- Synthesis, activity and mechanism for double-ring conjugated enones
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The relationship between TLR4 and inflammation-related diseases has been paid more and more attention. The studies have shown that TLR4/NF-κB signaling pathway plays an important role in the transmission of inflammatory signals. A large number of pro-inflammatory factors, chemokines, adhesion factors, TLR4 and its ligands interact with each other, and jointly promote the development of diseases. In this work, 8 target compounds were synthesized to screen the inhibitory activity of TLR4 in vitro. The results of TLR4 inhibition test in vitro showed that the double-ring conjugated enones had a good inhibitory activity, and the IC50 value of compound 4f was 0.56 ± 0.10 μM, and it was superior to the positive control methotrexate. To further study the anti-inflammatory effect and mechanism of double-ring conjugated enones by using LPS induced rat synovial cell inflammation model. The results of the mechanism test showed that compound 4f could effectively promote the apoptosis of rat synovial cells, and the mechanism might be related to the up-regulation of the expression of apoptosis-related protein Caspase-3. In addition, compound 4f could significantly inhibit the increase of inflammatory factors TNF-α, IL-1β and IL-6 in rat synovial cells induced by LPS, showing a good anti-inflammatory activity. In the TLR4/NF-κB signaling pathway test of rat synovial cells, compound 4f can effectively regulate the expression levels of TLR4, MyD88, NF-κB and IκB related proteins in TLR4/NF-κB signaling pathway, which may be due to its inhibition of LPS-induced inflammation in rat synovial cells. At the same time, it inhibits the abnormal proliferation of cells and its important mechanism promoted of apoptosis.
- Chen, Guangying,Huang, Gangliang,Liu, Jian,Zhou, Shiyang
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Read Online
- Efficient and straightforward preparation of a building block for (-)-teubrevin G synthesis via chemically diversed oriented synthesis
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A rapid and efficient methodology to highly functionalised molecular units well suited as scaffolds for diversity-oriented molecular construction in the synthesis of natural products is reported herein. A key macrocyclic intermediate in the synthesis of the neo-clerodane diterpene (-)-teubrevin G was successfully synthesized in a 5-step sequence in a 70% overall yield using a novel intramolecular coupling between an allylborating agent and a 1,5-dialdehyde moiety.
- Velazquez, Daniel Garcia,Luque, Rafael
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Read Online
- Design, synthesis and anti-rheumatoid arthritis evaluation of double-ring conjugated enones
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Four series of double-ring conjugated enones were designed, synthesized and studied for the inhibition of synovial cell activity through the modification of Dysodensiol K core structure, double-ring, double-bond and double-carbonyl groups. For in vitro synovial cell assay of rats, compound 151 and 168 exhibited good inhibitory activities, with IC50 values of 2.71 ± 0.18 and 2.68 ± 0.16 μM respectively. At the same time, the LDH release and LD50 test results revealed that the target compounds were low cytotoxicity and acute toxicity. For in vivo CIA model test through the oral administration, compounds 151 and 168 were exhibited similar effect to positive control group methotrexate.
- Zhou, Shiyang,Zou, Huiying,Huang, Gangliang,Chen, Guangying,Zhou, Xueming,Huang, Shuheng
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- Preparation of pyridine derivatives from the corresponding 5-acetal-1-carbonyl compounds by acid promoted cyclization
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The synthesis of four alkylpyridine derivatives from 5-acetal-1-carbonyl compounds via the one-pot, acid-promoted cyclization of oxime intermediates is described. In addition, a dihydroxypyridine and pyridinium salt were also synthesized. The pyridine formation step was not affected by the stereochemistry of the precursors used.
