16-dehydropregnenolone Acetate Research Articles

Regio- and stereoselective thermal cycloaddition of α-aryl- N-phenylnitrones to 16-dehydropregnenolone acetate: π-facial selective addition of the minor rotamers of the nitrones

Thermal cycloaddition of α-aryl- N-phenylnitrones to the C16C17 π-bond in 16-dehydropregnenolone-3β-acetate ( 1) involves only the minor rotamer ( E-form) of the nitrones and occurs regio-, stereo- and π-facial-selectively to afford steroido[16,17- d]isoxazolidines ( 3) in high yield.

Stereoselective synthesis of a new hexanor(C23–C28)castasterone-20,22-ethyl diether from 16-dehydropregnenolone acetate and its plant growth promoting activity

Stereoselective synthesis of a new hexanor(C23–C28)castasterone-20,22-ethyl diether 22 has been achieved in sixteen steps from cheap and readily available 16-dehydropregnenolone acetate. This new brassinosteroid has shown typical brassin activity in mung bean epicotyl bioassay.

Stereoselective synthesis of (22R, 23R, 24S)-3β-hydroxy-5-ene-22,23-dihydroxy-24-methyl-cholestane: A brassinolide intermediate from 16-dehydropregnenolone acetate.

A new synthesis of the important aldehyde 1 from easily available 16-Dehydropregnenolone acetate (16-DPA) in high yield is described. The aldehyde 1 is converted to trio] 24, involving a stereoselective generation of all the four chiral centers in the brassinolide side chain. The important features of this synthesis is stereospecific generation of the acetate 14 through ene reaction using three different catalysts as well as regioselective wittig reaction on the acetoxy aldehyde 20. Conversion of triol 24 to brassinolide is known, hence this constitutes a formal total synthesis of brassinolide.

Reduction of Steroidal Ketones and Enones by Sodium Dithionite in Presence of Phase Transfer Catalyst

Abstract Sodium dithionite has been effectively used in the reduction of steroidal ketones and enones with remarkable selectivity and high yields under phase transfer catalysis (PTC) conditions to give alcohols and ketones respectively. An application of these selectivities is demonstrated by reducing an important steroid intermediate 16-dehydropregnenolone acetate to pregnenolone acetate in very high yields.

ChemInform Abstract: Simplified Preparation of 16‐Dehydropregnenolone Acetate.

ChemInformVolume 21, Issue 46 Natural Products ChemInform Abstract: Simplified Preparation of 16-Dehydropregnenolone Acetate. I. V. MICOVIC, I. V. MICOVIC Fac. Chem., Univ., 11001 Belgrade, YugoslaviaSearch for more papers by this authorM. D. IVANOVIC, M. D. IVANOVIC Fac. Chem., Univ., 11001 Belgrade, YugoslaviaSearch for more papers by this authorD. M. PIATAK, D. M. PIATAK Fac. Chem., Univ., 11001 Belgrade, YugoslaviaSearch for more papers by this author I. V. MICOVIC, I. V. MICOVIC Fac. Chem., Univ., 11001 Belgrade, YugoslaviaSearch for more papers by this authorM. D. IVANOVIC, M. D. IVANOVIC Fac. Chem., Univ., 11001 Belgrade, YugoslaviaSearch for more papers by this authorD. M. PIATAK, D. M. PIATAK Fac. Chem., Univ., 11001 Belgrade, YugoslaviaSearch for more papers by this author First published: November 13, 1990 https://doi.org/10.1002/chin.199046289Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume21, Issue46November 13, 1990 RelatedInformation

Simplified Preparation of 16-Dehydropregnenolone Acetate

A simplified, one-pot preparation of 16-dehydropregnenolone acetate (4) from diosgenin (1) using normal pressure and a much reduced temperature compared to known procedure was developed in an overall yield varied from 65 to 69 %. The method lends itself very well to industrial scale methodology.

Observance of the endo principle in the Diels-Alder reactions of A65-20-ketosteroids

The condensation of 16-dehydropregnenolone acetate with piperylene at 14 kbar showed that the Diels-Alder reaction of Δ16-20-ketosteroids with butadienes at high pressure, as in the case of catalytic conditions, proceeds in accord with the endo principle for this reaction.

Transformed steroids Communication 152. Photocycloaddition of 1-pentyne to 16-dehydropregnenolone acetate

The regio- and stereospecific [2 + 2]-photoaddition of 1-pentyne to 16-dehydropregnenolone acetate has been used to obtain 2′-propyl-16α,17α-cyclobuteno- and cyclobutanoprogesterones.

