Beta-unsaturated Ketones Research Articles

6-endo-trig mode cyclization to a hydrindanone using samarium (II) iodide

Samarium (II) iodide has been employed to promote the vinylogous pinacol coupling reaction of aldehyde to alpha, beta-unsaturated ketones. The diastereoselectivity of 6-endo-trig mode products was changed by the addition of a proton source and/or HMPA and by the reaction temperature. The stereochemistry of the hydrindanone was controlled by the coordinated samarium species, resulting in the cis-orientation in respect of the hydroxyl group at C-4 and the juncture proton at C-3a under mild reaction conditions. Coronafacic acid has been synthesized from a hydrindanone prepared by the cyclization reaction of the enone-aldehyde with samarium (II) iodide.

Mechanistic and synthetic aspects of the reaction of gamma-halogeno-alpha,beta-unsaturated ketones and esters with simple trialkyl phosphites.

Phosphorylation of different gamma-halogeno-alpha,beta-unsaturated ketones, ketoesters and diesters 11a-h with simple trialkyl phosphites gives 1,3-dienylphosphates 14, cyclopropylphosphonates 15, ketovinylphosphonates 17 and other products depending on the nature and number of activating groups and halogen atoms in the substrate. Most likely the reaction proceeds via oxaphospholene 23 which is in equilibrium with pseudorotamer 24 and an open, dipolar form 22. Dipolar form 33 is a likely intermediate when two activating groups are present.

Synthesis of substituted quinolines using the dianion addition of N-Boc-anilines and alpha-tolylsulfonyl-alpha,beta-unsaturated ketones.

A short and versatile synthesis of substituted quinolines is provided. Alkylation of sodium tolylsulfinate with bromomethyl- or chloromethyl ketones generates beta-keto sulfones. Knoevenagel condensation of the beta-keto sulfones with an aldehyde provides alpha-tolylsulfonyl-alpha,beta-unsaturated ketones. Michael addition of the dianion of N-Boc-anilines in the presence of CuCN and LiCl with the unsaturated ketone generates a 1,4-adduct, which after deprotection of the Boc group and thermal elimination of the tolyl sulfone provides the quinoline.

First anionic silyl migration from sp2 carbon to carbonyl oxygen. Stereospecific allylation of (Z)-beta-trimethylsilyl-alpha,beta-unsaturated ketones.

1,4-Silyl migration from sp2 carbon to carbonyl oxygen proceeded by the treatment of (Z)-beta-trimethylsilyl-alpha,beta-unsaturated ketones with copper(I) tert-alkoxide to afford vinylmetal species, which reacted with allylic halides to produce enol trimethylsilyl ethers of beta-alk-2-enyl-alpha,beta-unsaturated ketones with complete retention of configuration.

Regioselective synthesis of polysubstituted pyrazoles and isoxazoles.

A regioselective synthesis has been developed for the preparation of unsymmetrical 1,3,5-triaryl-4-alkylpyrazolines and -pyrazoles by treatment of alpha-benzotriazolyl-alpha,beta-unsaturated ketones with monosubstituted hydrazines followed by alkylation at the 4-position of the pyrazoline ring. Reaction of alpha-benzotriazolyl-alpha,beta-unsaturated ketones with hydroxylamine gives 3,5-disubstituted isoxazoles regioselectively.

Symmetric building blocks and combinatorial functional group transformation as versatile strategies in combinatorial chemistry.

A combination of symmetric building blocks and combinatorial functional group transformation for synthesis of pyrimidines was investigated. The purpose of the study was to maximize the return on invested synthetic efforts of reaction development for libraries. A representative set of symmetric diacids was coupled onto deprotected TentaGel Rink Amide resin. The amino function served as a model of a chemical process providing a functional group for additional synthetic steps, while the symmetric building blocks served as a model to connect synthesis protocols and to switch to a different synthesis paradigm consecutively. The reaction sequence was continued in a noncombinatorial step by coupling a bifunctional reagent (3-aminoacetophenone) to the remaining carboxy function of the symmetric diacid. The ketone served as a model of a reagent prepared for combinatorial functional group transformation. The arylmethylketone was reacted with a set of aryl- and heteroarylaldehydes to give alpha,beta-unsaturated ketones. Subsequently, guanidine, alkyl-, and arylcarboxamidines were introduced in combinatorial synthesis of substituted pyrimidines by reaction with the alpha, beta-unsaturated ketone functionality. The combination of symmetric building blocks and combinatorial functional group transformation created a versatile reaction sequence ideally suited for production of libraries from libraries with added diversity.

