- Phenolic compounds from Peperomia obtusifolia
-
From the aerial parts of Pepermia obtusifolia, five phenolic compounds bearing a methyl, an isoprenyl and a geranyl group on a benzene ring core have been isolated. The structures were determined by the spectroscopic analysis including 2D NMR techniques and synthesis.
- Tanaka, Toshiyuki,Asai, Fujio,Iinuma, Munekazu
-
-
Read Online
- Structure-activity relationship study of antitrypanosomal chalcone derivatives using multivariate analysis
-
Chagas disease represents one of several neglected diseases with a reduced number of chemotherapeutical drugs including the highly toxic compounds benznidazole and nifurtimox. In this sense, natural products represent an import scaffold for the discovery of new biologically active compounds, in which chalcones are promising representatives due to their antitrypanosomal potential. In this work, a series of 36 chalcone derivatives were synthesized and tested against trypomastigotes of Trypanosoma cruzi. In addition, a detailed investigation on their molecular features was performed. The obtained results suggest that certain molecular features are fundamental for an efficient antitrypanosomal potential of chalcones, such as allylic groups, α,β-unsaturated carbonyl system, and aromatic hydroxyl groups. These results were obtained based on the interpretation of machine-learning and multivariate statistical methods, which revealed the essential characteristics of chalcone prototypes against trypomastigotes of T. cruzi.
- Gomes, Kaio S.,da Costa-Silva, Thais A.,Oliveira, Igor H.,Aguilar, Andrea M.,Oliveira-Silva, Diogo,Uemi, Miriam,Silva, Wender A.,Melo, Lennine R.,Andrade, Carlos Kleber Z.,Tempone, Andre G.,Baldim, Jo?o L.,Lago, Jo?o Henrique G.
-
-
Read Online
- Solid-phase synthesis of β-mono-substituted ketones and an application to the synthesis of a library of phlorizin derivatives
-
We describe a novel reaction sequence for the solid-phase synthesis of β-mono-substituted ketones. The methodology involves an aldol condensation reaction, followed by reduction of the resultant double bond and allows the introduction of a range of alkyl chains to solid-linked ketones at α position. Using the methodology we accomplished the synthesis of phlorizin library of 132 compounds using 43 aldehydes and four glycosyl bromides.
- Tanaka, Hiroshi,Zenkoh, Tatsuya,Setoi, Hiroyuki,Takahashi, Takashi
-
-
Read Online
- Synthesis and biological activity of (±)-7,3′,4′-trihydroxyhomoisoflavan and its analogs
-
Acetylcholinesterase (AChE) inhibitors and neurite outgrowth promoters are thought to alleviate the symptoms of degenerative brain disorders, such as Alzheimer's disease. We designed and synthesized a series of homoisoflavonoids based on the structure of natural homoisoflavan isolated from Dracaena cambodiana dragon's blood. The homoisoflavonoids were then evaluated as AChE inhibitors and neurite outgrowth promoters. The catechol structure of the homoisoflavan B rings was important for AChE inhibition, and some of the homoisoflavonoids significantly promoted neurite outgrowth induced by nerve growth factor (NGF).
- Noshita, Toshiro,Fujita, Kentaro,Koga, Takeru,Ouchi, Hidekazu,Tai, Akihiro
-
-
- Stereoselective reduction of flavanones by marine-derived fungi
-
Biotransformation is an alternative with great potential to modify the structures of natural and synthetic flavonoids. Therefore, the bioreduction of synthetic halogenated flavanones employing marine-derived fungi was described, aiming the synthesis of flavan-4-ols 3a-g with high enantiomeric excesses (ee) of both cis- and trans-diastereoisomers (up to >99% ee). Ten strains were screened for reduction of flavanone 2a in liquid medium and in phosphate buffer solution. The most selective strains Cladosporium sp. CBMAI 1237 and Acremonium sp. CBMAI1676 were employed for reduction of flavanones 2a-g. The fungus Cladosporium sp. CBMAI 1237 presented yields of 72–87% with 0–64% ee cis and 0–30% ee trans with diastereoisomeric ratio (dr) from 52:48 to 64:36 (cis:trans). Whereas Acremonium sp. CBMAI 1676 resulted in 31% yield with 77–99% ee of the cis and 95–99% ee of the trans-diastereoisomers 3a-g with a dr from 54:46 to 96:4 (cis:trans). To our knowledge, this is the first report of the brominated flavon-4-ols 3e and 3f. The use of fungi, with emphasis for these marine-derived strains, is an interesting approach for enantioselective reduction of halogenated flavanones. Therefore, this strategy can be explored to obtain enantioenriched compounds with biological activities.
- Birolli, Willian G.,Nitschke, Marcia,Porto, André Luiz M.,Santos, Darlisson de A.,de Matos, Iara L.