- Konno, Hiroyuki,Mihara, Hiromichi,Watanabe, Yuki
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p. 1314 - 1329
(2021/07/19)
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- Br?nsted acidic cellulose-PO3H: An efficient catalyst for the chemoselective synthesis of fructones and trans-esterification via condensation of acetoacetic esters with alcohols and diols
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Cellulose is the most abundant organic source and has expedient a great deal of interest as renewable and emerged as sustainable feedstock. The functionalization of cellulose as designed catalytic system intriguing furnished to the production of fine chemicals. Herein, we synthesized an environmental friendly solid acid catalyst by functionalizing cellulose with phosphoric acid (PO3H). The successful functionalization of cellulose with PO3H was confirmed by 31P NMR, ICP-OES, FE-SEM, and XPS analysis. ICP-OES revealed the presence of phosphorus content of ～1.0 wt. % on the catalyst's surface while elemental mapping by FESEM and XPS shows a uniform distribution of phosphorus over the material. The synthesized solid acid catalyst was utilized for condensation of diols with acetoacetic esters in solvent-free conditions to synthesize fine chemicals. The present approach not only circumvented the one-step protection and other products but more fascinatingly provided trans-esterification of acetoacetic esters with diols and n-alcohols. The catalyst was successfully used for chemoselective protection on ethyl acetoacetate with 1, 2 diols to essential fructone molecule with ～100% conversion and 99% selectivity. The results suggested that the catalyst has the advantage over commercial solid acid heterogeneous and homogeneous catalysts.
- Naikwadi, Dhanaji R.,Singh, Amravati S.,Biradar, Ankush V.
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- Synthetic method of fructone compound
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The invention discloses a synthetic method of a fructone compound, and relates to the technical field of chemical synthesis. The synthetic method comprises the following step that a beta-keto ester compound reacts with a diol compound in the presence of an acidic cation exchange resin catalyst to generate a fructone compound. According to the synthetic method of the fructone compound, the acid cation exchange resin is adopted as the catalyst, the catalyst can be repeatedly used, catalysis is efficient, and selectivity is high.
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Paragraph 0036-0038; 0045-0047; 0057-0059; 0060-0069
(2020/07/13)
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- Total synthesis and anti-inflammatory evaluation of violacin A and its analogues
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A concise total synthesis of an exceedingly potent anti-inflammatory agent violacin A as well as the preparation of thirty analogues of this lead from commercially available orcinol are described. Highlights of our synthetic efforts involve Friedel-Crafts acylation, the regioselective etherification and esterification of phenolic hydroxyl groups, and Baker-Venkatamaran rearrangement to form basic skeleton of violacin A. The deprotection reaction with Pd-catalytic was involved to avoid the elimination of the hemiacetal hydroxyl at C2. In addition, all synthetic compounds were screened for anti-inflammatory activity against nitric oxide (NO) production using lipopolysaccharide (LPS)-induced Raw264.7 cells. A range of violacin A derivatives 11b, 11d, 11f, 12e, 12g, 13g, 17d-g exhibited stronger anti-inflammatory effect than that of violacin A. Notably, halogeno-benzyloxy substituent at C-7 were favourable for anti-inflammatory activities of violacin A derivatives. Additionally, Western blot results indicated halogeno-benzyloxy derivatives inhibited pro-inflammatory cytokines releases correlated with the suppression of NF-κB signaling pathway.
- Liu, Qingyin,Mu, Yu,An, Qi,Xun, Jiali,Ma, Jian,Wu, Wenxi,Xu, Minjuan,Xu, Jun,Han, Li,Huang, Xueshi
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- Unique photoaffinity probes to study TGFβ signaling and receptor fates
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A novel synthetic approach is used to prepare a diverse set of "first-in-class" dihydropyridine-based TGFβ receptor degraders bearing photoaffinity labels. These probes serve as valuable tools to study TGFβ receptor fates and dynamics-an important challenge in chemical biology.
- L?ngle,Wesseler,Fl?tgen,Leek,Plowright,Schade
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supporting information
p. 4323 - 4326
(2019/04/26)
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- COMPOSITIONS FOR THE TREATMENT OF HYPERTENSION AND/OR FIBROSIS
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The present invention relates to novel compounds and their use in the prophylactic and/or therapeutic treatment of hypertension and/or fibrosis.
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Paragraph 00104
(2018/04/20)
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- Design, synthesis and biological evaluation of multifunctional tacrine-curcumin hybrids as new cholinesterase inhibitors with metal ions-chelating and neuroprotective property
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Total sixteen tacrine-curcumin hybrid compounds were designed and synthesized for the purpose of searching for multifunctional anti-Alzheimer agents. In vitro studies showed that these hybrid compounds showed good cholinesterase inhibitory activity. Particularly, the potency of K3-2 is even beyond tacrine. Some of the compounds exhibited different selectivity on acetylcholinesterase or butyrylcholinesterase due to the structural difference. Thus, the structure and activity relationship is summarized and further discussed based on molecular modeling studies. The ORAC and MTT assays indicated that the hybrid compounds possessed pronounced antioxidant activity and could effectively protect PC12 cells from the H2O2/Aβ42-induced toxicity. Moreover, the hybrid compounds also showed positive metal ions-chelating ability in vitro, suggesting a potential to halt ion-induced Aβ aggregation. All the obtained results demonstrated that the tacrine-curcumin hybrid compounds, in particular compound K3-2, can be considered as potential therapeutic agents for Alzheimer's disease.