A formal total synthesis of (-)-cephalotaxine.

A formal total synthesis of (-)-cephalotaxine (1) has been achieved. The key step is an intramolecular aldol condensation of the diketone 9, which in turn was obtained in three steps from the azabicyclic compound 6 derived from D-proline according to Seebach's procedure. Treatment of 9 with a catalytic amount of sodium 2-methyl-2-butanolate in benzene at room temperature gave the alpha, beta-unsaturated ketone 8 in 43% yield. Catalytic hydrogenation of 8 followed by reduction of the ketone 22 with sodium borohydride and acetylation of the resulting alcohol 23 gave the acetoxy derivative 24, which, after deprotection, was acylated with (methylthio)acetic acid to give the amide 26. Compound 26 was converted into optically active ketolactam 4 following the synthetic operations developed for the synthesis of the racemic compound.

The ultra high pressure conjugate addition of indoles to electron-deficient olefins

The addition of indole and methyl indole at both high and ambient pressures to a series of Michael acceptors under the influence of ytterbium triflate was investigated. Under ambient pressure the more reactive and less sterically hindered electrophiles gave the expected 3-alkylated indoles in good to excellent yields. The more problematic Michael acceptors were subjected to pressures of 13 kbar. In all cases a dramatic reduction in reaction time and a significant improvement in yields was observed. In the cases involving 3-methylcyclohex-2-en-1-one, a by-product was formed and was characterized by single crystal X-ray diffraction. alpha , beta-Unsaturated ketones gave the best yields. Enals tended to polymerize while enoates proved to be much too unreactive. A particularly reactive malonate derived ester and beta-nitrostyrene gave good yields at ambient pressures.Key words: hapalindole, indole, Michael addition, high pressure, ytterbium triflate, Lewis acid.

Synthesis and immunotropic activity of some 2-aminobenzimidazoles, Part 4.

2-Aminobenzimidazole reacted with selected esters of alpha, beta-unsaturated acids and alpha, beta-unsaturated ketones to form derivatives of 1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-2-ones, 1,4-dihydropyrimido[1,2-a]benzimidazoles, and 2-acetylaminobenzimidazole. 2-Cinnamoylaminobenzimidazole, 4-phenyl-1,2,3,4-tetrahydropyrimido[1,2,-a]benzimidazol-2-on e, 4-(benzimidazol-2-ylamino)-4-phenylbutan-2-one, and 4-methyl-2-phenyl-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole were tested for their potential activity in immunological assays in the mouse model. Compound 1, at a dose of 100 micrograms/mouse, significantly inhibited the humoral immune response and, at the same time, stimulated the cellular type of that response. The proliferative response of mouse splenocytes to concanavalin A was inhibited only at a higher dose (2 micrograms/ml). The immunotropic activity of 4, on the other hand, was uniformly strongly inhibitory in all applied tests. The suppressive activity of 4 was lower in the cellular immune response and proliferation tests than that of cyclosporin A.

Mechanism of linoleic acid hydroperoxide reaction with alkali.