-
-
- B regioselective and chemoselective biotransformation of 2′-hydroxychalcone derivatives by marine-derived fungi
-
Eight fungal strains (Penicillium raistrickii CBMAI 931, Cladosporium sp. CBMAI 1237, Aspergillus sydowii CBMAI 935, Penicillium oxalicum CBMAI 1996, Penicillium citrinum CBMAI 1186, Mucor racemosus CBMAI 847, Westerdykella sp. CBMAI 1679, and Aspergillus sclerotiorum CBMAI 849) mediated the biotransformation of the 2′-hydroxychalcone 1a. The main products obtained were from hydrogenation, hydroxylation, and cyclization reactions. Penicillium raistrickii CBMAI 931 catalyzed the chemoselective reduction of 1a to produce 2′-hydroxydihydrochalcone 2a (72%) in 7 days of incubation in phosphate buffer (pH 7). Aspergillus sydowii CBMAI 935 promoted the hydroxylation of 1a to yield 2′,4-dihydroxy-dihydrochalcone 5a (c = 42%) in 7 days of incubation in phosphate buffer (pH 8). The reaction using P. citrinum CBMAI 1186 and M. racemosus CBMAI 847 presented main cyclization products in phosphate buffer (pH 8), but the reactions with these fungi did not present enantioselectivity. Marine-derived fungi were effective and versatile biocatalysts for biotransformation of the 2′-hydroxychalcones yielding different products according to the conditions and microorganism used.
- Nitschke, Marcia,Porto, André Luiz Meleiro,de Matos, Iara Lisboa
-
-
- Transfer Hydrogenation of Flavanones and ortho-Hydroxychalcones to 1,3-Diarylpropanols Catalyzed by CNN Pincer Ruthenium Complexes
-
The transfer hydrogenation of flavanones and ortho-hydroxychalcones catalyzed by ruthenium pincer complexes RuCl(CNNPh)(disphosphine) has allowed the synthesis of ortho-hydroxy 1,3-diarypropanols in 80–88 % yield, under mild reaction conditions and short reaction times (1 h) in 2-propanol. The amount of the co-catalyst NaOiPr has been found crucial for the selective reduction of flavanones to ortho-hydroxy 1,3-diarypropanols vs. flavan-4-ols. Preliminary results show that with pincer catalysts bearing (S,R)-Josiphos, flavanone is reduced to the corresponding (S)-alcohol in moderate conversion (36 %) and up to 92 % ee.
- Soto, Martín,Gotor-Fernández, Vicente,Rodríguez-Solla, Humberto,Baratta, Walter
-
p. 2152 - 2157
(2021/03/03)
-
- Versatile formation of Ru(II) hydrazone complexes: Structure, theoretical studies and catalytic activity in α-alkylation
-
New 1-(anthracen-10-yl)methylene)-2-(benzo[d]thiazol-2-yl)hydrazine (BHA) and 1-(anthracen-10-yl)methylene)-2-(quinolin-2-yl)hydrazine (QHA) ligands were reacted with [RuHCl(CO)(E)3] (E = PPh3 or AsPh3) or [RuCl2(AsPh3)3] in a 1:1 mol ratio in chloroform-ethanol medium to synthesis new ruthenium complexes. All the new ruthenium complexes were analyzed by elemental analysis, IR, NMR (1H, 13C and 31P) spectroscopy, ESI-Mass spectrometry and single crystal XRD techniques. The single crystal XRD study reveals the octahedral geometry around the ruthenium ion. The study also shows that the ligands coordinate with the Ru metal as monoanionic bidentate N^N donors in complexes 1, 3 and 4 and as a neutral bidentate N^N donor in complex 2 by forming five or four member chelate rings. The intramolecular interactions in the crystal lattices were studied by Hirshfeld surface analysis. The results indicate that π-stacking contacts play an important role in the crystal lattices. DFT calculations were carried out to explain the solid structures of complexes 1–3. Moreover, the synthesized complexes were screened as catalysts for the α-alkylation of ketones with alcohols. The effect of various parameters, such as base, solvent, temperature, time, substituents and also catalyst loading, on the catalytic activity were analyzed. The results depict that the complex 3 was found to be an efficient catalyst for the synthesis of α-alkylation products.
- Kavitha, Venkatachalam,Murugan, Kaliyappan,Vijayapritha, Subbarayan,Viswanathamurthi, Periasamy
-
-
- Synthesis and structural characterization of facile ruthenium(II) hydrazone complexes: Efficient catalysts in α-alkylation of ketones with primary alcohols via hydrogen auto transfer
-
As a immersion for development of new complexes, new Ru(II) complexes (1–3) supported by benzothiazole hydrazine Schiff bases of the type [Ru(SAL-HBT)(CO)(AsPh3)2], [Ru(VAN-HBT)(CO)(AsPh3)2] and [Ru(NAP-HBT)(CO)Cl(AsPh3)2] [SAL-HBT = (salicyl((2-(benzothiazol-2yl)hydrazono)methylphenol)), VAN-HBT = 2-((2-(benzothiazol-2-yl)hydrazono)methyl)-6 methoxyphenol) and NAP-HBT = naphtyl-2-((2-(benzothiazol-2-yl)hydrazono)methyl phenol)] were synthesized. Their identities have been established by satisfactory elemental analyses, various spectroscopic techniques (IR, (1H, 13C) NMR) and also mass spectrometry. The ruthenium(II) ion exhibits a hexa coordination with distorted octahedral geometry. In complexes 1 and 2, the ligand coordinated as dianionic tridentate fashion by forming N^N donor five member and N^O donor six member chelate rings. However, in complex 3, the ligand coordinated as monoanionic bidentate fashion by forming N^N donor five-membered ring. The new ruthenium(II) carbonyl complexes were successfully applied as catalysts in α -alkylation of aliphatic and aromatic ketones with alcohols via borrowing hydrogen strategy. Various parameters such as base, solvent, temperature, time and catalyst loading on the catalytic activity were analyzed. From the results, the catalyst 1 was found to be the best catalyst for α-alkylation reaction to obtain excellent yield. The catalytic system has a broad substrate scope, which allows the synthesis of α-alkylated ketones in mild reaction conditions with low catalyst loading under air atmosphere.