- Liu, Zhikun,Fang, Lei,Zhang, Huan,Gou, Shaohua,Chen, Li
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p. 2387 - 2398
(2017/04/03)
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- Chitosan grafted with a heteropolyanion-based ionic liquid as an effective and reusable catalyst for acetalization
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Chitosan immobilized with an acidic ionic liquid (CS-VImPS-PW) was fabricated via a radical addition reaction of N-vinylimidazoliumpropane sulfonate and chitosan, followed by acidification with a heteropolyacid. It was characterized by a Fourier transform infrared spectrometer, solid-state 13C nuclear magnetic resonance spectrometer, thermogravimetric analyzer, elemental analyzer, and Hammett indicator. Some acetalization reactions were investigated to evaluate the catalytic activity of CS-VImPS-PW. The results show that CS-VImPS-PW is highly active for the acetalization reactions in high acetal yields ranging from 83.2 to 96.2% and can be reused 8 times without noticeable loss of activity.
- Zhang, Wei-Hong,Liu, Shan-Shan,Liu, Ping,Xu, Jie,Xue, Bing,Wei, Xian-Yong,Li, Yong-Xin
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p. 41404 - 41409
(2016/05/19)
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- Synthesis of natural maleimides farinomaleins C-E and evaluation of their antifungal activity
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A practical and convenient synthesis of naturally occurring farinomaleins C-E was achieved starting from readily available ethyl 3-methyl-2-oxobutyrate and triethyl phosphonoacetate. The key steps of the sequence included a Horner-Wadsworth-Emmons condensation to obtain the precursor farinomalein A and coupling with suitable alcohols to install the chain. The synthesis of farinomalein D has been achieved starting from (R)-isopropylideneglycerol on the basis of which the S configuration was assigned to the natural compound. The antifungal activity of the synthesized compounds was evaluated against Cladosporium cladosporioides.
- Lahore, Santosh,Aiwale, Sachin T.,Sardi, Paola,Dallavalle, Sabrina
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p. 4196 - 4198
(2014/07/22)
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- Synthesis of natural maleimides farinomaleins C-E and evaluation of their antifungal activity
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A practical and convenient synthesis of naturally occurring farinomaleins C-E was achieved starting from readily available ethyl 3-methyl-2-oxobutyrate and triethyl phosphonoacetate. The key steps of the sequence included a Horner-Wadsworth-Emmons condensation to obtain the precursor farinomalein A and coupling with suitable alcohols to install the chain. The synthesis of farinomalein D has been achieved starting from (R)-isopropylideneglycerol on the basis of which the S configuration was assigned to the natural compound. The antifungal activity of the synthesized compounds was evaluated against Cladosporium cladosporioides.
- Lahore, Santosh,Aiwale, Sachin T.,Sardi, Paola,Dallavalle, Sabrina
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p. 4196 - 4198
(2015/02/05)
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- Facile synthesis of fructone from ethyl acetoacetate and ethylene glycol catalyzed by SO3H-functionalized Bronsted acidic ionic liquids
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SO3H-functionalized Bronsted acidic ionic liquids (BAILs) were synthesized and utilized as highly efficient catalysts for the production of fructone via the acetalization reaction of ethyl acetoacetate with ethylene glycol. In comparison with conventional H2SO4 and cation exchange resins, the BAILs N-(4-sulfonic acid) butyl triethylammonium hydrogensulfate ([BSEt3N][HSO4]) of strong acidities exhibited excellent catalytic activities. The effects of various parameters such as different BAILs, reaction temperature, catalyst dosage, and molar ratio of the reactants on the conversion of ethyl acetoacetate were investigated in detail. The experimental results indicated that the catalytic performance of BAILs were closely related to their Hammett acidities. Moreover, it was found that [BSEt3N][HSO4] could be also recovered easily and used repetitively six times without obvious decline in activity and quantity, showing great potential application in industry. This journal is the Partner Organisations 2014.