Treatment of (13S,9Z,11E)-13-hydroperoxy-9,11-octadecadienoic acid (13S-HPODE) with strong alkali resulted in the formation of about 75% of the corresponding hydroxy acid, (13S,9Z,11E)-13-hydroxy-9,11-octadecadienoic acid (13S-HODE), and the remaining 25% of products was a mixture of several oxidized fatty acids, the majority of which was formed from (9Z,11R,S,12S,R)-13-oxo-11,12-epoxy-9-octadecenoic acid by Favorskii rearrangement (Gardner, H.W., et al. (1993) Lipids 28, 487-495). In the present work, isotope experiments were completed in order to get further information about the initial steps of the alkali-promoted decomposition of 13S-HPODE. 1. Reaction of [hydroperoxy-18O2] 13S-HPODE with 5 M KOH resulted in the formation of [hydroxy-18O] 13S-HODE and [epoxy-18O](9Z,11R,S,12S,R)-13-oxo-11,12-epoxy-9-octadecenoi c acid; 2. treatment of a mixture of [U-14C] 13S-HODE and [hydroperoxy-18O2] 13S-HPODE with KOH and analysis of the reaction product by radio-TLC showed that 13S-HODE was stable under the reaction conditions and did not serve as precursor of other products; 3. reaction of a mixture of [U-14C] 13-oxo-9,11-octadecadienoic acid (13-OODE) and [hydroperoxy-18O2] 13S-HPODE with KOH resulted in the formation of [U-14C-epoxy-18O]99Z,11R,S,12S,R)-13-oxo-11,12-epoxy-9-octad ecenoic acid; 4. treatment of a mixture of [hydroperoxy-18O2] 13S-HPODE and [carboxyl-18O1] 13S-HPODE with KOH afforded (9Z,11R,S,12S,R)-13-oxo-11,12-epoxy-9-octadecenoic acid having an 18O-labeling pattern which was in agreement with its formation by intermolecular epoxidation. It was concluded that (9Z,11R,S,12S,R)-13-oxo-11,12-epoxy-9-octadecenoic acid is formed from 13S-HPODE by a sequence involving initial dehydration into the alpha, beta-unsaturated ketone, 13-OODE, followed by epoxidation of the delta 11 double bond of this compound by the peroxyl anion of a second molecule of 13S-HPODE. Rapid conversion of hydroperoxides by alkali appeared to require the presence of an alpha, beta-unsaturated ketone intermediate as an oxygen acceptor. This was supported by experiments with a saturated hydroperoxide, methyl 12-hydroperoxyoctadecanoate, which was found to be much more resistant to alkali-promoted conversion than 13S-HPODE.

Phosphorus-Containing Dendrimers. Easy Access to New Multi-Difunctionalized Macromolecules.

Phosphorus-containing dendrimers 1-[G'(1)]-1-[G'(4)] (generation 1 to generation 4) possessing terminal aldehyde groups reacted with a variety of hydrazino compounds. Addition of hydrazine itself to 1-[G'(1)]-1-[G'(4)] afforded the corresponding dendrimers 2-[G(1)]-2-[G(4)] with hydrazono groups at the periphery. Addition of methylhydrazine to 1-[G'(1)], 1-[G'(4)] gave the dendrimers 3-[G(1)], 3-[G(4)]. A Schiff reaction between 1-[G'(1)]-1-[G'(4)] and 1-amino-4-(2-hydroxyethyl)piperazine led to dendrimers 5-[G(1)]-5-[G(4)] possessing up to 48 alcohol chain ends. Treatment of 1-[G'(1)], 1-[G'(3)] with fluorenone hydrazone gave rise to macromolecules 7-[G(1)], 7-[G(3)] while the reaction of 1-[G'(1)], 1-[G'(2)], 1-[G'(4)] with 4-aminobenzo-15-crown-5 afforded the macromolecules 9-[G(1)], 9-[G(2)], 9-[G(4)] in which up to 48 crown ether units are anchored on the surface. Wittig reactions between 1-[G'(1)]-1-[G'(4)] with (acetylmethylene)triphenylphosphorane (10) or (cyanomethylene)triphenylphosphorane (12) allowed the formation of dendrimers 11-[G(1)]-11-[G(4)] or 13-[G(1)], 13-[G(4)] with alpha,beta unsaturated ketones or cinnamonitrile units, respectively, on the surface. Disubstitution of terminal P(S)Cl(2) groups of dendrimers 1-[G(1)]-1-[G(7)] with allylamine, propargylamine, or N-(trimethylsilyl)imidazole easily occurred to give macromolecules 14-[G(1)]-14-[G(7)], 15-[G(1)], 15-[G(4)], 16-[G(1)], 16-[G(4)].

New method for assaying free and total cholesterol in cultured cells by high-pressure liquid chromatography.

