“Enamine” Derivatives of Steroidal Carbonyl Compounds. I

Herr, Milton E.; Heyl, Frederick W.

doi:10.1021/ja01134a048

Cited by 76 publications

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“…Aldehyde 1a should be a more promising candidate for inversion of configuration at C(20) by synthesis of the enolate or the corresponding enamine. After acid hydrolysis [7] of aldehyde 1a, only a 1 : 2 mixture 1a/1b ((R/S); determined by 1 H-NMR) could be obtained. The same ratio was determined after acid hydrolysis of the enamine 22-(piperidin-1-yl)-23,24-dinorchola-4,20(22)-dien-3-one, prepared from 1a according to Herr and Heyl [7].…”

mentioning

confidence: 99%

Synthesis of Methyl (20R,22E)- and (20S,22E)-3-Oxochola-1,4,22- trien-24-oate

Linker¹,

Kreiser²

2002

HCA

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Dedicated to the memory of V. Cerny Methyl (22E)-3-oxochola-1,4,22-trien-24-oate (4; C 25 H 34 O 3 ) is a naturally occurring steroid with unknown configuration at C(20). Starting from the (20S)-3-oxo-23,24-dinorchol-4-en-22-al (1a), we prepared both diastereoisomeric methyl esters 4a and 4b by a three-step procedure (Scheme). In the case of 4b, the initial epimerization of aldehyde 1a was followed by completion of the sequence and then separation via fractional crystallization to afford pure (20R)-methyl ester 4a and its (20S)-diastereomer 4b. Only the analytical data of the (20S)-compound 4b were in good agreement with those reported for the natural product.

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confidence: 99%

Synthesis of Methyl (20R,22E)- and (20S,22E)-3-Oxochola-1,4,22- trien-24-oate

Linker¹,

Kreiser²

2002

HCA

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“…Herr and Heyl [32,33] found that better yields of enamines from ketones can be obtained by the azeotropic removal of water in the presence or absence [32,33] of acid catalysts [12a, b, 34, 35] Less successful was the attempt to extend the reaction to ketones.…”

Section: Omentioning

confidence: 99%

“…where the catalyst is K 2 C0 3 [20], CaO [31], BaO [36], /?-CH 3 -C 6 H 4 S0 3 H [34,35], Dowex 50 [37], acetic acid [38], or montmorillonite catalyst KIO [39]; and the solvent for azeotropic removal of water is C 6 H 6 [32,33], CH 3 -C 6 H 5 [12a, b] or (CH 3 ) 2 C 6 H 4 [12a, b]. Solvents for the nonazeotropic removal of water are methanol [40], acetone [41], pyridine [40], dimethylformamide [40], or tetrahydrofuran [41].…”

Section: R' Hmentioning

confidence: 99%

“…(31) The enamine-imine tautomerism in the indolenine system [195]. (32) Reaction of chloramines and acetylenes to give chloroenamine inter mediates [196].…”

Section: -7 Reduction Of L-methyl-l 9 234-tetrahydroquinoline To mentioning

confidence: 99%

“…

The chemistry of enamines has been described in several reviews [25][26][27][28][29] and in a recent monograph [30].

[32,33] found that better yields of enamines from ketones can be obtained by the azeotropic removal of water in the presence or absence [32,33] of acid catalysts [12a, b, 34, 35]

Condensation of Secondary Amines with Aldehydes and Ketones…”

