The transformation of levopimaric acid into warburganal

The chiral resin acid levopimaric acid (1), isolated from pine oleoresin, is used as a starting material for the synthesis of (−)-warburganal (2). The synthesis proceeds via the endoperoxide of methyl levopimarate, which after ozonolysis, protection of the resulting aldehyde function, reduction, and treatment with sodium methoxide provides the tetranorditerpenoid 12a. The hemiacetal 12a is then transformed to a mixture of hemithioacetals. At this point the carbomethoxyl group at C-4 is reduced to a methyl group, and then a C-11, C-12 double bond is introduced. Ozonolysis followed by elimination of formic acid provides a mixture of olefins (27) that is hydroxylated at C-9. Removal of the protecting group then gives (−)-warburganal (2). The sequence requires 15 steps and the overall yield from levopimaric acid to warburganal is 2.7%.

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Some Analogs of 4-(2',4'-Difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic Acid: Synthesis and Antiinflammatory Activity

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19951026 ◽

1995 ◽

Vol 60 (6) ◽

pp. 1026-1033 ◽

Cited By ~ 8

Author(s):

Miroslav Kuchař ◽

Václav Vosátka ◽

Marie Poppová ◽

Eva Knězová ◽

Vladimíra Panajotovová ◽

...

Keyword(s):

Double Bond ◽

Antiinflammatory Activity ◽

Acid Synthesis ◽

Reaction Conditions ◽

Methyl Group ◽

Oxobutanoic Acid

Analogs of 4-(2',4'-difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic acid (I, flobufen), containing a double bond (II, IV, V, VII, VIII) or a methyl group in position 3 (VI) were prepared. Their antiinflammatory activity was evaluated and compared with that of flobufen. None of the mentioned analogs reached the activity of the standard. Isomerization of the unsaturated derivatives is connected with a shift of the double bond, Z-E transformation or lactonization. Reaction conditions and spectra of the compounds prepared are described.

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Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

Canadian Journal of Chemistry ◽

10.1139/v85-166 ◽

1985 ◽

Vol 63 (4) ◽

pp. 993-995 ◽

Cited By ~ 8

Author(s):

Kazimierz Antczak ◽

John F. Kingston ◽

Alex G. Fallis

Keyword(s):

Double Bond ◽

Methyl Ester ◽

Total Synthesis ◽

Ring System ◽

Diels Alder ◽

Exocyclic Double Bond ◽

Total Syntheses ◽

Methyl Group ◽

Secondary Hydroxyl ◽

Selective Hydrogenolysis

Stereoselective total synthesis of (±)-sinularene and (±)-5-epi-sinularene are described. The sequence employs a "blocked" cyclopentadiene in which the cyclopropane unit also serves as a latent methyl group. Thus intramolecular [4 + 2] cycloaddition of the substituted methyl spiro[2.4]hepta-4,6-dien-1-yl)-2-pentenoate 11 affords 5-benzyloxy-6-isopropyl-8-carbomethoxytetracyclo[5.4.01,7.02,4.02,9]undec-10-ene (12) which after selective hydrogenolysis generates the tricyclo[4.4.01,6.02,8]decane (sinularene) ring system. Removal of the secondary hydroxyl function (Ph3P/CCl4/CH3CN; H2/Pd/C), reduction of the methyl ester (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550 °C) completes the synthesis of (±)-sinularene in 14 steps from cyclopentadiene. A parallel series of reactions employing the isopropyl epimer of 12 affords (±)-5-epi-sinularene.

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Oxidative decarboxylation of the 3-methyl-2-carboxynorbornanes with lead tetraacetate

Canadian Journal of Chemistry ◽

10.1139/v76-172 ◽

1976 ◽

Vol 54 (8) ◽

pp. 1222-1225 ◽

Cited By ~ 3

Author(s):

J. B. Stothers ◽

K. C. Teo

Keyword(s):

Carboxylic Acids ◽

Lead Tetraacetate ◽

Starting Material ◽

Oxidative Decarboxylation ◽

Methyl Group

The mixtures of isomeric acetates produced by oxidative decarboxylation of the four 3-methyl-norbornane-2-carboxylic acids with lead tetraacetate in benzene have been characterized. The composition of these products depends primarily on the configuration of the methyl group in the starting material. The results are compared with those found for the Pb(OAc)4 decarboxylation of the norbornane-, bornane-, and 2,3,3-trimethylnorbornane-2-carboxylic acids. The formation of the products is interpreted in terms of competitive cationic and SNi substitution.

