A Novel Scheme for the Synthesis of 21-Acetoxypregna-1,4,9(11)-triene- 17α,21-diol-3,20-dione from 9α-Hydroxyandrostenedione

2020 ◽  
Vol 16 (5) ◽  
pp. 606-610
Author(s):  
Nguyen T. Diep ◽  
Luu D. Huy
Keyword(s):  
Double Bond ◽  
Chemical Synthesis ◽  
Economic Efficiency ◽  
Final Stage ◽  
Side Chain ◽  
Entire Process ◽  
Drug Synthesis ◽  
First Time

Background: Vietnam currently imports up to 90% of the pharmaceuticals it consumes and 100% of the steroid-based pharmaceuticals. The ability for efficient chemical synthesis of the steroids could create commercial opportunities to address this issue. Synthesis of 21-acetoxypregna-1,4,9(11)- triene-17α,21-diol-3,20-dione is considered a key intermediate in the scheme of steroidal drug synthesis. Previous synthesis attempts of such steroids (corticoids) introduce a double bond at C-1(2) in the final stage of synthesis, which delivers a poor yield and reduces the economic efficiency of the process. Objective: To study and develop a novel and effective method for the synthesis of 21-acetoxypregna- 1,4,9(11)-triene-17α,21-diol-3,20-dione. Methods: Using 9α-hydroxyandrostenedione as a substrate chemical synthesis was performed as follows: pregnane side chain construction at C-17 (acetylene method), introduction of C-1(2) double bond (using SeO2), epimerization of C-17 (via 17-ONO2 ester) and Stork’s iodination. Results: 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione was prepared from 9α- hydroxyandrostenedione with an improved yield compared to previous attempts. Conclusion: Here, 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione has been synthesized from 9α-hydroxyandrostenedione based on a novel, effective and commercially feasible scheme. The introduction of the C-1(2) double bond at an earlier stage of the synthesis has increased the economic efficiency of the entire process. For the first time, the indirect epimerization mechanism has been clarified along with the configuration of the C-17 stereo-center which has been confirmed using NOESY data.

A New pseudo-Alkaloid Taxane and a New Rearranged Taxane from the Needles of Taxus canadensis

2008 ◽  
Vol 63 (8) ◽  
pp. 1005-1011 ◽  
Author(s):  
Manli Zhang ◽  
Changhong Huo ◽  
Mei Dong ◽  
Ligeng Li ◽  
Françoise Sauriol ◽  
...  
Keyword(s):  
Double Bond ◽  
Nmr Spectroscopy ◽  
High Resolution ◽  
2D Nmr ◽  
Side Chain ◽  
2D Nmr Spectroscopy ◽  
Taxus Canadensis ◽  
First Time

A new taxane with an amino side chain on C-5 and a new 11(15→1)abeotaxane having a tetrahydrofuran ring along carbon atoms C-2, C-3, C-4, C-20 identified for the first time from the needles of the Canadian yew, Taxus canadensis. Their structures were characterized as 2α,7β ,9α,10β ,13-pentaacetoxy-11β -hydroxy-5α-(2´ -hydroxy,3'-N,N-dimethylamino-3´- phenyl)-propionyloxytaxa-4(20),12-diene (1) and 13α,20β -diacetoxy-5α,7β ,9α,10β -tetrahydroxy- 2α,20-epoxy-11(15→1)abeotaxa-11,15-diene (2) on the basis of 1D, 2D NMR spectroscopy and high-resolution FABMS analysis. Taxane 1 contains a rare C-12, C-13 double bond and a basic side chain, while taxane 2 bears a rare isopropenyl group at C-1.

scholarly journals Radical Dehalogenation and Purine Nucleoside Phosphorylase E. coli: How Does an Admixture of 2′,3′-Anhydroinosine Hinder 2-fluoro-cordycepin Synthesis

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 539
Author(s):  
Alexey L. Kayushin ◽  
Julia A. Tokunova ◽  
Ilja V. Fateev ◽  
Alexandra O. Arnautova ◽  
Maria Ya. Berzina ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Synthesis ◽  
Purine Nucleoside Phosphorylase ◽  
Purine Nucleoside ◽  
Preparative Synthesis ◽  
Nucleoside Phosphorylase ◽  
E Coli ◽  
First Time