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Enamines

1971

Organic Chemistry: A Series of Monographs

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The chemistry of enamines has been described in several reviews [25][26][27][28][29] and in a recent monograph [30]. CONDENSATION REACTIONS A. Condensation of Secondary Amines with Aldehydes and KetonesThe most widely used method for preparing enamines involves the conden sation of aldehydes and ketones with secondary amines (Eq. 6). In 1936, Mannich and Davidsen [31] were the first to describe the reaction of secondary amines with aldehydes in the presence of anhydrous potassium carbonate at approximately 0°C to give enamines (Eqs. 6, 7). R-CH 2 CH=0 + 2HNR , R-C-CH R' + HNRJ II oMannich and Davidsen [31] also reported that most of the aldehydes were first converted to a diamino intermediate which on distillation afforded the enamine. Less successful was the attempt to extend the reaction to ketones. Only with the use of calcium oxide at elevated temperatures were the enamines directly obtained, but in poor yields. Herr and Heyl [32,33] found that better yields of enamines from ketones can be obtained by the azeotropic removal of water in the presence or absence [32,33] of acid catalysts [12a, b, 34, 35]

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Hormones, Adrenal‐Cortical

Avery

Woolfrey

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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Adrenal‐cortical hormones, following the introduction of cortisone and hydrocortisone nearly a half‐century ago, have continued to be the drug of choice in treatment of afflictions ranging from skin rash to severe acute inflammatory disorders and are now included in many other therapeutic regimes. The adrenal cortex releases both mineralocorticoids and glucocorticoids; the latter influence carbohydrate and protein metabolism, and the former regulate sodium reabsorption in the kidney. Moreover, corticosteroids and their metabolites were early noted to possess powerful antiinflammatory and immunomodulatory properties, leading to a massive increase in research in the area of steroid synthesis and physiology, imparting great impetus to the development of synthetic steroids. These exhibited activities far greater than those of the natural hormones, thereby opening the way to development of many more active antiinflammatory agents. Corticosteroids are commonly used as topicals for the suppression of symptoms, including inflammation. Though they are rarely considered curative, many diseases respond well symptomatically to treatment with them, eg, liver disease, acute spinal cord injury, organ transplants, GI diseases, and dermatologic diseases, among others. Mineralocorticoid therapy is less common. Progesterone is the key intermediate in both mineralocorticoid and glucocorticoid biosynthesis. Cortisol and aldosterone are results of oxidations of progesterone. The major metabolic transformations of the adrenal cortical hormones generally follow the metabolism of cortisol. The effects of adrenal‐cortical steroids are thought to result from their interaction with intracellular receptors; these are the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR). The primary structure of the GR has been identified as a 795 residue protein; a significant amount of 3‐D structure elucidation of the GR has been made. The process by which adrenocortical steroids impart their action is based on the action of the steroid on a receptor (GR or MR). The use of glucocorticoids leads to antiinflammatory effects by first controlling gene expression, which subsequently leads to the synthesis and/or suppression of inflammation regulatory proteins. Microorganisms are available which transform progesterone and cortisone into steroids. These steroids surpass their parent hormones in antirheumatic and antillergic activity and produce lower levels of side effects. When tested in patients with rheumatoid arthritis, fludrocortisone acetate proved to be 10 times more potent than hydrocortisone acetate. Triamcinolone possesses high glucocorticoid and antiinflammatory activity and is almost entirely devoid of salt‐retaining activity. 2α‐Methyl‐9α‐fluorocortisol has been reported to show enhanced glucocorticoid activity and greatly enhanced mineralocorticoid activity, surpassing aldosterone in sodium‐retaining and potassium‐excreting potency. Hyperaldosteronism is accompanied by elevation of blood pressure and can be treated with an aldosterone antagonist, eg, spironolactone. Antagonists of glucocorticoid and mineralocorticoid activity have found increased use in the treatment of hypertension. The most clinically useful GR antagonist is RU‐486.

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“Enamine” Derivatives of Steroidal Carbonyl Compounds. I

Cited by 76 publications

References 0 publications

Synthesis of Methyl (20R,22E)- and (20S,22E)-3-Oxochola-1,4,22- trien-24-oate

Synthesis of Methyl (20R,22E)- and (20S,22E)-3-Oxochola-1,4,22- trien-24-oate

Enamines

Hormones, Adrenal‐Cortical

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