Wolff-Kishner Research Articles

The tritylone protecting group: ether cleavage by Wolff–Kishner reduction

Alcohols react readily with 9-phenyl-9-hydroxy-anthrone to form substituted trityl ethers which can be readily cleaved by a specific base-catalysed reaction, the Wolff–Kishner reduction.

Synthesis of Bridged Steroids. VII. B-Norsteroids having a Gibbane B-C-D Ring System.(2). Synthesis of the 7-Deoxygibberellin Type Ring System

Synthesis of 3a-methylene-3β, 5β-ethano-B-nor-5β-androstane 6β-carboxylic acid (1) having a gibbane B-C-D ring system is described. 5β-Cyano-6β-vinyl-B-nor-5β-androstan-3-one (5), the starting material, was transfomed stereoselectively to 3α-tosyloxy-5β-(trans-β-formyl) vinyl-6β-vinyl-5β-androstane (22d), the key intermediate, by theeight-step synthesis. The latter, after selective ozonization was subjected to a newcyclization method involving Participation of 6β-hemiacetal function to afford 3β, 5β-etheno derivative (38), which on subsequent oxidation and the Wolff-Kishner reduction, led to the desired compound (1). Some attempted experiments for homologation atthe 5β-nitrile function are also described.

Utilization of Acyloins. I.

The synthesis and reduction of acyloins, both symmetrical and mixed, were studied. A series of C8C36 symmetrical and mixed acyloins could be obtained by the condensation of methyl esters of fatty acids under presence of metallic sodium dispersion in inert solvent such as xylene. From mass spectra of the mixed acyloins obtained above, it was found that the reaction of different kinds of fatty esters usually gave the mixed acyloin, in which the long chain had a carbonyl radical and the short chain contained a hydroxyl group. For example methyl butyrate and methyl caprinate reacted as follows : These acyloins were reduced to the corresponding unsymmetrical ketone by the Clemmensen method. In this reduction the hydroxyl group changed into methylene group leaving the carbonyl group unreacted as shown in the following example : The yields were 94%. The Clemmensen reduction of long chain ketone didn't give the corresponding hydrocarbons, while Wolff-Kishner reduction gave hydrocarbon in rather good yields.

Total Synthesis of dl-Cepharamine

The synthesis of dl-cepharamine (4) which is a member of hasubanan alkaloids, was accomplished after the model experiments started from 2-tetralone (5) were examined. The keto-lactam (30) was synthesized from 7, 8-dimethoxy-2-tetralone (7) via the keto-ester (27) or the keto-nitrile (53). Ketalization of the compound (30), followed by treatment under the Wolff-Kishner reaction condition caused by demethylation of a methoxyl group at C4 to result in the phenolic compound (63). Acetylation of the compound (63), followed by deketalization gave the keto-acetate (65). The diketone (67) was synthesized by bromination of the compound (65) with two equivalents of bromine, followed by heating with anhydrous sodium acetate in acetic acid. The target molecule, dl-cepharamine (4), was synthesized from the diketone (67) by successive treatments with BF3·ether-MeOH (monoenolmethylation), LiAlH4 reduction and oxidation with DMSO-phosphoric acid-DCC.

Novel transannular ring contraction from the attempted Wolff-Kishner reduction of 2,7-diphenylhexahydro-4-azepinone

Novel transannular ring contraction from the attempted Wolff-Kishner reduction of 2,7-diphenylhexahydro-4-azepinone

Studies on the Synthesis of the Steroids having an Arylcyclopropane Ring at Position 2 and 3. I

Wolff-Kishner reduction under Huang Minlon's condition of 2-arylmethylene-3-oxo-steroids were investigated, and following results were obtained. 1. Reaction of 2-benzylidene-5α-androstan-3-one (I) gave 2α, 3α-phenylmethylene-5α-androstane (II) and 5α-androstano [3, 2-c] pyrazole (IV). 2. Reaction of 2-benzylideneandrost-4-en-3-one (XXII) gave 2α, 3α-phenylmethyleneandrost-4-ene (XXIII), 5β-androstano [3, 2-c] pyrazole (XXIV), IV and androst-4-eno [3, 2-c] pyrazole (XXV). 3. Reaction of 2-benzylideneandrost-4, 6-dien-3-one (XXVI) gave 2α, 3α-phenylmethyleneandrost-4, 6-diene (XXVII) and XXV. Stereochemistry of products and reasonable explanation for the reaction process were presented.

