deWarhter, 79 in ethanol gave the desired 17u-hydroxy-9P, 10%-pregna-* Dedicated to Professor E. Hauinga as a token of our appreciation for his widespread achievements. ' P. H. Wirrsema, A . L. Loeh and J . Th. G. Ozierheek, J . Colloid Interface Sci. 22, 78 (1966).

Enhancement of Ultraviolet B Irradiation with a Photoluminescent Composite Film and Its Application in Photochemical Microfluidic Synthesis

“…As a matter of fact, the development of light sources is somewhat lagging behind that of the microfluidics, seriously hampering the wide application of continuous photochemical synthesis. For example, synthesis of steroidal drug intermediates such as vitamin D 2 , D 3 , and dihydrotestosterone, requires UVB irradiation (in the wavelength range of 280–315 nm) to initiate the photochemical reaction. , However, the emission wavelengths of common UV–LEDs are 365 and 405 nm. The emission intensity of UVB–LEDs (mainly at 305 nm) is only 5–10% compared to those of the 365 and 405 nm LEDs .…”