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Structural Homogeneity in Unsaturated Fatty Acids of Marine Lipids. A Review

Journal of the Fisheries Research Board of Canada ◽

10.1139/f64-021 ◽

1964 ◽

Vol 21 (2) ◽

pp. 247-254 ◽

Cited By ~ 45

Author(s):

R. G. Ackman

Keyword(s):

Fatty Acids ◽

Double Bond ◽

Polyunsaturated Fatty Acids ◽

Chain Length ◽

Unsaturated Fatty Acids ◽

Analytical Data ◽

Double Bonds ◽

Marine Origin ◽

Methyl Group ◽

Marine Lipids

Consideration of recent analytical data supports the conclusion that the longer-chain polyunsaturated fatty acids of marine origin are all structurally homogeneous in that the double bonds are cis, the double bonds methylene interrupted, and that, with the exception of the C16 chain length, the ultimate double bond will normally be three, six or nine carbon atoms removed from the terminal methyl group.

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The Structure of Polyisoprenes. II. The Structure of β-Gutta-Percha

Rubber Chemistry and Technology ◽

10.5254/1.3546727 ◽

1945 ◽

Vol 18 (2) ◽

pp. 280-283

Author(s):

G. A. Jeffrey

Keyword(s):

Molecular Structure ◽

Double Bond ◽

Diffraction Data ◽

X Ray Diffraction ◽

Interatomic Distances ◽

Methyl Group ◽

X Ray ◽

Gutta Percha ◽

Qualitative Estimate

Abstract The x-ray diffraction data at present available from β-gutta-percha are shown to be insufficient to distinguish fine details of molecular structure. Since a qualitative estimate of the intensities on the fibre diagram can be adequately satisfied by a model having normal interatomic distances and valency angles, no evidence exists for the improbable distortion of the methyl group out of the plane of the double bond previously ascribed to the molecule.

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I. On a new class of bodies homologous to hydrocyanic acid. -I

Proceedings of the Royal Society of London ◽

10.1098/rspl.1867.0024 ◽

1868 ◽

Vol 16 ◽

pp. 144-147

Keyword(s):

Acetic Acid ◽

Formic Acid ◽

Hydrocyanic Acid ◽

Methyl Group ◽

New Class ◽

Atom Group ◽

The Difference

The typical transformation which hydrocyanic acid undergoes when submitted, under appropriate circumstances, to the action of water, is capable of assuming two different forms when accomplished in its homologues. If the hydrocyanic molecule be found to fix the elements of two molecules of water, yielding ultimately formic acid and ammonia, it is obvious that the atom group which in the homologues of hydrocyanic acid we assume in the place of hydrogen may be eliminated when these homologues are decomposed by water in conjunction either with formic acid or with ammonia. To take an example: —When acting with water upon the simplest homologue of hydrocyanic acid (upon cyanide of methyl), we may expect to see the methyl-group separating either in the form of methyl-formic, i. e . acetic acid, or in the form of methyl-ammonia, i. e . of methylamine, The difference of the two reactions and their relation to the metamorphosis of hydrocyanic acid itself are exhibited by the following equations:

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Studies in Vilsmeier-Haack reaction: Reaction of 3-methyl-1-phenyl-4-arylidene-5-pyrazolone

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19890706 ◽

1989 ◽

Vol 54 (3) ◽

pp. 706-712 ◽

Cited By ~ 10

Author(s):

Ibrahim M. A. Awad ◽

Khairy M. Hassan

Keyword(s):

Double Bond ◽

Vilsmeier Reaction ◽

Methyl Group ◽

Vilsmeier Reagent ◽

Carbon Double Bond ◽

Pyrazolone Derivatives

The 3-methyl group in Ia, b has been found to undergo diformylation by Vilsmeier reagent to give the aminoacrolein derivatives (IIa, b). Treatment of IIa, b with different reagents affords the related 1-phenyl-4-arylidene-5-pyrazolone derivatives with different heterocyclic systems in the 3-position. The Vilsmeier reaction on pyrazolopyrazole (XIII) have been utilized to prove chemically that new heterocyclic systems are formed only at the 3-position and no addition on the carbon-carbon double bond in the conjugated system O=C-C=C-(B) takes place.