Thiophen derivatives. Part XVIII. Synthesis of ββ-dimethyl fatty acids by hydrogenolysis of ω-thienylvaleric acids

ββ-Dimethyl fatty acids are conveniently synthesised by Friedel–Crafts acylation of thiophen and its homologues with ββ-dimethylglutaric anhydride, Wolff-Kishner reduction of the γ-thenoylbutyric acids obtained to the corres-ponding ω-thienylvaleric acids, and hydrogenolysis of the latter with Raney nickel.

The photochemistry of hydrazones: a photochemical wolff-kishner reduction (1)

The photochemistry of hydrazones: a photochemical wolff-kishner reduction (1)

Isolation of camelliagenin A, B and C from the fruits of Camellia japonica L

Camellia saponin was isolated from Camellia japonica L. The saponin was first hydrolyzed by alkali to give prosapogenin and was further hydrolyzed by hydrochloric acid to yield camelliagenin A, B and C. Camelliagenin A was derived from camelliagenin B by Wolff-Kishner reduction, and camelliagenin C also derived from camelliagenin B by LiAlH4 reduction. The physical and the chemical results suggested that these sapogenins belong to the pentacyclic triterpenes.

Synthesis and reactions of 3-benzo[b]thienyl-lithium

(Phenylthio)acetone on cyclodehydration with polyphosphoric acid or phosphorus pentoxide at 160—180° gave a mixture of 2-(15—18 mole%) and 3-methylbenzo[b]thiophen (82—85 mole%). Pure 3-Bromobenzo[b]thiophen was obtained in high yield by hydrolysis of 3-bromo-2-benzo[b]thienyl-lithium and by debromination of 2,3-dibromobenzo[b]thiophen with zinc dust and acetic acid. It was treated with n-butyl-lithium in ether at –70° to give 3-benzo[b]thienyl-lithium which was used to synthesize a number of 3-substituted benzo[b]thiophens. 1-(3-Benzo[b]thienyl) ethanol was oxidized with potassium dichromate and sulphuric acid to give 3-acetylbenzo[b]-thiophen and Wolff–Kishner reduction of benzo[b]thiophen-3-carboxaldehyde afforded 3-methylbenzo[b]thiophen.

Cyclopropano-steroids

The modified Wolff–Kishner reduction of 2-methylene- and substituted 2-methylene-Δ4-3-oxo-steroids in the 19-methyl and 19-nor series has been used to prepare 2α,3α-cyclopropano-steroids. The products obtained have been correlated with those resulting from the reaction of 1α-hydroxy-2-enes with methylene iodide/zinc–copper complex and of 1-oxo-2-enes with dimethylsulphoxonium methylide. The latter reagent has also been used to prepare some spirocyclopropano-steroids.

Synthesis of Cyperene, Cyperotundone, and Patchoulenone

Isopatchoul-9-en-5α-ol (VII) was hydrogenated using nickel catalyst in methanol to give 10α (H)-isopatchoulan-5α-ol (XII). Dehydration of the alcohol (XII) formed 10-epi-cyperene (IV) which on oxidation yielded 10-epi-cyperotundone (V). The alcohol (VII) was converted into 9α-acetoxy-10α (H)-isopatchoul-4-ene (XVII) via 10α (H)-isopatchoulane-5α, 9α-diol (XIV) by known methods. Hydrolysis of the unsaturated acetate (XVII) afforded 10α (H)-isopatchoul-4-en-9α-ol (XIX) which was oxidized to yield isopatchoul-4-en-9-one (XXI). Wolff-Kishner reduction of the ketone (XXI) furnished cyperene (III) which on oxidation gave cyperotundone (I) and patchoulenone (II).

