Sterols. XII. The Partial Synthesis of 4-Pregnene-17α,20,21-triol-3-ones and Reichstein's Substance E<sup>1</sup>

Julian, Percy L.; Meyer, Edwin W.; Karpel, William J.; Cole, Wayne

doi:10.1021/ja01149a026

Cited by 22 publications

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“…Fractions 10-12 contained two compounds (infrared bands at 6.1 and 8-10 µ), evidenced by gas chromatography. Fractions 13-24 contained a single compound (infrared bands at 6.1, 8.4, and 12.8 µ), and fractions [25][26][27][28][29][30][31][32][33][34][35] contained another compound (infraredbands in the 9-10-µ region), which, after rechromatography, weighed 1.2 g. (5.6%). The infrared spectrum of this compound was identical with that of the diethyl ketal of 4-Z-butylcyclohexanone (vide infra).…”

Section: Methodsmentioning

confidence: 99%

The Products of Raney Nickel Desulfurization of Monothioketals¹

Eliel¹,

Krishnamurthy²

1965

J. Org. Chem.

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VOL. 30 carbonyl peak at approximately 5.7 employing a Perkin-Elmer Model 21 recording infrared spectrophotometer. This method was chosen after repeated attempts to use the iodometric method of Silbert and Swernl* proved unreliable with the later stages of a kinetic run.The perester solutions in carbon tetrachloride were degassed, then sealed in thoroughly cleaned ampoules prepared from 9-mm. Pyrex tubing. The samples were immersed into an electrically heated oil bath controlled to f0.2' by means of a Fisher-Serfass electronic relay. An equilibration time of 2 min. was allowed for the samples to reach bath temperature. At definite time intervals an ampoule was removed and immediately quenched by immersion in ice-water. The ampoules were stored a t -70' until the completion of the kinetic run, then they were broken, and the sample was transferred directly to an infrared cell.The rate constants determined are the average of at least two runs and are summarized in Table I V .The energies of activation were calculated from a plot of the log of the rate constant os. the reciprocal of the absolute temperature employing the method of least squares to determine the slope. The entropies of activation were calculated by the method of Foster, Cope, and Daniels.% (20) E . G. Foster, A.Desulfurization of the two stereoisomeric 4-t-b11tylcyclohexanone ethylene monothioketals (I) with Raney nickel in benzene at room temperature gave 4-t-butylcyclohexanone (53-55%), cis-4-t-butylcyclohexyl ethyl ether (12-14%), 4-t-butylcyclohexanone diethyl ketal (6-11%), 4-t-butylcyclohex-1-enyl ethyl ether (16%), and 4-t-butylcyclohexene (7-12%), in addition to much ethane and a little ethylene. Product composition waa independent of the stereochemistry of the starting material. Similarly, the two 3-cholestanone ethylene monothioketals (11) gave 3-cholestanone (43-4770), 3a-ethoxycholestane (11-127?), 3-ethoxy-2-cholestene (20-21%), 3-cholestanone diethyl ketal (7-8%), and 2-cholestene ( P 5 % ) . The two isomers of 4-t-butylcyclohexanone trimethylene monothioketal (111) gave 4-~-butylcyclohexanone ( 47-48y0), cis-4-t-butylcyclohexyl n-propyl ether (1270), 4-1-butylcyclohex-1-enyl n-propyl ether ( 16y0), 4-t-butylcyclohexanone di-n-propyl ketal (7%), and 4-t-butylcyclohexene (7%). The recovery of the three-carbon fragment as propane (with traces of propylene and cyclopropane) was low in this case.

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Section: Methodsmentioning

confidence: 99%

The Products of Raney Nickel Desulfurization of Monothioketals¹

Eliel¹,

Krishnamurthy²

1965

J. Org. Chem.

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“…Steroid 4-ene-3-ones may be converted to alkyl dienol ethers by heating a solution of the unsaturated ketone in benzene-alcohol with a trialkyl ortho formate and hydrogen chloride (99,146,242,253), or by allowing a solution of the unsaturated ketone in dioxane-trialkyl orthoformate containing a little sulfuric or perchloric acid to stand at room temperature (90,154,193,262,305). Sufficient tertiary amine to neutralize the acid catalyst is usually added to the reaction mixture prior to isolation of the product.…”

Section: Conversion Of 3-keto-j 4 -Steroids To 3-alkoxy-j 3 > 5 -Stermentioning

confidence: 99%

Reactions of Ortho Esters Which Result in Carbon-Oxygen and Carbon-Halogen Bond Formation

1970

Carboxylic Ortho Acid Derivatives - Preparation and Synthetic Applications

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In this chapter are considered reactions of trialkyl orthocarboxylates and tetraalkyl orthocarbonates which result in the formation of new carbonoxygen or carbon-halogen bonds. In most of these reactions the ortho ester (or an alkoxycarbonium ion derived from it) functions as an alkylating agent.Many of these reactions are useful synthetic tools. These include formation and hydrolysis of cyclic ortho ester derivatives of diols and triols (which serve to protect the hydroxyl groups of the polyols, and provide means for their mild monoacylation), alkylation of phenols, enols and acids (to form ethers and esters), and conversion of carbonyl compounds to acetals and ketals. Other reactions, such as the alkylation of halogens by ortho esters, are of only limited synthetic utility, while still others, such as the acidcatalyzed hydrolyses of ortho esters, are of interest primarily because of the light they shed on the mechanisms of reactions of ortho esters with nucleophilic reagents.

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Ethylene Oxides

Rosowsky¹

1964

Chemistry of Heterocyclic Compounds: A Series of Monographs

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Sterols. XII. The Partial Synthesis of 4-Pregnene-17α,20,21-triol-3-ones and Reichstein's Substance E¹

Cited by 22 publications

References 1 publication

The Products of Raney Nickel Desulfurization of Monothioketals¹

The Products of Raney Nickel Desulfurization of Monothioketals¹

Reactions of Ortho Esters Which Result in Carbon-Oxygen and Carbon-Halogen Bond Formation

Ethylene Oxides

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Sterols. XII. The Partial Synthesis of 4-Pregnene-17α,20,21-triol-3-ones and Reichstein's Substance E1

Cited by 22 publications

References 1 publication

The Products of Raney Nickel Desulfurization of Monothioketals1

The Products of Raney Nickel Desulfurization of Monothioketals1

Reactions of Ortho Esters Which Result in Carbon-Oxygen and Carbon-Halogen Bond Formation

Ethylene Oxides

Contact Info

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Sterols. XII. The Partial Synthesis of 4-Pregnene-17α,20,21-triol-3-ones and Reichstein's Substance E¹

The Products of Raney Nickel Desulfurization of Monothioketals¹

The Products of Raney Nickel Desulfurization of Monothioketals¹