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Effects of Several Androgens and Steroid Metabolites on Erythropoietin Production in the Isolated Perfused Dog Kidney

Blood ◽

10.1182/blood.v43.1.39.39 ◽

1974 ◽

Vol 43 (1) ◽

pp. 39-47 ◽

Cited By ~ 24

Author(s):

Luiz G. Paulo ◽

Gregory D. Fink ◽

Byung L. Roh ◽

James W. Fisher

Keyword(s):

Double Bond ◽

Spatial Configuration ◽

Significant Elevation ◽

Methyl Group ◽

Erythropoietin Production ◽

Dog Kidney ◽

Isolated Kidneys

Abstract In an attempt to clarify the role of the kidney in the action of several androgens and steroid metabolites on erythropoietin (ESF) production, ESF titers were measured in perfusates of isolated kidneys from dogs previously exposed to 4-hr hypoxia and perfused with blood containing testosterone (Test), 5α-17β-hydroxyandrostan-3-one (5αDHT), 5β-17β-hydroxyandrostan-3-one (5βDHT), 19-nortestosterone (19-nor), oxymetholone (Oxy), fluoxymesterone (Fluoxy), 3α-hydroxy-5β-pregnane, 11,20-dione (3αOH5βpreg), or 3β-hydroxy-5β-pregnane-20-one (3βOH-5 preg). ESF levels in the perfusates were assayed in exhypoxic polycythemic mice. Test, 5αDHT, oxy, fluoxy, and 3βOH5β-preg were found to produce a significant increase in ESF levels in the kidney perfusates. 5βDHT, 19-nor, and 3αOH5βpreg failed to produce a significant elevation in erythropoietin titers in the perfusates of the isolated perfused kidneys. These data suggest that the 4-5 double bond and the spatial configuration of the hydrogen at the 5 position as well as the lack of a methyl group in the 19 position of the basic androstan nucleus are important in the ability of these steroids to stimulate kidney production of ESF.

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BEZIEHUNGEN ZWISCHEN SUBSTITUTION IM RING A UND ABBAU IM STOFFWECHSEL BEI VERWANDTEN DES TESTOSTERONS

Acta Endocrinologica ◽

10.1530/acta.0.0410494 ◽

1962 ◽

Vol 41 (4) ◽

pp. 494-506 ◽

Cited By ~ 2

Author(s):

H. Langecker

Keyword(s):

Double Bond ◽

Ring System ◽

Keto Group ◽

Hydroxyl Group ◽

Methyl Group ◽

Structural Peculiarities ◽

Metabolic Degradation ◽

The Difference ◽

Testosterone Metabolites ◽

Derivatives Of

ABSTRACT Judging from the metabolites found in the urine, 1-methyl-androst-1-en-17β-ol-3-one (methenolone) and testosterone are metabolized in a different manner. For further clarification, other derivatives of testosterone with modifications in Ring A were investigated with regard to the oxidation of the 17-hydroxyl group. The production of urinary 17-ketosteroids decreased in the following sequence: testosterone; 1α-methyltestosterone and androstan-17β-ol-3-one; 1β-methyl-androstan-17β-ol-3-one; 2α-methyl-androstan-17β-ol-3-one and androst-1-en-17β-ol-3-one; 1α-methyl-androstan-17β-ol-3-one; 1-methyl-androsta-1,4-dien-17β-ol-3-one; 1,17α-dimethyl-androst-1-en-17β-ol-3-one and 1 -methyl-androst-1 -en-17β-ol-3-one (methenolone). The difference in metabolic degradation is also demonstrated in the fractionation of the urinary ketones. While after the administration of testosterone practically only hydrogenated 17-ketones are observed in the urine, the unchanged compound is still traceable in remarkable quantities after the administration of methenolone, along with minor quantities of the corresponding diketone. Testosterone-metabolites here are absent, whereas they represent the major substances present after the administration of androst-1-en-17β-ol-3-on. Following the administration of 1α-methyltestosterone only hydrogenated 17-ketones are detected which are still partly methylated. The 1-methyl-group and the Δ 1-double-bond seem to be responsible for the inhibition of the oxidation of methenolone in the 17-position. In addition, the hydrogenation of the double-bond and the reduction of the 3-keto-group are inhibited, obviously on account of the same structural peculiarities. The demethylation of methenolone is also inhibited. Any change in the steroid ring system forms a new substrate, thus producing new conditions for the enzymatic attack in the metabolic degradation.

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