Terpenoids—CV: Transformation products of alantolactones

Three lactones have been isolated from the roots of Inula racemosa and identified as alantolactone (I), isoalantolactone (II) and dihydroisoalantolactone (III) respectively. III was also prepared by partial reduction of II with NaBH 4, while on complete catalytic reduction, it formed tetrahydroalantolactone (IV). Amine adducts and methoxy derivs were prepared from II. The lactol VII and the diol VIII obtained from IV by controlled LAH reduction, when subjected to Huang-Minlon reduction, furnished the new crystalline monol, 8β-hydroxy eudesman (IX) and the diol VIII. The selinanone X, which is a convenient compound for the synthesis of 9-ketoeudesman (XX), was obtained from IX by oxidation with Jones' reagent. On Na/n-propanol reduction, X furnished the 8α-hydroxyeudesman (XIII) as a crystalline material. Lead tetraacetate oxidation of X yielded the rearranged keto acetate XXII. 9-Ketoeudesman (XX) was prepared from X via its furfurylidene deriv XXIII, followed by Wolff-Kishner reduction and ozonolysis. Tetrahedrocostic acid (XVIa) was obtained from the diol VIII by its oxidation to the keto-acid XV, followed by Wolff-Kishner reduction. The same sequence of reactions were carried out using III as the starting material to procure both the β- and α-unsaturated new crystalline monols (XXVII and XXIX) and the ketone XXVIII. A new interesting crystalline alcohol, 14-hydroxytetrahydroalantolactone (XXX) was prepared by hydroboration of III, oxidation of which with Jones's reagent yielded the lactone-acid XXXI.

Catalytic hydrogenolysis as an alternative to the wolff-kishner or clemmensen reduction methods for azabicyclic ketones

Catalytic hydrogenolysis as an alternative to the wolff-kishner or clemmensen reduction methods for azabicyclic ketones

The synthesis of an etiojervane analog of progesterone.

Abstract N-Acetyl-22, 27-iminojerva-5, 12-diene-3β, 23α-diol-11-one, prepared from jervine by Masamune et al. (J. Org. Chem., 29, 2282 (1964)), was submitted to a Birch reduction and then to a modified Wolff-Kishner reduction to yield 22, 27-iminojerv-5-ene-3β, 23α-diol. The compound was then degraded, according to the procedure by Johnson et al. (Tetrahedron Letters, 1963, 545), to a methyl ketone, which was then further oxidized by the Oppenauer method to give 17α-ethyletiojerv-4-ene-3, 20-dione.

The Effect of Dimethyl Sulfoxide on the Rate of the Wolff-Kishner Reaction of Benzophenone Hydrazone1

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Effect of Dimethyl Sulfoxide on the Rate of the Wolff-Kishner Reaction of Benzophenone Hydrazone1H. Harry Szmant and Mirta N. RománCite this: J. Am. Chem. Soc. 1966, 88, 17, 4034–4039Publication Date (Print):September 1, 1966Publication History Published online1 May 2002Published inissue 1 September 1966https://doi.org/10.1021/ja00969a025RIGHTS & PERMISSIONSArticle Views410Altmetric-Citations17LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (611 KB) Get e-Alerts Get e-Alerts

A synthesis of 2-alkyltryptamines and of 3,4-dihydro-β-carboline

Wolff–Kishner reduction of 1-substituted 3,4-dihydro-β-carbolines gives 2-(substituted methyl)-tryptamines. 3,4-Dihydro-β-carboline itself is conveniently prepared by treatment of N(b)-thioformyltryptamine with acid.

The chemistry of the tetracyclic diterpenoids—IV : The partial synthesis of (—)-kaur-16-en-19-oic acid from 7-hydroxykaurenolide

Hydrogenolysis of 7-oxokaurenolide and Wolff-Kishner reduction of the derived keto-acid gave (−)-kaur-16-en-19-oic acid.

A novel reaction course in the wolff-kishner reduction of dibenzylidene-acetone semicarbazone

The structure of a compound formed during Huang Minlon reduction of dibenzylideneacetone was shown to be 1,4-diphenyl-2,5-di(β-phenylethyl)-benzene (I). Irradiation of 1,4-diphenyl-2,5-di(β-phenylvinyl)-benzene (III) gave a mixture of 2 stereoisomers of 3,7-diphenyl-3,4,7,8-tetrahydro-1,2,5,6-dibenzanthracene (VII and VIII). Both of these are dehydrogenated to give 3,7-diphenyl-1,2,5,6-dibenzanthracene (IX).

A synthetic approach to the 9(10→ 19) [formula omitted]-pregnane system, involving carbocyclic ring cleavage during Wolff-Kishner reduction

A synthetic approach to the 9(10→ 19) [formula omitted]-pregnane system, involving carbocyclic ring cleavage during Wolff-Kishner reduction