- Liu, Yong,Wang, Yi-Tao,Liu, Tao,Tao, Duan-Jian
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p. 22520 - 22525
(2014/06/23)
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- Condensation reactions assisted by acidic hydrogen bonded hydroxyl groups in solid tin(ii)hydroxychloride
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Tin(ii)hydroxychloride is reported as a heterogeneous Bronsted acid catalyst. Sn(OH)Cl was synthesized by a precipitation method and characterized by XRD, FT-IR, 1H MAS NMR, SEM, TG-DTA and N2 sorption. The acidity measurements of tin(ii)hydroxychloride by FT-IR pyridine adsorption and 1H MAS NMR showed the presence of Bronsted acidity. The Bronsted acidity can be attributed to strong hydrogen bonding between the -OH and Cl groups. Sn(OH)Cl showed high activity for important condensation reactions such as the Prins condensation, Claisen-Schmidt condensation and ketalization. The catalytic activity of Sn(OH)Cl was compared with that of SnO, SnO2 and Sn2(OH)2O. The catalyst was recycled three times with a negligible decrease in activity. The Royal Society of Chemistry 2013.
- Marakatti, Vijaykumar S.,Shanbhag, Ganapati V.,Halgeri, Anand B.
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p. 10795 - 10800
(2013/09/02)
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- A shimizu non-aldol approach to the formal total synthesis of palmerolide A
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A formal total synthesis of palmerolide A has been accomplished by assembling three fragments by means of successive Julia-Kocienski olefination, Yamaguchi esterification, and ring-closing metathesis (RCM). Our initial efforts to combine the first two fragments through a Julia-Kocienski reaction between a secondary sulfone and a ketone were not successful; nevertheless, it was feasible between a primary sulfone and aldehyde. Yamaguchi esterification with the third fragment then set the stage for a RCM reaction. Initial failure of the RCM with a PMB-ether adjacent to the olefins and the difficulty in cleaving the PMB-ether prompted us to change the choice of protecting groups, which then paved the way to the macrocyclic core of palmerolide A.
- Pujari, Sandip A.,Gowrisankar, Parthasarathy,Kaliappan, Krishna P.
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scheme or table
p. 3137 - 3151
(2012/08/28)
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- Highly efficient procedure for the synthesis of fructone fragrance using a novel carbon based acid
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The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high activity for the reaction, giving a yield of over 95%. The advantages of high activity, stability, reusability and low cost for a simple synthesis procedure and wide applicability to various diols and β-keto esters make this novel carbon based acid one of the best choices for the reaction.
- Hu, Baowei,Li, Chunqing,Zhao, Sheng-Xian,Rong, Lin-Mei,Lv, Shao-Qin,Liang, Xuezheng,Qi, Chenze
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experimental part
p. 5369 - 5377
(2010/12/25)
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- ORGANIC COMPOUNDS
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Disclosed are compounds having the ability to modulate, namely to improve, enhance and or modify fragrance compositions due to their ability to inhibit cytochrome P450 enzymes, e.g. CYP2A13 and CYP2B6.
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Page/Page column 34-35
(2008/12/04)
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- Methods for the synthesis of carbon-13 labelled acids and esters
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Syntheses of isotopically labelled putative biosynthetic intermediates to the natural products monocerin 1, hectochlorin 2 and strobilurin A 3 are described. For the preparation of [9,10-13C2] dihydroisocoumarin 10, a stereoselective aldol condensation of 13C2-acetylated chiral auxiliary 5 was used to assemble the labelled C9-C14 fragment. The preferred approaches to the syntheses of [1,2-13C2]5,5-dichlorohexanoic acid 15 and the N-acetylcysteamine derivative of [1,2-13C2]cinnamic acid 19 involved a Horner-Wadsworth-Emmons chain extension and Knoevenagel reaction, respectively. Copyright
- Jordan, Angela C.,Axford, Lorraine C.,Harding, John R.,O'Connell, Yvonne,Simpson, Thomas J.,Willis, Christine L.
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p. 338 - 341
(2008/02/08)
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- Polysubstituted oxygen heterocycles by a Reformatsky-type reaction/reductive cyclization approach from enantiopure β-ketosulfoxides
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(Chemical Equation Presented) The stereoselective synthesis of tetrasubstituted tetrahydrofurans and trisubstituted tetrahydropyrans bearing a sulfoxide was achieved by reductive cyclization (Et3SiH/TMSOTf) from the corresponding enantiopure hydroxy ketones protected as a dioxolane. These derivatives are easily accessible from a Reformatsky-type reaction between α-bromo-α′-sulfinyl ketones and protected α- or β-ketoaldehydes, followed by diastereoselective reduction of the resulting β-ketosulfoxide.
