Synthesis of 6-oxy functionalized campest-4-en-3-ones: efficient hydroperoxidation at C-6 of campest-5-en-3-one with molecular oxygen and silica gel
摘要:
As a reference compound library for the investigation of biosynthesis of brassinosteroids, focused on a pathway from campesterol (1) to campestanol (2), 6-oxy functionalized campest-4-en-3-ones as well as campest-5-en-3-one (7) and campestane-3,6-dione were prepared from 1. Oxidation of 1 with pyridinium chlorochromate buffered by calcium carbonate gave 5-en-3-one (7) in 76% yield. Treatment of 7 with silica gel under an oxygen atmosphere in ethyl ether at room temperature produced efficient hydroperoxidation at the C-6 position to give 6 alpha-hydroperoxycampest-4-en-3-one and 6 beta-hydroperoxycampest-4-en-3-one in 34% and 49% yields, respectively. These compounds were converted to 6 alpha-hydroxycampest-4-en-3-one and 6 beta-hydroxycampest-4-en-3-one by reduction with triethyl phosphite. This provided the first example of the practical use of hydroperoxidation at C-6 of a Delta(5(6))-unsaturated 3-oxo-steroid with molecular oxygen and silica gel. On the other hand, oxidation of 1 with pyridinium chlorochromate in the absence of calcium carbonate gave campest-4-ene-3,6-dione in 64% yield. This compound was then converted in a highly stereoselective manner to campestane-3,6-dione with A/B trans ring junction by reduction with titanium (III) chloride in 85% yield.
Verfahren zur Herstellung von 21-Hydroxy-20-methyl-pregnan-Derivaten
申请人:SCHERING AKTIENGESELLSCHAFT
公开号:EP0002535A2
公开(公告)日:1979-06-27
Die Erfindung betrifft ein Verfahren zur Herstellung von 21-Hydroxy-20-methylpregnan-Derivaten der allgemeinen Formel
worin die Bindung ..... eine Einfachbindung oder eine Doppelbindung bedeutet, durch Fermentation von Zoo- oder Phytosterinen mit einer Kultur von Mycobacterium spec. NRRL B-3683 oder NRRL B-3805 oder seiner Varianten und Mutanten, welches dadurch gekennzeichnet ist, daß man die Fermentation bei einem pH-Wert von 6,0 bis 8,0 in Gegenwart von Borationen oder organischen Borverbindungen durchführt.
This disclosure is related to compositions and methods for treating dry dye disorders.
本公开涉及治疗干染病的组合物和方法。
Dwf5 mutants
申请人:——
公开号:US20020120111A1
公开(公告)日:2002-08-29
Dwarf5 (dwf5) mutants and methods of using the same are disclosed. The dwf5 polynucleotides can be used in the production of transgenic plants which display at least one dwf5 phenotype, so that the resulting plants have altered structure or morphology. Also described is the DWF5 genomic sequence.