- Kalaiarasi, Chinnasamy,Murugan, Kaliyappan,Vijayan, Paranthaman,Vijayapritha, Subbarayan,Viswanathamurthi, Periasamy
-
supporting information
(2020/08/06)
-
- Nickel-Catalyzed Directed Cross-Electrophile Coupling of Phenolic Esters with Alkyl Bromides
-
Herein, we demonstrate the successful use of robust phenolic esters as an electrophilic acyl source in the reaction with diverse primary and secondary unactivated alkyl bromides. The cleavage of the relatively inert C-O bond is facilitated by the neighboring coordinating hydroxyl or sulfonamide moiety. By circumventing the use of pregenerated organometallics, this method allows efficient preparation of a variety of o-hydroxyl and tosyl-protected o-amino aryl ketones with high compatibility with a wide range of functionalities.
- Ding, Decai,Wang, chuan,Yang, feiyan
-
supporting information
p. 9203 - 9209
(2020/12/22)
-
- Solvent-Controlled Hydrogenation of 2’-Hydroxychalcones: A Simple Solution to the Total Synthesis of Bussealins
-
A solvent-controlled hydrogenation of 2’-hydroxychalcones to selectively obtain different hydrogenation products is herein reported. Thus, hydrogenation of 2’-hydroxychalcones using EtOH as solvent provided the corresponding 1,3-diarylpropanes in excellent yields. On the contrary, when the hydrogenation was performed in DCM, the corresponding dihydrochalcones were isolated. Switching the reaction solvent to n-BuOH/H2O (1:1), afforded 1,3-diarylpropanols from moderate to good yields. The methodology here reported offers a straightforward, simple and cost-effective method for the preparation of a wide variety of 2’-hydroxy-1,3-diarylpropanes derivatives, and was also applied to the preparation of natural Bussealins C and D. (Figure presented.).
- Soto, Martín,Soengas, Raquel G.,Rodríguez-Solla, Humberto
-
p. 5422 - 5431
(2020/10/06)
-
- Chemoselective Hydrosilylation of the α,β-Site Double Bond in α,β- And α,β,γ,δ-Unsaturated Ketones Catalyzed by Macrosteric Borane Promoted by Hexafluoro-2-propanol
-
The B(C6F5)3-catalyzed chemoselective hydrosilylation of α,β- and α,β,γ,δ-unsaturated ketones into the corresponding non-symmetric ketones in mild reaction conditions is developed. Nearly 55 substrates including those bearing reducible functional groups such as alkynyl, alkenyl, cyano, and aromatic heterocycles are chemoselectively hydrosilylated in good to excellent yields. Isotope-labeling studies revealed that hexafluoro-2-propanol also served as a hydrogen source in the process.
- Zhan, Xiao-Yu,Zhang, Hua,Dong, Yu,Yang, Jian,He, Shuai,Shi, Zhi-Chuan,Tang, Lei,Wang, Ji-Yu
-
p. 6578 - 6592
(2020/07/17)
-
- I-Pr2NMgCl·LiCl Enables the Synthesis of Ketones by Direct Addition of Grignard Reagents to Carboxylate Anions
-
The direct preparation of ketones from carboxylate anions is greatly limited by the required use of organolithium reagents or activated acyl sources that need to be independently prepared. Herein, a specific magnesium amide additive is used to activate and control the addition of more tolerant Grignard reagents to carboxylate anions. This strategy enables the modular synthesis of ketones from CO2 and the preparation of isotopically labeled pharmaceutical building blocks in a single operation.
- Colas, Kilian,Dos Santos, A. Catarina V. D.,Mendoza, Abraham
-
supporting information
(2019/10/08)
-
- Water-mediated phosphorylative cyclodehydrogenation: An efficient preparation of flavones and flavanones
-
A new synthetic strategy utilizing POCl3-water for the conversion of 2′-hydroxychalcones to flavanones and flavones has been developed. The reagent efficiently promoted one-pot conversion of 2′-hydroxychalcones to flavones through flavanones involving cyclization and oxidative dehydrogenation. By changing the stoichiometery of the reagents, the reaction can be tuned to generate either flavanone or flavone. The developed protocol was found to be applicable for a variety of 2′-hydroxychalcones.
- Vimal, Manorama,Pathak, Uma,Halve, Anand Kumar
-
p. 2805 - 2814
(2019/08/12)
-
- Chemoselective transfer hydrogenation of Α,Β-unsaturated carbonyls catalyzed by a reusable supported Pd nanoparticles on biomass-derived carbon
-
We herein report highly chemoselective transfer hydrogenation of α,β-unsaturated carbonyl compounds to saturated carbonyls with formic acid as a hydrogen donor over a stable and recyclable heterogeneous Pd nanoparticles (NPs) on N,O-dual doped hierarchical porous biomass-derived carbon. The synergistic effect between Pd NPs and incorporated heteroatoms on carbon plays a critical role on promoting the reaction efficiency. A series of α,β-aromatic and aliphatic unsaturated carbonyl compounds was selectively reduced to their corresponding saturated carbonyls in up to 97% isolated yields with good tolerance of various functional groups. In addition, the catalyst can be successively reused for at least 6 times without significant loss in reaction efficiency.