- Colobert, Francoise,Choppin, Sabine,Ferreiro-Mederos, Leticia,Obringer, Michel,Arratta, Sandra Luengo,Urbano, Antonio,Carreno, M. Carmen
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p. 4451 - 4454
(2008/03/11)
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- Total synthesis of topopyrones B and D
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(Chemical Equation Presented) We describe a straightforward synthesis of topopyrones B and D, which are potent and selective inhibitors of topoisomerase I. The chemistry should be suitable for additional structure-activity relationship (SAR) work.
- Tan, Jason Samuel,Ciufolini, Marco A.
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p. 4771 - 4774
(2007/10/03)
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- Enantioselective microbial hydrolysis of dissymmetrical cyclic carbonates with disubstitution
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Enantioselective microbial hydrolysis of C1 and C2 dissymmetrical cyclic carbonates with disubstitution (methyl and another groups) has been developed. Pseudomonas diminuta (FU0090), a bacterium, efficiently catalyzes the hydrolysis of five-membered cyclic carbonates. While the trans-substrates are hydrolyzed with low enantioselectivities and/or reactivities, the microbe hydrolyzes the cis-substrates with very high enantioselectivities to afford the corresponding almost optically pure anti-(2R,3S)-diols. On the other hand, six-membered trans-cyclic carbonates are enantioselectively hydrolyzed to afford the corresponding optically active syn-(2R,4R)-diols, although the hydrolysis of the cis-substrates gives racemic compounds. In all cases, the enzyme prefers the (R)-enantiomer for the carbon atom bearing a methyl group.
- Nogawa, Masaki,Sugawara, Satomi,Iizuka, Rie,Shimojo, Megumi,Ohta, Hiromichi,Hatanaka, Minoru,Matsumoto, Kazutsugu
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p. 12071 - 12083
(2007/10/03)
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- Total syntheses of amphidinolide X and Y
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Concise total syntheses of the cytotoxic marine natural products amphidinolide X (1) and amphidinolide Y (2) as well as of the nonnatural analogue 19-epi-amphidinolide X (47) are described. A pivotal step of the highly convergent routes to these structurally rather unusual secondary metabolites consists of a syn-selective formation of allenol 17 by an iron-catalyzed ring opening reaction of the enantioenriched propargyl epoxide 16 (derived from a Sharpless epoxidation) with a Grignard reagent. Allenol 17 was then cyclized with the aid of Ag(I) to give dihydrofuran 19 containing the (R)-configured tetrasubstituted sp3 chiral center at C. 19, which was further elaborated into tetrahydrofuran 25 representing the common heterocyclic motif of 1 and 2. The aliphatic chain of amphidinolide X featuring an anti-configured stereodiad at C. 10 and C. 11 was generated by a palladium-catalyzed, Et 2Zn-promoted addition of the enantiopure propargyl mesylate 29 to the functionalized aldehyde 28. The preparation of the corresponding C.1-C.12 segment of amphidinolide Y relies on asymmetric hydrogenation of an α-ketoester, a diastereoselective boron aldol reaction, and a chelate-controlled addition of MeMgBr in combination with suitable oxidation state management for the elaboration of the tertiary acyloin motif. Importantly, the end games of both total syntheses follow similar blueprints, involving key fragment coupling processes via the "9-MeO-9-BBN" variant of the alkyl-Suzuki reaction and final Yamaguchi esterifications to forge the 16-membered macrodiolide ring of amphidinolide X and the 17-membered macrolide frame of amphidinolide Y, respectively. This methodological convergence ensures high efficiency and an excellent overall economy of steps for the entire synthesis campaign.
- Fuerstner, Alois,Kattnig, Egmont,Lepaqe, Olivier
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p. 9194 - 9204
(2007/10/03)
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- The synthesis of (4E)-N-(4-chlorophenyl)-5-substituted-2-diazo-3-oxopent-4- enoic acid amides
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The (4E)-N-(4-chlorophenyl)-5-(3-chlorophenyl)-2-diazo-3-oxopent-4-enoic acid amides 5a～j were synthesized with N-(4-chlorophenyl)-2-diazo-3- oxobutyramide 4 from p-chloroaniline and various arylaldehydes. The yielded products 5a～j were investigated with NMR, MS, IR, and X-ray crystal lo graphic techniques.