During the preparative synthesis of 2-fluorocordycepin from 2-fluoroadenosine and 3′-deoxyinosine catalyzed by E. coli purine nucleoside phosphorylase, a slowdown of the reaction and decrease of yield down to 5% were encountered. An unknown nucleoside was found in the reaction mixture and its structure was established. This nucleoside is formed from the admixture of 2′,3′-anhydroinosine, a byproduct in the preparation of 3-′deoxyinosine. Moreover, 2′,3′-anhydroinosine forms during radical dehalogenation of 9-(2′,5′-di-O-acetyl-3′-bromo- -3′-deoxyxylofuranosyl)hypoxanthine, a precursor of 3′-deoxyinosine in chemical synthesis. The products of 2′,3′-anhydroinosine hydrolysis inhibit the formation of 1-phospho-3-deoxyribose during the synthesis of 2-fluorocordycepin. The progress of 2′,3′-anhydroinosine hydrolysis was investigated. The reactions were performed in D2O instead of H2O; this allowed accumulating intermediate substances in sufficient quantities. Two intermediates were isolated and their structures were confirmed by mass and NMR spectroscopy. A mechanism of 2′,3′-anhydroinosine hydrolysis in D2O is fully determined for the first time.

scholarly journals A Meningo-Leucoencephalomyelitis Resembling Visna in Dutch Zwoeger Sheep

1966 ◽  
Vol 3 (5) ◽  
pp. 401-411 ◽  
Author(s):  
A. A. Ressang ◽  
F. C. Stam ◽  
G. F. De Boer
Keyword(s):  
White Matter ◽  
The Netherlands ◽  
Final Stage ◽  
Chronic Condition ◽  
Cerebral Lesions ◽  
Terminal Stage ◽  
Icelandic Sheep ◽  
Close Relationship ◽  
Secondary Demyelination ◽  
First Time

Zwoegerziekte is a disease in Dutch sheep which morphologically closely resembles an Icelandic sheep disease, Maedi2. Chronic lung affection and emaciation are the principal symptoms of both diseases. Visna is another chronic condition in Icelandic sheep affecting mainly the C.N.S. A virus has been isolated from sheep affected with Maedi or Visna and a close relationship in properties has been found between both viruses. In two Dutch sheep autopsied in the final stage of Zwoegerziekte, lesions were present in the C.N.S., which histologically resembled those in Visna. Another sheep slaughtered at the municipal abattoir, with lung lesions characteristic for the terminal stage of Zwoegerziekte, exhibited early cerebral lesions resembling Visna. The lesions in the C.N.S. of these three sheep were meningitis and severe encephalomyelitis of the glial type affecting the white matter. Secondary demyelination was striking. Though Zwoegerziekte has been known for several decades in the Netherlands, the accompanying C.N.S. lesions are described for the first time.

Critical Review of Biotransformational Studies on Steroids by Using Culture of Cunninghamella blakesleeana

2021 ◽  
Vol 18 ◽  
Author(s):  
Azizuddin ◽  
Muhammad Iqbal ◽  
Syed Ghulam Musharraf
Keyword(s):  
Double Bond ◽  
Critical Review ◽  
Structural Modification ◽  
Bond Formation ◽  
Environmentally Friendly ◽  
Side Chain ◽  
Synthetic Compounds ◽  
Efficient Approach ◽  
Cunninghamella Blakesleeana ◽  
Different Strains

: For several decades, biotransformational studies on steroidal compounds have gained a lot of attention because it is an efficient approach for the structural modification of complicated natural or synthetic compounds with high regio-, chemo- and stereoselectivity at environmentally friendly conditions. This review summarizes the use of different strains of Cunninghamella blakesleeana for the biotransformation of sixteen steroids 1-16 into a variety of transformed products. The transformed products may be important as a drug or precursor for the production of important pharmaceuticals. The types of reactions performed by C. blakesleeana include hydroxylation, epoxidation, reduction, demethylation, oxidation, glycosidation, double bond formation, side-chain degradation, isomerisation and opening of an isoxazol ring, which would be difficult to produce by traditional synthesis.