- Song, Tao,Duan, Yanan,Yang, Yong
-
-
- Chemoselective Hydrogenation of α,β-Unsaturated Carbonyls Catalyzed by Biomass-Derived Cobalt Nanoparticles in Water
-
Herein, we report highly chemoselective hydrogenation of α,β-unsaturated carbonyls to saturated carbonyls catalyzed by cobalt nanoparticles supported on the biomass-derived carbon from bamboo shoots with molecular hydrogen in water, which is the first prototype using a heterogeneous non-noble metal catalyst for such organic transformation as far as we know. The optimal cobalt nanocatalyst, CoOx@NC-800, manifested remarkable activity and selectivity for hydrogenation of C=C in α,β-unsaturated carbonyls under mild conditions. A broad set of α,β-aromatic and aliphatic unsaturated carbonyls were selectively reduced to their corresponding saturated carbonyls in up to 99 % yields with good tolerance of various functional groups. Meanwhile, a new straightforward one-pot cascade synthesis of saturated carbonyls was realized with high activity and selectivity via the cross-aldol condensation of ketones with aldehydes followed by selective hydrogenation. More importantly, this one-pot strategy is applicable for the expedient synthesis of Loureirin A, a versatile bioactive and medicinal molecule, from readily available starting materials, further highlighting the practical utility of the catalyst. In addition, the catalyst can be easily separated for successive reuses without significant loss in both activity and selectivity.
- Song, Tao,Ma, Zhiming,Yang, Yong
-
p. 1313 - 1319
(2019/01/25)
-
- Methanol as hydrogen source: Chemoselective transfer hydrogenation of α,β-unsaturated ketones with a rhodacycle
-
Methanol is a safe, economic and easy-to-handle hydrogen source. It has rarely been used in transfer hydrogenation reactions, however. We herein report that a cyclometalated rhodium complex, rhodacycle, catalyzes highly chemoselective hydrogenation of α,β-unsaturated ketones with methanol as the hydrogen source. A wide variety of chalcones, styryl methyl ketones and vinyl methyl ketones, including sterically demanding ones, were reduced to the saturated ketones in refluxing methanol in a short reaction time, with no need for inter gas protection, and no reduction of the carbonyl moieties was observed. The catalysis described provides a practically easy and operationally safe method for the reduction of olefinic bonds in α,β-unsaturated ketone compounds.
- Aboo, Ahmed H.,Begum, Robina,Zhao, Liangliang,Farooqi, Zahoor H.,Xiao, Jianliang
-
p. 1795 - 1799
(2019/11/11)
-
- Iridium catalyzed alkylation of 2′-hydroxyacetophenone with alcohols under thermal or microwave conditions
-
2′-Hydroxyacetophenone was alkylated with a range of substituted benzyl and heteroaryl alcohols to afford the corresponding C-alkylated products in good yields under microwave irradiation. The C-alkylated products were reacted with bromoacetonitrile to afford 2-amino-3-benzyl 1,4-naphthoquinone derivatives in moderate yields.
- Hunter, Jamie,Rice, Scott,Lowe, Robert,Pask, Christopher M.,Warriner, Stuart,Sridharan, Visuvanathar
-
supporting information
p. 4400 - 4402
(2017/10/23)
-
- The insertion of arynes into the O-H bond of aliphatic carboxylic acids
-
The insertion of arynes into the O-H bond of aliphatic carboxylic acids promoted by sodium carboxylates is described. The reactions led to the formation of aryl carboxylates in good yields with good chemoselectivities under mild conditions.
- Wen, Chunxiao,Chen, Qian,He, Zhenwen,Yan, Xinxing,Zhang, Changyuan,Du, Zhiyun,Zhang, Kun
-
supporting information
p. 5470 - 5473
(2015/09/15)
-
- A Baker-Venkataraman retro-Claisen cascade delivers a novel alkyl migration process for the synthesis of amides
-
A simple extension of the carbamoyl Baker-Venkataraman rearrangement has been developed. If residual water in the reaction is not strictly excluded a Baker-Venkataraman retro-Claisen cascade takes place, giving amide products, in which an alkyl group apparently migrates between two functionalities of the substrate.
- Ameen, Dana,Snape, Timothy J.
-
supporting information
p. 1816 - 1819
(2015/03/30)
-
- Organic compounds
-
Disclosed are certain compounds according to the general formula (I) and their use as flavoring and fragrancing compounds, as well as fragranced and flavored compositions comprising the compounds of formula (I), and methods for providing a flavor or fragrance to compositions and articles utilizing the compounds of formula (I).