We developed a simple, sensitive and accurate method for assaying cellular free and total cholesterol by monitoring 4-cholesten-3-one, a conversion product of the cholesterol oxidase-catalyzed oxidation of the free cholesterol that has a strong chromophoric alpha, beta-unsaturated ketone at 240 nm, using a high-pressure liquid chromatographic system. This method measured picomole quantities of free and total cholesterol and precisely determined their concentrations in cells (10(4) range) in culture using 7 beta-hydroxycholesterol as an internal standard.

Disposition of CS-670, a novel nonsteroidal anit-inflammatory drug, and its metabolites in healthy human volunteers.

CS-670, a novel nonsteroidal anti-inflammatory drug, is a racemic prodrug. Plasma concentrations and urinary excretion of CS-670 and its metabolites were determined in experimental subjects after oral administration at a single 120 mg dose. CS-670 and four metabolites, the saturated ketone (M-A), unsaturated-alcohol (M-B), cis-alcohol (M-C), and trans-alcohol (M-D), were quantitated by GC-MS. The major metabolites in human plasma were M-B, M-C, and M-D and their terminal half-lives (t1/2) were 0.9, 2.6, and 1.2 h, respectively. The total recovery in the urine was 26% of the dose, but unchanged CS-670 accounted for less than 2% over a 48 h period. In addition, the absolute configurations of the metabolites were examined by HPLC after derivatization with chiral reagents. It was found that the configuration of the propionic acid moiety of the metabolites, M-B, M-C, and M-D, in human plasma, was rapidly inverted from (-)-(R) to the (+)-(S) configuration in stereoselective biotransformation. Furthermore, the configurations of the 1'- and 2'-carbons of M-C and M-D, were found to be (1'R, 2'S) and (1'R, 2'S), respectively. These results show that CS-670 is readily biotransformed by chiral inversion of the 2-arylpropionic acid moiety and stereoselective reduction of the alpha, beta-unsaturated ketone moiety in humans.

Cell cycle arrest by prostaglandin A1 at the G1/S phase interface with up‐regulation of oncogenes in S‐49 cyc− cells

Our previous studies have implied that prostaglandins inhibit cell growth independent of cAMP. Recent reports, however, have suggested that prostaglandin arrest of the cell cycle may be mediated through protein kinase A. In this report, in order to eliminate the role of c-AMP in prostaglandin mediated cell cycle arrest, we use the -49 lymphoma variant (cyc-) cells that lack adenylate cyclase activity. We demonstrate that dimethyl prostaglandin A1 (dmPGA1) inhibits DNA synthesis and cell growth in cyc- cells. DNA synthesis is inhibited 42% by dmPGA1 (50 microM) despite the fact that this cell line lacks cellular components needed for cAMP generation. The ability to decrease DNA synthesis depends upon the specific prostaglandin structure with the most effective form possessing the alpha, beta unsaturated ketone ring. Dimethyl PGA1 is most effective in inhibiting DNA synthesis in cyc- cells, with prostaglandins PGE1 and PGB1 being less potent inhibitors of DNA synthesis. DmPGE2 caused a significant stimulation of DNA synthesis. S-49 cyc- variant cells exposed to (30-50 microns) dmPGA1, arrested in the G1 phase of the cell cycle within 24 h. This growth arrest was reversed when the prostaglandin was removed from the cultured cells; growth resumed within hours showing that this treatment is not toxic. The S-49 cyc- cells were chosen not only for their lack of adenylate cyclase activity, but also because their cell cycle has been extensively studied and time requirements for G1, S, G2, and M phases are known. Within hours after prostaglandin removal the cells resume active DNA synthesis, and cell number doubles within 15 h suggesting rapid entry into S-phase DNA synthesis from the G1 cell cycle block.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a terpenoid, (—)-6-Hydroxy-4-(1-hydroxy-1-methylethyl)-1-cyclohexene-1-ethanol, on drug-metabolizing enzymes and glutathione content in rat liver and lung

1. Chronic treatment of Sprague-Dawley rats with the new terpenoid mucoregulating drug (I) did not modify activities of the drug-metabolizing enzymes (phase I and phase II) of liver and lung. 2. Acute treatment of rats with I did not affect the GSH content of liver and lung, but administration of the corresponding alpha, beta-unsaturated ketone (II) produced considerable GSH depletion in both tissues, the original GSH levels being restored after a few hours. 3. The results are discussed in comparison with those previously obtained with the structurally related drug trans-sobrerol (III).