- Dong, Heng-Shan,Wang, Dong-Dong,Jin, Chi-Qiong
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p. 1011 - 1016
(2007/10/03)
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- The synthesis and crystal structure of (4E)-5-(3-chlorophenyl)-N-(4- chlorophenyl)-2-diazo-3-oxopent-4-enoic acid amide
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(4E)-5-(3-Chlorophenyl)-N-(4-chlorophenyl)-2-diazo-3-oxopent-4-enoic acid amide (5) was synthesized from p-chloroaniline to N-(4-chlorophenyl)-2-diazo-3- oxo-butyramide (4) with 3-chlorobenzaldehyde. The yielded product 5 was investigated with X-ray crystallographic, NMR, MS, and IR techniques. Compound 5 (C17H11Cl2N3O2, Formula wt = 360.19), crystallizes in the monoclinic space group P21/c with unit cell parameters a = 10.516(2), b = 17.996(4), c = 8.902(2) A, α = 90.00, β = 105.36(3), γ = 90.00°. V = 1624.5(6) A3, Z = 4, Dx = 1.473Mg m-3. The final R was 0.0511.
- Dong, Heng-Shan,Wang, Dong-Dong,Jin, Chi-Qiong
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p. 897 - 901
(2007/10/03)
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- Polyaniline-Supported Sulfuric Acid Salt as a Powerful Catalyst for the Protection and Deprotection of Carbonyl Compounds
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Structurally different carbonyl compounds were converted into their corresponding cyclic acetals using polyaniline-sulfate salt as catalyst in dry toluene in excellent yield. In turn, useful deacetalization in aqueous medium was demonstrated. Chemoselective protection of carbonyl compounds was also demonstrated. The advantages of the polyaniline-sulfate salt are ease of preparation and handling, stability, reusability and activity.
- Palaniappan, Srinivasan,Narender, Puli,Saravanan, Chandrasekaran,Rao, Vaidya Jayathirtha
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p. 1793 - 1796
(2007/10/03)
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- Regio- and diastereoselective synthesis of lissoclinolide analogues by Lewis acid catalyzed cyclization of the first 1,5-bis(trimethylsilyloxy)-1,3,5-hexatrienes with oxalyl chloride
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The Lewis acid catalyzed cyclization of 1,5-bis(trimethylsilyloxy)-1,3,5-hexatrienes with oxalyl chloride resulted in formation of polyunsaturated butenolides.
- Langer,Freifeld
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p. 523 - 525
(2007/10/03)
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- Zeolites for the Production of Fine Chemicals: Synthesis of the Fructone Fragrancy
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Fructone (ethyl 3,3-ethylendioxybutyrate), a flavouring material, has been obtained by acetalization of ethyl acetoacetate with ethylene glycol using different microporous and mesoporous aluminosilicates as catalysts. Tridirectional zeolites (Y and Beta) are very effective and selective for carrying out this reaction. It has been found that a higher concentration of acid sites does not guarantee a better catalytic performance and the hydrophobic-hydrophilic properties of the material play a determinant role in this reaction due to the different polarity of the reactants. The coupling between the concentration of active sites and the adequate adsorption properties is achieved for Beta zeolites with a Si/Al ratio between 25 and 50. Optimisation of reaction conditions and the appropriate catalyst allow us to obtain fructone with conversions and selectivities close to 100%.
- Climent,Corma,Velty,Susarte
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p. 345 - 351
(2007/10/03)
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- Synthesis and immunosuppressive activity of 2-substituted 2- aminopropane-1,3-diols and 2-aminoethanols
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A series of 2-substituted 2-aminopropane-1,3-diols was synthesized and evaluated for their lymphocyte-decreasing effect and immunosuppressive effect on rat skin allograft. A phenyl ring was introduced into the alkyl chain of the lead compound 3, which is an immunosuppressive agent structurally simplified from myriocin (1, ISP-I) via compound 2. The potency of the various compounds was dependent upon the position of the phenyl ring within the alkyl side chain. The most suitable length between the quaternary carbon atom and the phenyl ring was two carbon atoms. 2-Substituted 2-aminoethanols were successively synthesized and evaluated for their T-cell-decreasing effect and immunosuppressive effect using a popliteal lymph node gain assay in rats. The absolute configuration at the quaternary carbon affected the activity, and the (pro-S)-hydroxymethyl group of compound 6 was essential for potent immunosuppressive activity. Favorable substituents for the (pro-R)- hydroxymethyl group of 6 were hydroxyalkyl (hydroxyethyl and hydroxypropyl) or lower alkyl (methyl and ethyl) groups. 2-Amino-2-[2-(4- octylphenyl)ethyl]propane-1,3-diol hydrochloride (6, FTY720) was found to possess considerable activity and is expected to be useful as an immunosuppressive drug for organ transplantation.