- -
-
Page/Page column
(2014/11/13)
-
- Replacing a stoichiometric silver oxidant with air: Ligated Pd(II)-catalysis to β-aryl carbonyl derivatives with improved chemoselectivity
-
Air was employed as a green reoxidant of Pd(0), replacing stoichiometric and toxic silver salt, in the chelation-controlled Pd(II)-modulated arylative enolization of prop-2-en-1-ols to acquire synthetically-important β-aryl carbonyl derivatives. This green approach, which didn't require acid or base, allowed the compatibility of a range of functionalities (inclusive of -I, -Br & -Cl), resulting in the construction of structurally-diverse dihydrochalcones, α-benzyl-α′-alkyl acetones, α-benzyl β-keto esters and dihydrocinnamaldehydes. In addition to organoboronic acids, efficient coupling was also achieved with boronic esters and trifluoroborate salts. A deuterium labelling experiment revealed an interesting 1,2-hydrogen shift after β-arylation in the catalytic process. the Partner Organisations 2014.
- Vellakkaran, Mari,Andappan, Murugaiah M.S.,Kommu, Nagaiah
-
supporting information
p. 2788 - 2797
(2014/05/06)
-
- Lithium tert-butoxide mediated α-alkylation of ketones with primary alcohols under transition-metal-free conditions
-
LiOtBu was found to efficiently promote the α-alkylation reaction of ketones with primary alcohols, without the addition of any transition metal catalyst.
- Liang, Yu-Feng,Zhou, Xin-Feng,Tang, Shi-Ya,Huang, Yao-Bing,Feng, Yi-Si,Xu, Hua-Jian
-
p. 7739 - 7742
(2013/06/27)
-
- Synthesis of chromones through LiOtBu/air-mediated oxidation and regioselective cyclization of o-hydroxyphenyl propargyl carbinols
-
A cascade oxidative cyclization reaction for the synthesis of chromone derivatives was developed by using LiOtBu as a mediator and air as an oxidant. The reaction was carried out without the assistance of a transition metal under mild conditions to afford the chromones in good yields with high regioselectivities. A tandem reaction for the synthesis of various chromones was developed. LiOtBu was used as a mediator and air was used as a clean oxidant. The reaction generally showed high regioselectivity under mild conditions. Extensive research showed that dehydrogenative oxidation of the alcohols under strongly basic conditions was the crucial step, and Li+ was also found to play an important role in this process. Copyright
- Zhang, Shuai,Wan, Changfeng,Wang, Qiang,Zhang, Baiqun,Gao, Lingfeng,Zha, Zhenggen,Wang, Zhiyong
-
p. 2080 - 2083
(2013/05/09)
-
- 3-Ylidenephthalides as a new class of transient receptor potential channel TRPA1 and TRPM8 modulators
-
Following the recent identification of the naturally occurring 3-ylidene-4,5-dihydrophthalide ligustilide and its oxidation product dehydroligustilide as novel TRPA1 modulators, a series of seventeen 3-ylidenephthalides was synthesized and tested on TRPA1 and TRPM8 channels. Most of these compounds acted as strong modulators of the two channel types with EC50 and/or IC50 values distinctly lower than those of the reference compounds.
- Ortar, Giorgio,Schiano Moriello, Aniello,Morera, Enrico,Nalli, Marianna,Di Marzo, Vincenzo,De Petrocellis, Luciano
-
p. 5614 - 5618
(2013/10/01)
-
- Microbial synthesis of dihydrochalcones using Rhodococcus and Gordonia species
-
Chalcones are important compounds in food and cosmetics industry, and in food chemistry research. We have developed a method of synthesis of dihydrochalcones from flavanone and α,β-unsaturated chalcones by microbial hydrogenation. It has been found that bacterial strains of Rhodococcus sp. and Gordonia sp. can be successfully used in the key step of dihydrochalcones synthesis. This kind of activity has not been previously examined. Twelve microorganisms were initially screened for their ability to catalyze biotransformation reactions of selected flavonoid compounds. Of these, Rhodococcus sp. and Gordonia sp. transformed flavanone and chalcones to hydrogenation products in good isolated yield of 13-94%.
- Stompor, Monika,Potaniec, Bartomiej,Szumny, Antoni,Zielinski, Pawe,Zonierczyk, Anna Katarzyna,Aniol, Miroslaw
-
p. 283 - 288
(2013/10/22)
-
- Microbial transformations of chalcones to produce food sweetener derivatives
-
Biotransformations of two substrates: chalcone (1) and 2′- hydroxychalcone (4) were carried out using four yeast strains and five filamentous fungi cultures. Substrate 1 was effectively hydrogenated in all of tested yeast cultures (80-99% of substrate conversion after 1 h of biotransformation) affording dihydrochalcone 2. In the cultures of filamentous fungi the reaction was much slower, however, Chaetomium sp. gave product 2 in 97% yield. After 12 h of incubation a reduction of dihydrochalcone 2 to alcohol 3 was additionally observed. After 3 days of biotransformation in the culture of Rhodotorula rubra product (S)-3 was obtained with 75% ee (enantiomeric excess) and 99% of conversion. Also after a 3-day biotransformation using the strain Fusarium culmorum product (R)-3 was obtained with 98% ee and 97% of conversion. In most of the tested strains a change in enantiomeric excess of compound 3 during the biotransformation process was noticed. In the culture of Rhodotorula glutinis after 3 h of transformation alcohol (R)-3 was formed with 47% ee and 31% of substrate conversion, whereas after 6 days the (S)-3 enantiomer was obtained with 99% ee and 91% of conversion. In the case of 2′- hydroxychalcone (4), the hydrogenation proceeded much slower and led to 2′-hydroxydihydrochalcone (5) - in the culture of Yarrowia lipolytica 97% of conversion was observed after 3 days. In all cultures of the tested strains no products of 2′-hydroxydihydrochalcone reduction were detected.
