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ChemicalBook CAS DataBase List Prednisone
53-03-2

Prednisone synthesis

10synthesis methods
Prednisone is 17α,21-dihydroxypregna-1,4-dien-3,11-20-trione (27.1.31). Prednisone differs from cortisone in the presence of an additional double bond between C1 and C2. There are various ways of synthesizing it. In one of these, as is in the case when synthesizing cortisone, it is synthesized from dihydrocortisone acetate. However, in the given example, this compound undergoes dibromination by molecular bromine, giving 2,4-dibromo-derivative of dihydrocortisone 27.1.30. Dehydrobromination with 3,5-lutidine, followed by subsequent hydrolysis of the acetyl group using potassium bicarbonate gives the desired prednisone (27.1.31). Prednisone is also synthesized by microbiological dehydrogenation of cortisone.

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Yield:53-03-2 94%

Reaction Conditions:

with Rhodococcus coprophilus DSM 43347 in dimethyl sulfoxide at 30; for 24 h;Green chemistry;regiospecific reaction;Reagent/catalyst;

Steps:

3.3. Semi-Preparative Biotransformation Protocol

General procedure: The biotransformations showing additional spots other than the starting material were repeated on a semipreparative scale (200 mL) in order to isolate the products. For each of the selected Rhodococcus strains, a loopful of bacterial cells cultured on PCA was transferred to 50 mL Erlenmeyer flasks containing 20 mL of sterile PCB medium and incubated at 30 °C and 110 rpm in an orbital shaker for 48 h. The whole culture was introduced into a 500 mL Erlenmeyer flask containing 200 mL of sterile PCB, and after 48 h incubation at 30 °C and 110 rpm, the substrate (0.2 g) in DMSO (2 mL) was added and the culture was maintained in the same conditions for a maximum of 72 h. All tests were carried out in triplicate for statistical significance. A blank sample was also incubated containing all the reagents but no bacteria. The reaction course was monitored by withdrawing samples (1 mL) every 24 h up to 72 h of reaction, and the semipreparative reactions were followed by TLC analysis and stopped when the higher conversion was reached. TLC analysis was performed using 1 ml of sample taken every 24 h from the flask in which the reaction was conducted. The sample was subsequently subjected to centrifugation, extraction with ethyl acetate, and immediately analyzed using TLC on silica gel using ethyl acetate as an eluent, following the same protocol used in the screening procedure. The cells were removed by centrifugation (5242 RCF, 20 min) and the supernatant was extracted with ethyl acetate (3 × 80 mL). The organic layer was dried over anhydrous Na2SO4, the solvent was evaporated, and the crude mixture was purified on a chromatographic column (silica gel, ethyl acetate/cyclohexane 50/50 as an eluent). The biotransformation yields were obtained by working out the percentage of the ratio between the moles of the product obtained compared to the moles of the administered substrate.

References:

Costa, Stefania;Fantin, Giancarlo;Semeraro, Bruno;Summa, Daniela;Zappaterra, Federico [Molecules,2020,vol. 25,# 9]

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