Raney Nickel Desulfurization Research Articles

�ber die Raney-Nickel-Entschwefelung schwefelhaltiger cyclischer Dipeptide

Raney nickel desulfuration of 3.6-epidithio-l-prolyl-l-proline anhydride andcis-3.6-bis(ethylthio)-l-prolyl-l-proline anhydride yields racemiccis-prolyl-proline anhydride, whereas after the reaction of 3-ethylthio-l-prolyl-l-proline anhydride no inversion of configuration was observed.—During the action of Raney nickel on one asymmetric center the configuration is only retained if steric factors inhibit an inversion.

The Facile Regeneration of the Cahbonyl Compounds from α-Ditsianes. the Reaction of Chlcramine-t with Substituted 1, 3-Ditsanes

Abstract Prior to 1965, when corey and Seebach reported the utility of 1,3-dithianes (I)as a synthetic intermediate, little interest had been shown in reactions of this class of compounds. A few instances in which spiro (m-dithianes) proved useful in synthesis had been reported. 2. Various methods for openig the m-dithiane ring have been employed including Raney nickel desulfurization 2b,c,bromine in acertic acid3a the NBS and NCS method3b. variations onthe method of Wolfrom (a mercuric salt and cadmium carbonate) developed for mercaptoles3c,various methods employing silver ion3d often in the presence of an oxidizing agent3e, boron trifluoride in the presance of mecuric oxide or mercuric acetate3f, and oxidation of the dithaine to the corresponding monosulfoxide followed by acid hydrolysis.3g With the Exception of Raney nickel desulforization, interest in cleavage of the d-dithiane ring centers around recovery of the carbonyl compound.

Synthesis of 17-aminopregn-4-ene-3, 20-dione

The synthesis of 17-aminopregn-4-ene-3, 20-dione ( 3b ) and several of its derivatives is reported here. Reaction of 16α, 17-acetylimino-3β-hydroxypregn-5-en-20-one ( 1 ) with potassium thiophenylate afforded 17-acetamido-3β-hydroxy-16β-phenylthiopregn-5-en-20-one ( 2a ). Raney nickel desulfurization of this compound and an Oppenauer oxidation yielded 17-acetamidopregn-4-ene-3, 20-dione ( 3a ). Preparation of 17-aminopregn-4-ene-3, 20-dione ( 3b ) was achieved via saponification of 17-acetamido-3, 3-ethylenedioxy-20 ϵ-hydroxypregn-5-en-3-one ( 4b ) followed by oxidation at C-20 and removal of the 3, 3-ethylenedioxy grouping. Evidence for the assigned structures is presented.

STEROIDS AND RELATED NATURAL PRODUCTS: XXXI. SELECTIVE REDUCTION OF ESTERS. PART B. CARBONATES

Direct reduction of several pivalate esters to neopentyl ethers has been accomplished with boron trifluoride – sodium borohydride. The utility of the reduction reaction was illustrated with esters Ic, IIb, and IVa. Under the same conditions, a selection (Id, IId, and IVa) of carbonate esters was found to be relatively resistant to reduction. In this respect, the carbonate esters resembled benzoate esters, and selective reduction of a ketone (IId) or another ester (IVa → IVb) in their presence was possible. For comparison, one xanthate ester (Ie) was allowed to react with boron trifluoride – sodium borohydride, and only the corresponding alcohol (Ia) was isolated. Raney nickel desulfurization of xanthate Ia was shown to provide alcohol Ia and hydrocarbon If as principal products.

THE PRODUCTS OF RANEY NICKEL DESULFURIZATION OF MONOTHIOKETALS.

THE PRODUCTS OF RANEY NICKEL DESULFURIZATION OF MONOTHIOKETALS.

Raney nickel desulfurization of 19-norsteroid ethylenethioketals : Synthesis of 4-estrene-2, 17-dione and related compounds

The synthesis of 4-estrene-2,17-dione (VIII) is described. Raney nickel desulfurization of the dihydroxy ethylenethioketal (IV) resulted in the dihydroxy compound (VI) with concomitant oxidation of the 2α-hydroxy function to give in low yield the corresponding 2-keto product (V). Further, it has been observed that Raney nickel desulfurization of the diacetoxy ethylenethioketal compound (III) under similar conditions eliminated the 2α-acetoxy group to give exclusively the homoannular diene (X), which on mild treatment with acid, isomerized to the heteroannular diene (XII).

Studies in Organic Sulfur Compounds. X.1 The Scope of the Raney Nickel Desulfurization of Cyclic Hemithioketals (1,3-Oxathiolanes and 1,3-Oxathianes)2

Studies in Organic Sulfur Compounds. X.¹ The Scope of the Raney Nickel Desulfurization of Cyclic Hemithioketals (1,3-Oxathiolanes and 1,3-Oxathianes)²

Studies in Organic Sulfur Compounds. VIII.1 Introduction of Oxygen in the Raney Nickel Desulfurization of Hemithioketals (1,3-Oxathiolanes)2

Studies in Organic Sulfur Compounds. VIII.¹ Introduction of Oxygen in the Raney Nickel Desulfurization of Hemithioketals (1,3-Oxathiolanes)²

Applications in the Carbohydrate Field of Reductive Desulfurization by Raney Nickel

This chapter discusses various applications in the carbohydrate field of reductive desulfurization by Raney nickel. Reductive desulfurization with Raney nickel is a reaction that requires but the simplest of techniques, is carried out under rather mild conditions, and affords relatively good yields; it is a standard and well-recognized reaction, having found use in practically all the various fields of organic chemistry. The chapter discusses Raney nickel's applications in sugar fields. Desulfurization carried out in aqueous alcohol has been observed to give rise to acetaldehyde; in view of the well-known dehydrogenating action of Raney nickel it seems likely that the solvent may play a part as a hydrogen donor in the reaction. In practice the sulfur-containing derivative is dissolved or suspended in a suitable solvent, treated with a sufficient quantity of Raney nickel, and either left at room temperature or heated under reflux, recovery of the product being effected by concentration of the liquid phase. The utility of Raney nickel desulfurization in solving problems of configuration in the sugar series is demonstrated in the ω-desoxyglycitol series. Reductive desulfurization with Raney nickel of the mercaptolysis products of streptomycin has supplied one of the keys to the elucidation of the structure and configuration of that antibiotic.