- Kiuchi, Masatoshi,Adachi, Kunitomo,Kohara, Toshiyuki,Minoguchi, Masanori,Hanano, Tokushi,Aoki, Yoshiyuki,Mishina, Tadashi,Arita, Masafumi,Nakao, Noriyoshi,Ohtsuki, Makio,Hoshino, Yukio,Teshima, Koji,Chiba, Kenji,Sasaki, Shigeo,Fujita, Tetsuro
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p. 2946 - 2961
(2007/10/03)
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- Synthesis of tetrahydrofurans by a tandem hydrogen atom abstraction/ radical nucleophilic displacement sequence
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(equation presented) The reaction of a series of 5-(N-phthalimidoxy)-1-phenyl-1-(diphenylphosphatoxy)pentanes with triphenyltin hydride and AIBN provides alkoxy radicals which undergo 1,5-hydrogen atom abstraction to give β-(phosphatoxy)alkyl radicals. These radicals then take part in a radical nucleophilic displacement leading, after chain transfer, to tetrahydrofurans.
- Crich, David,Huang, Xianhai,Newcomb, Martin
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p. 225 - 227
(2008/02/12)
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- Montmorillonite Clay Catalysis. Part 2. 1 An Efficient and Convenient Procedure for the Preparation of Acetals catalysed by Montmorillonite K-10
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Acetalization of aldehydes and ketones is catalysed by montmorillonite K-10 in refluxing benzene or toluene in excellent yields.
- Li, Tong-Shuang,Li, Sheng-Hui,Li, Ji-Tai,Li, Hui-Zhang
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- Three- and Four-Carbon Elongating Ring Expansion of Cyclic Acetals to Medium-Sized Dioxacycloalkenones. Use of the Intramolecular Formation of Oxonium Ylides
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The Rh(II)-catalyzed reaction of 2-(3′-diazo-2′-oxopropyl)-2-methyldioxolane (1) in the presence of a protic nucleophile (NuH) such as AcOH resulted in effective ring enlargement to give the 8-membered 3-acetoxydioxocanone 4a (41%) and dioxocan-2-en-1-one 3 (46%). Similar treatment of 2-(4′-diazo-3′-oxobutyl)-2-methyldioxolane (9) with AcOH gave 4-acetoxydioxonanone 10 (67%), which was readily hydrolyzed on silica gel to a tautomeric mixture of hydrolysis products 16a and 16b (total yield 46%). In contrast, similar treatment of 2-(5′-diazo-4′-oxopentyl)-2-methyldioxolane (19) gave 2,5-dioxa-1-methyldecalin-7-one (20, 24%), and the yield increased to 61% in the absence of AcOH, by Stevens rearrangement. The reaction of 1,3-dioxane homologues 26 and 31 gave similar results. All of these reactions can be explained in terms of the intermediacy of bicyclooxonium ylides, which undergo either a Stevens rearrangement or, after protonation by a NuH, ring enlargement through release of the strain of the bicyclic ylides. Evidence of the reversible formation of oxonium ylides is also provided.
- Oku, Akira,Murai, Nobuhito,Baird, Julia
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p. 2123 - 2129
(2007/10/03)
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- Polyvinylogation Reagents: 1-Lithio-4-trimethylsiloxy-penta-1,3-diene and 1-Lithio-4-ethoxy-2-methyl-buta-1,3-diene
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Title products, lithiodienol ethers 6a and 7a, synthetic equivalents of 4-lithio pent-3-ene-2-one and 4-lithio-senecialdehyde were obtained by bromine-lithium exchange.They are choice reagents for the transformations 1 -> 2 and 1 -> 3, respectively.