- Janeczko, Tomasz,Gladkowski, Witold,Kostrzewa-Suslow, Edyta
-
-
- Rhodium-phosphoramidite catalyzed alkene hydroacylation: Mechanism and octaketide natural product synthesis
-
We describe a method that allows salicylaldehyde derivatives to be coupled with a wide range of unactivated alkenes at catalyst loadings as low as 2 mol %. A chiral phosphoramidite ligand and the precise stoichiometry of heterogeneous base are key for high catalytic activity and linear regioselectivity. This protocol was applied in the atom- and step-economical synthesis of eight biologically active octaketide natural products, including anticancer drug candidate cytosporone B. Mechanistic studies provide insight on parameters affecting decarbonylation, a side reaction that limits the turnover number for catalytic hydroacylation. Deuterium labeling studies show that branched hydride insertion is fully reversible, whereas linear hydride insertion is largely irreversible and turnover-limiting. We propose that ligand (R a,R,R)-SIPHOS-PE effectively suppresses decarbonylation, and helps favor a turnover-limiting insertion, by lowering the barrier for reductive elimination in the linear-selective pathway. Together, these factors enable high reactivity and regioselectivity.
- Von Delius, Max,Le, Christine M.,Dong, Vy M.
-
supporting information
p. 15022 - 15032
(2012/11/06)
-
- An improved synthesis of hydroxy aryl ketones by fries rearrangement with methanesulfonic acid/methanesulfonic anhydride
-
Methanesulfonic acid treated with methanesulfonic anhydride effectively mediates the Fries rearrangement of aryl esters to give hydroxy aryl ketones with high yields. Georg Thieme Verlag Stuttgart · New York.
- Jeon, Ingyu,Mangion, Ian K.
-
experimental part
p. 1927 - 1930
(2012/10/08)
-
- Ligated regioselective PdII catalysis to access β-aryl-bearing aldehydes, ketones, and β-keto esters
-
By employing ligands in the PdII-mediated arylative isomerization of allyl alcohols, a milder and regioselective access to the versatile building blocks β-aryl aldehydes and ketones was developed. This new and chelation-controlled protocol enabled the compatibility of wide range of functionalities to generate dihydrochalcones, α-benzyl-α′- alkyl acetones, dihydrocinnamaldehydes, and α-benzyl β-keto esters (from Baylis-Hillman adducts). A practical multigram synthesis of an intermediate for Propafenone was also demonstrated. Copyright
- Vellakkaran, Mari,Andappan, Murugaiah M. S.,Kommu, Nagaiah
-
supporting information; experimental part
p. 4694 - 4698
(2012/09/22)
-
- Synthesis and biological evaluation of phloridzin analogs as human concentrative nucleoside transporter 3 (hCNT3) inhibitors
-
Nucleoside transporter inhibitors have potential therapeutic applications as anticancer, antiviral, cardioprotective and neuroprotective agents. Although quite a few potent inhibitors of the equilibrative nucleoside transporters are known, largely missing are the concentrative nucleoside transporter inhibitors. Phloridzin (3, Ki = 16.00 μM) is a known moderate inhibitor of the concentrative nucleoside transporters. We have synthesized and evaluated analogs of phloridzin at the hCNT3 nucleoside transporter. Within the series of synthesized analogs compound 16 (Ki = 2.88 μM), possessing a ribofuranose sugar unit instead of a glucopyranose as present in phloridzin, exhibited the highest binding affinity at the hCNT3 transporter. Phloridzin and compound 16 have also been shown to be selective for the hCNT3 transporter as compared with the hENT1 transporter. Compound 16 can serve as a new lead which after further modifications could yield selective and potent hCNT3 inhibitors.
- Gupte, Amol,Buolamwini, John K.
-
supporting information; experimental part
p. 917 - 921
(2009/09/06)
-
- Novel palladium-on-carbon/diphenyl sulfide complex for chemoselective hydrogenation: Preparation, characterization, and application
-
A diphenyl sulfide immobilized on palladium-on-carbon system, Pd/C[Ph 2S], was developed to achieve the highly chemoselective hydrogenation of alkenes, acetylenes, azides, and nitro groups in the presence of aromatic ketones, halides, benzyl esters, and N-Cbz protective groups. Instrumental analyses of the heterogeneous catalyst demonstrated that diphenylsul fide was embedded on Pd/C via coordination of its sulfur atom to palladium metal or physical interaction with graphite layers of the activated carbon. The catalyst could be recovered and reused at least five times without any significant loss of the reactivity.