Diels-Alder reaction of 16-dehydropregnenolone acetate with 1,2-dimethylenecyclobutane

16-Dehydropregnenolone acetate undergoes condensation with 1,2-dimethylenecyclobutane in the presence of a Lewis acid to form a 16α,17α-monoadduct, namely, 3′,4′-ethano-16α,17α-cyclohex-3′-enopregn-5-en-3β-ol-20-one acetate.

Metabolism of steroid acetates by Streptomyces albus

Fermentation of 16-dehydropregnenolone acetate ( 1a) with Streptomyces albus yielded 16-dehydropregnenolone ( 1b) and 16-dehydroprogesterone ( IIa). Similar incubation of pregnenolone acetate ( Ic) with the strain afforded pregnenolone ( Id), progesterone ( IIb) and 20α-hydroxy progesterone ( IIc) while dehydroepiandrosterone acetate ( IIIa) under the conditions was converted to dehydroepiandrosterone ( IIIb), androstenedione ( IVa) and testosterone ( IVc). The strain was also capable of converting testosterone acetate ( IVb) having the 17-acetoxy function in the 5-membered d-ring to testosterone ( IVc) and androstenedione ( IVa). All the products were identified by the application of various chemical and spectrometric techniques.

Cycloaddition of diazoacetic ester to 16-dehydropregnenolone acetate under high pressure

The cycloaddition of ethyl diazoacetate to 16-dehydropregnenolone acetate under high pressure makes it possible to obtain, along with the known pyrazoline, the primary reaction product, namely the Δ1-pyrazoline.

Transformed steroids

As a continuation of studying [2, 3] the synthesis and chemical transformations of transformed steroids that contain an additional carbocycle or heterocycle in the 16, 17 position, we studied the reaction of the N-hydroxymethyland N-chloromethylbenzamides with the 16dehydropregnenolone acetate. It is known that the N-chloromethylamides react with various alkenes in the presence of anhyd. SnCI4 to give cyclic products, and specifically dihydro1,3-oxazines. This reaction is regarded as being the 1,4-polar cycloaddition of the amidomethylium ion to the double bond of the alkene [4]. When applied to the A16-20-ketosteroids this transformation can lead to pentacyclic steroids that contain the oxazine ring in the 16, 17 position.

Histochemical localization of Δ 5-3 β-hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase in the testis of Indian skipper frog Rana cyanophlyctis (Schneider)

The distribution of Δ 5-3 β-hydroxysteroid dehydrogenase (Δ 5-3 β-HSDH), glucose-6-phosphate dehydrogenase (G-6-PDH), TPNH- and DPNH-diaphorases were histochemically studied in the testis of skipper frog ( Rana cyanophlyctis) throughout the year. Pregnenolone, 17α-hydroxypregnenolone, 16-dehydropregnenolone acetate, dehydroepiandrosterone (DHA), and etiocholanolone were used as the substrates for the demonstration of Δ 5-3 β-HSDH activity, which occurs mainly in the interstitial Leydig cells and also in the columnar cells of Sertoli, indicating their probable role in steroidogenesis. Both G-6-PDH and the TPNH-diaphorase show a distribution similar to that of Δ 5-3 β-HSDH but give intense reaction, whereas the distribution of DPNH-diaphorase is ubiquitous. No appreciable seasonal variation in the distribution of these enzymes has been observed. The significance of these findings and the substrate specificity of Δ 5-3 β-HSDH in the frog testis has been discussed.

Addition of tri(2-methylallyl) borane to 16-dehydropregnenolone acetate

The reaction of 16-dehydropregnenolone acetate with tri(2-methylallyl)borane proceeds by 1,2-addition of a boron-allyl fragment to the 20-carbonyl group of the steroid molecule.

Bromination of a reformatsky adduct to 16-dehydropregnenolone acetate

Bromination of a reformatsky adduct to 16-dehydropregnenolone acetate

Continuous permanganate oxidation of 16-dehydrosteroids

16-Dehydroprogesterone, 16-dehydropregnenolone acetate and 16-dehydro-A-norprogesterone have been converted to the corresponding 16α,17α-dihydroxy derivatives in high yield by oxidation with potassium permanganate as a continuous-flow process. The details of the technique and a simple laboratory continuous reactor are described.