- Duhamel, Lucette,Ancel, Jean-Erick
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p. 9237 - 9250
(2007/10/02)
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- Thermostable Enzymes in Organic Synthesis, Part 6. Total synthesis of (S)-(-)-Zearalenone using a TBADH-Generated Trifunctional Chiron
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Chiral alcohols produced by Thermoanaerobium brockii alcohol dehydrogenase (TBADH)-catalysed asymmetric reduction of polyfunctional ketones are useful building blocks for natural products synthesis.In particular, the ability of TBADH to discriminate between two ketones having equal chemical reactivity is demonstrated by enzymatic reduction of dec-9-ene-2,6-dione to produce optically pure (S)-2-hydroxydec-9-en-6-one.The total synthesis of (S)-(-)-zearalenone with optical purity that exceeds 99.5percent has been achieved by using the latter compound as a starting material.
- Keinan, Ehud,Sinha, Subhash C.,Sinha-Bagchi, Anjana
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p. 3333 - 3340
(2007/10/02)
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- Cyclic acetals or ketals of 8-keto esters or amides
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Compounds of formula I STR1 in conjunction with compounds that donate acid when exposed to actinic radiation, are suitable for use as positive photoresists. In formula I, R1 and R2 are hydrogen, alkyl, aryl, cycloalkyl, aralkyl or alkaryl, R3 to R8 are hydrogen or lower alkyl, X is --O-- or --NR9 --, where R9 is hydrogen or C1 -C4 alkyl n is 0 or 1, m is 2, 3 or 4 and Q is an organic radical of valency m. The photoresists are suitable for making printing formes, printed circuits, integrated circuits or silver-free photographic films.
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- 4-BROMO-2-ACETOKETAL-1-BUTYLALDEHYDE: AN ELEGANT KEY INTERMEDIATE FOR THE SYNTHESIS OF 4-DEMETHOXY-7,9-DIDEOXYDAUNOMYCINONE BY MARSCHALK REACTION
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Marschalk reaction of leucoquinizarin (2) with readily obtainable 4-bromo-2-acetoketal-1-butyraldehyde (3), from ethyl acetoacetate or acetone, gave in one step 4-demethoxy-7,9-dideoxydaunomycinone (1a) in 60percent yield.
- Ayyangar, N. R.,Mehendale, A. R.,Argade, A. B.
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p. 1959 - 1964
(2007/10/02)
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- Asymmetric Synthesis of (1S,3S,5R)-1,3-Dimethyl-2,9-dioxabicyclononane Mediated by Fermenting Bakers' Yeast
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Optically active (1S,3S,5R)-1,3-dimethyl-2,9-dioxabicyclononane has been synthesized in short steps including regio- and enantioselective reduction of 1,3-diketones by actively fermenting bakers' yeast.
- Ohta, Hiromichi,Ozaki, Kazuhiko,Tsuchihashi, Gen-ichi
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p. 2225 - 2226
(2007/10/02)
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- AN EFFICIENT, REGIOSPECIFIC SYNTHESIS OF (+/-)-DAUNOMYCINONE
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The development of a general strategy for the control of regiochemistry in the Diels-Alder reactions of substituted naphthazarins is described.Application of this strategy to the synthesis of (+/-)-daunomycinone (2) employs two successive regiochemically controlled Diels-Alder reactions and leads to a ten-step, regiospecific synthesis of (+/-)-2 in 36percent overall yield (Scheme 4).
- Kelly, T. Ross,Ananthasubramanian, L.,Borah, Kripinath,Gillard, John W.,Goerner, Richard N.,et al.
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p. 4569 - 4578
(2007/10/02)
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- REACTIVITE DES DERIVES DE CYCLOPROPYLIDENE-3 PROPYLE-I. SYNTHESE D'ALCOOLS β-CYCLOPROPYLIDENIQUES
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A series of β-cyclopropylidenic alcohols has been synthesized through the following sequence:(i) Wittig condensation between cyclopropylidenetriphenylphosphorane with appropriate monoprotected 1,3-dicarbonyl compounds; (ii)smooth hydrolysis of acetals (after necessary transacetalization step) and ketals thus formed; (iii) LAH reduction of aldehydes and ketones(yielding primary and secondery alcohols respectively) or treatment of ketones with methyllithium (yielding tertiary alcohols).
- Bertrand, M.,Leandri, G.,Meou, A.
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p. 1703 - 1710
(2007/10/02)
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