- Mori, Akinori,Mizusaki, Tomoteru,Kawase, Masami,Maegawa, Tomohiro,Monguchi, Yasunari,Takao, Shinobu,Takagi, Yukio,Sajikia, Hironao
-
experimental part
p. 406 - 410
(2009/04/06)
-
- A ruthenium-catalyzed one-pot method for α-alkylation of ketones with aldehydes
-
Ketones react with an array of aldehydes in dioxane at 80 °C in the presence of a catalytic amount of RuCl2(PPh3)3 along with KOH to give the corresponding α-alkylated ketones in moderate to good yields. A reaction pathway involving base-catalyzed cross-aldol reaction between ketones and aldehydes to form α,β-unsaturated ketones and regioselective reduction of carbon-carbon double bond of α,β-unsaturated ketones is proposed for this catalytic process.
- Cho, Chan Sik,Shim, Sang Chul
-
p. 4329 - 4332
(2007/10/03)
-
- Pd-C/ammonium formate: A selective catalyst for the hydrogenation of chalcones to dihydrochalcones
-
Pd-C/ammonium formate is a highly efficient catalyst for the selective hydrogenation of chalcones to dihydrochalcones (DHCs). The reaction proceeds under mild conditions and the Pd-C catalyst is recovered without loss of activity.
- Ahmed, Naseem,Van Lier, Johan E.
-
p. 584 - 585
(2007/10/03)
-
- Candida rugosa lipase-mediated enantioselective acetylation studies on (±)-3-arylmethyl-3-hydroxymethyl-2,3-dihydro-1-benzopyran-4(H)-ones
-
Candida rugosa lipase, catalyzed enantioselective acetylation reactions have been performed on novel (±)-3-arylmethyl-3-hydroxymethyl-2,3- dihydrobenzopyran-4-ones in diisopropyl ether. The Candida rugosa lipase-catalyzed acetylations exhibit the enantiomeric separation of the racemic compounds 5a-g, the enantioselectivity of the reaction has been found to be highly dependent on the structure of the substrate. The enantiomeric excess (ee) values are determined by 1H NMR spectral analysis of their O-acetylmandelic acid esters and highest enantiomeric excess obtained is 79% in case of 5c.
- Trikha, Smriti,Kumar, Rajesh,Dhawan, Ashish,Poonam,Prasad, Ashok K.,Cholli, Ashok L.,Olsen, Carl E.,Watterson, Arthur C.,Parmar, Virinder S.
-
p. 356 - 365
(2007/10/03)
-
- Acaricidal activity of tonka bean extracts. Synthesis and structure-activity relationships of bioactive derivatives
-
The acaricidal effects of tonka bean, Dipterix odorata, extracts were investigated on Dermatophagoides pteronyssinus, the European house dust mite, and compared with benzyl benzoate as a standard acaricidal compound. A cyclohexane extract was the most effective, with an EC50 = 0.075 g/m2 after a 24 h period, as compared with benzyl benzoate (0.025 g/m2). Bioassay-guided fractionation of this extract led to the isolation of coumarin (1). Pharmacomodulation of this compound led us to test 20 analogues (2-21), which were either synthesized or purchased.
- Gleye, Christophe,Lewin, Guy,Laurens, Alain,Jullian, Jean-Christophe,Loiseau, Philippe,Bories, Christian,Hocquemiller, Reynald
-
p. 690 - 692
(2007/10/03)
-
- Alkylation of dianions derived from 2-(1-iminoalkyl) phenols: Synthesis of functionalized 2-acyl phenols
-
A method has been developed for the almost exclusive C-alkylation of the 2-(l-liminoalkyl) phenols 1, important organic compounds with a range of employment, which allows the preparation of complex derivatives 4 with good yields starting from easily available materials. The operational simplicity of this method take advantages in providing a variety of alkylated 2-acyl phenols 5 by an easy hydrolysis of the 2-(1-iminoalkyl) phenols 4.
- Cimarelli, Cristina,Palmieri, Gianni
-
p. 15711 - 15720
(2007/10/03)
-
- 4-derivatives coumarin-3-phosphonic acids and esters
-
In the Arbuzov reactions of 2′-bromoacetoxyphenone with trimethyl phosphite the derivatives in position 4 of 3-phosphonocoumarinic acids and esters were obtained.
- Kostka, Krzysztof,Pastuszko, Slawomir,Kotynski, Andrzej,Budzisz, Elzbieta
-
p. 199 - 209
(2007/10/03)
-
- Influence of the β-Substitution on the Photochemistry of α,2-Diacetoxystyrenes. Irradiatin of Phenyl, Vinyl, and Benzyl Derivatives
-
β-Substitution shows a pronounced influence on the photochemistry of α,2-diacetoxystyrenes.As in the case of the parent compound, intramolecular cyclization with participation of the neighbouring 2-acetoxy group takes place upon irradiation of the enol esters 4a-c; however other processes are also observed, depending on the substrate.The phenyl derivative 4a gives the E isomer 7a and the phenanthrene 9.The vinyl derivative 4b also undergoes cis-trans isomerization and/or photooxidation, to afford 7b and 10.Finally, a 1,4-acyl migratin occurs in the benzyl derivative 4c, whereby the 1,4-diketone 12 is formed.