Identification and characterization of deoxyguanosine adducts of methyl vinyl ketone and ethyl vinyl ketone. Genotoxicity of the ketones in the SOS chromotest

The reaction of the alpha, beta-unsaturated ketones methyl vinyl ketone (MVK) and ethyl vinyl ketone (EVK) with nucleosides and 5'-mononucleotides was studied. The genotoxic activity of MVK and EVK in the SOS Chromotest was investigated. Three different types of adducts with deoxyguanosine were found and their structures elucidated: the cyclic 1,N2 adducts, the linear N7 adducts with one still-unreacted carbonyl function, and the cyclic 1,N2, linear N7, bis adducts. The spectroscopic and other relevant characterization data for the deoxyguanosine adducts and the corresponding guanine adducts are presented here together with details of the chromatographic methods used for isolation. The adducts described could also be isolated in the reactions of MVK and EVK with 2'-deoxyguanosine 5'-monophosphate. No adducts could be isolated either with nucleosides other than deoxyguanosine or with nucleotides other than 2'-deoxyguanosine 5'-monophosphate, indicating that the guanine moiety is the most reactive DNA constituent for MVK and EVK. MVK and EVK were clearly genotoxic in the SOS Chromotest according to the criteria of Quillardet and Hofnung. The formation of these adducts was proposed as the mechanism for the genotoxicity of MVK and EVK: all data available support the assumption that MVK and EVK represent a mutagenic and carcinogenic risk for mankind.

On the mechanism of toxicity of illudins: the role of glutathione

Illudin M and illudin S, antitumor sesquiterpenes from Omphalotus illudens, have been found to react with thiols in a pH-dependent manner. The optimum pH values for reaction of illudin M with methyl thioglycolate, cysteine, and glutathione were 5.8, 5.6, and 6.1, respectively, and pseudo-first-order rate constants at 25 degrees C (10-fold excess of thiol) were 44 x 10(-3), 11.5 x 10(-3), and 11.3 x 10(-3) min-1. In all cases, thiol added to the alpha, beta-unsaturated ketone giving an unstable intermediate. Subsequent loss of the tertiary hydroxyl and opening of the cyclopropane ring afforded a stable aromatic product. The toxicity of illudin S to HL60 cells was increased by lowering glutathione levels in the cells and vice versa. General toxicity and antitumor activity of illudins are discussed in the light of these results.

Photooxidation products of smoke generator fuel (SGF) no. 2 fog oil and toxicity toHyallela azteca

Photooxidation of smoke generator fuel (SGF) No. 2 fog oil was investigated to determine qualitative changes in the chemistry of the oil and the resulting acute toxicity to the freshwater amphipod Hyallela azteca. The 48-h LC50 was about 11.5 mg total oil/L for photooxidized fog oil. Toxicity was related to the greater solubility of photooxidized fog oil in that higher concentrations of total dissolved oil in oil-water mixtures were obtained after equivalent additions of photooxidized oil and nonphotooxidized oil. Photooxidation caused increases in carbonyl oxygen and the presence of alpha- and beta-unsaturated ketones and acetophenones in aqueous extracts. There was no evidence for the formation of phenolic compounds in the photooxidized fog oil or in oil-water mixtures.

Silyl Derivatives in the Synthesis of trans-beta-Trimethylsilyl-alpha,beta-unsaturated Ketones.

Silyl Derivatives in the Synthesis of trans-beta-Trimethylsilyl-alpha,beta-unsaturated Ketones.

Biotransformation of trans-sobrerol. III. Metabolites of 8-hydroxycarvotanacetone in the rat.

The metabolism of 8-hydroxycarvotanacetone (HCA), a major metabolite of trans-sobrerol, was studied in female rats after a single oral dose. The metabolic pathways include hydroxylation, reduction to cis- and trans-sobrerol, glucuronylation and Michael addition with glutathione giving rise to mercapturic acids which then undergo reduction. Biological reduction appears to occur more readily for the alicyclic-saturated ketones (Michael adducts) than for the alpha, beta unsaturated ketones (HCA and hydroxylated metabolites). This is in agreement with the chemical reactivity of the compounds.