Migration of the Double Bond in the Side Chain of Sterols with Iodine.

1970 ◽  
Vol 35 (12) ◽  
pp. 4145-4148 ◽  
Author(s):  
Nobuo Ikekawa ◽  
Yasushi Honma ◽  
Naoko Morisaki ◽  
Kiyoshi Sakai
Keyword(s):  
Double Bond ◽  
Side Chain

scholarly journals Multifunctional carbon nanotubes covalently coated with imine-based covalent organic frameworks: exploring structure–property relationships through nanomechanics

Nanoscale ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 1128-1137 ◽  
Author(s):  
Alicia Moya ◽  
Mercedes Hernando-Pérez ◽  
Marta Pérez-Illana ◽  
Carmen San Martín ◽  
Julio Gómez-Herrero ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Synthesis ◽  
Covalent Organic Frameworks ◽  
Structure Property ◽  
One Pot ◽  
Covalent Organic Framework ◽  
Mwcnt Surface ◽  
Structure Property Relationships ◽  
First Time ◽  
Organic Framework

Hybridization of imine-based covalent organic framework (COF-300) on oxidized MWCNT surface have been designed and succesfully developed for the first time in one-pot chemical synthesis.

1. Introduction and fundamental themes

2021 ◽  
pp. 1-11
Author(s):  
Paul S. Davies
Keyword(s):  
Economic Efficiency ◽  
Common Law ◽  
Contract Law ◽  
Private Law ◽  
Freedom Of Contract ◽  
Will Theory ◽  
First Time

This introductory chapter provides a brief overview of the fundamental elements of what constitutes a contract. It discusses undertakings or promises, deeds, written and oral promises, bargains, and bilateral and unilateral contracts. It concludes by examining some general themes in contract law to which reference will be made throughout the present title. These include freedom of contract, will theory, economic efficiency, objectivity in contract law, common law and equity, contract law within private law, and international influences on contract law. The outline provided in this chapter is necessarily brief; although some of the themes may seem a little difficult in the abstract, students approaching this subject for the first time should not be troubled. The concepts will become familiar and more easily understood through concrete examples provided in later chapters.

Extractives of Australian timbers. X. Autoxidation and other reactions of the conjugated side-chain of eberlin lactone. Isolation of a new isomer of ebelin lactone

1970 ◽  
Vol 23 (10) ◽  
pp. 2085 ◽  
Author(s):  
RA Eade ◽  
J Ellis ◽  
JS Shannon ◽  
HV Simes ◽  
JJH Simes
Keyword(s):  
Double Bond ◽  
Solid State ◽  
Osmium Tetroxide ◽  
Side Chain ◽  
Methyl Groups ◽  
Stepwise Manner ◽  
Terminal Double Bond ◽  
Conjugated Triene

The conjugated triene side-chain of ebelin lactone has been degraded in a stepwise manner using osmium tetroxide. A new isomer of ebelin lactone has been isolated from the sapogenin mixture and has been assigned the structure (9) in which the 25(26) double bond has the cis configuration. Autoxidation of ebelin lactone in the solid state yields a mixture from which three compounds have been isolated and identified; all three arise from oxidation of the side-chain at the terminal double bond and methyl groups.

Descriptions of the final instar larvae of three Chinese Idionyx species (Odonata: Anisoptera: Corduliidae)

Zootaxa ◽  
2019 ◽  
Vol 2716 (1) ◽  
pp. 53
Author(s):  
HAOMIAO ZHANG ◽  
XIAOLI TONG
Keyword(s):  
Final Stage ◽  
Biological Information ◽  
Generic Diagnosis ◽  
First Time

The larvae of Idionyx carinata Fraser, 1926, I. selysi Fraser, 1926 and I. victor Hämäläinen, 1991 are described and illustrated for the first time based on final stage larvae reared in laboratory. Idionyx selysi is newly recorded from China. A generic diagnosis and biological information are provided.

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