- Alvaro, Mercedes,Baldovi, Vicenta,Garcia, Hermenegildo,Miranda, Miguel, A.,Primo, Jaime
-
p. 267 - 274
(2007/10/02)
-
- Synthesis and angioprotective, antiallergic and antihistaminic activities of 3-benzyl-chromones (homoisoflavones)
-
Various 3-benzyl-chromones were prepared and their angioprotective antiallergic and antihistaminic activities were studied. - 3-benzyl-chromones / antiallergic / antihistaminic / angioprotective
- Kirkiacharian, Serge,Tongo, Hubert G.,Bastide, Janine,Bastide, Pierre,Grenie, Marie Magdeleine
-
p. 541 - 546
(2007/10/02)
-
- Use of Nitrile Oxides in Synthesis. A Novel Synthesis of Chalcones, Flavanones, Flavones and Isoflavones
-
Novel methodology is developed for a three-step synthesis of chalcones, flavanones, flavones and isoflavones. 1.Salicylaldoxime is chlorinated to the corresponding hydroxamoyl chloride in the presence of pyridine, and cycloadded to styrene and phenylacetylene. 2.The isoxazole derivatives formed are reductively cleaved over Raney-Ni to β-hydroxyketones or 1,3 diketones. 3.Acid-catalyzed cyclization gives the flavonoids.Use of ω-methoxy- or ω-dialkylamino-substituted styrenes (enamines) leads regioselectively to 4-aryl-substituted isoxazoles and derived isoflavones.
- Thomsen, Ib,Torssell, Kurt B. G.
-
p. 303 - 308
(2007/10/02)
-
- NAD(P)+-NAD(P)H Models. 64. The Quantitative Elucidation of the Mechanistic Aspects in the Silica Gel-Catalyzed Reduction of α,β-Unsaturated Carbonyl Compounds by a Model of NAD(P)H
-
Eight α,β-unsaturated carbonyl compounds, 1-(2'- or 4'-substituted phenyl)-3-phenyl-2-propen-1-ones (2'-or 4'-substituted chalcones), were subjected to the reduction by an NAD(P)H model in the presence of silica gel in benzene.All of these afforded quantitatively the corresponding saturated carbonyl compounds, whereas no 1,2-reduction took place.For 2'-methoxy, 4'-methyl, 4'-bromo, and 4'-nitro derivatives as well as the unsubstituted carbonyl compound, the apparent reactivity of the substrate increases with the increase in electronwithdrawing ability of the substituent, whereas the degree of the adsorption onto the surface of silica gel decreases.It is also apparent that the 4'-hydroxy derivative exerts lower reactivity than the 2'-hydroxy derivative in spite of much more efficient adsorption of the former.In order to uniformly interpret the apparent results, the data obtained were quantitatively analyzed in terms of kinetics as well as equilibrium constants for the adsorption of the substrates onto the surface of silica gel.It has been revealed that the silanol group on the surface of silica gel acts as a general-acid catalyst in the reduction.
- Yasui, Shinro,Fujii, Masayuki,Ohno, Atsuyoshi
-
p. 4019 - 4026
(2007/10/02)
-
- A NOVEL PHOTOCHEMICAL 1,4-ACYL MIGRATION IN ENOL ESTERS. THE PHOTOLYSIS OF ENOL ACETATES OF 3-PHENYLPROPIOPHENONES
-
Photolysis of the enol acetates 1a, b gives the 1,4-diketones 4a, b by a mechanism involving a primary homolytic carbonyl-oxygen bond cleavage, followed by 1,2-hydrogen shift and in cage recombination.
- Alvaro, M.,Baldovi, V.,Garcia, H.,Miranda, M. A.,Primo, J.
-
p. 3613 - 3614
(2007/10/02)
-
- Studies on the metabolism of propafenone. 1st comm.: Synthesis and chromatographic/mass spectrometric properties of the labelled compound and of the reference substances
-
The synthesis of 14C-propafenone and 2H-propafenone (propafenone: 2-(2'-hydroxy-3'-propylamino-propoxy)-ω-phenyl-propiophenone hydrochloride) and some reference compounds is described. The thin-layer chromatographic, high-performance liquid and gas chromatographic properties of the substances are described. Propafenone and the reference substances were studied by mass spectrometry and compared with each other, with respect to structural elucidation of the metabolites. The chromatographic and mass spectrometric data (key ions) enables the metabolites of propafenone to be identified in biological material.
- Hege,Weymann,Lietz
-
p. 843 - 849
(2007/10/02)
-
- Intramolecular Alkylation of Phenols. Part 5. A Regiospecific Anionic Ring Closure of Phenols via Quinone Methides
-
The bis-magnesium salts of the triols (6a) and (6h) cyclise when heated in benzene with high ortho-regiospecificity to the corresponding bis-phenols (7) and (8).The triols (6k) and (6o) under the same conditions cyclise with high para-regiospecificity to the corresponding bis-phenols (7) and (8).Both (6a) and (6h) cyclise via o-quinone methides, and (6k) and (6o) via p-quinone methides.Results from the use of, inter alia, 18-crown-6, indicate that the high ortho-regiospecificity of the cyclisation of (6a) and (6h) is due to intramolecular Mg(II) bridging of the intermediate o-quinone methides.The high para-regiospecificity of cyclisation of (6k) and (6o) is due to steric hindrance towards o-cyclisation of the intermediate p-quinone methides presented by the Mg(II) cation.The unexpected facility with which (6a) and (6k) undergo ring closure is discussed.
- Murphy, William S.,Wattanasin, Sompong
-
p. 1567 - 1577
(2007/10/02)
-