- Reactions of [2-(2-Naphthyl)phenyl]acetylenes and 2-(2-Naphthyl)benzaldehyde O-Phenyloximes: Synthesis of the Angucycline Tetrangulol and 1,10,12-Trimethoxy-8-methylbenzo[c]phenanthridine
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The Suzuki–Miyaura coupling reaction between (1,4,5-trimethoxynaphthalen-2-yl)boronic acid and 2-iodo-3-methoxy-5-methylbenzaldehyde gave the intermediate 3-methoxy-5-methyl-2-(1,4,5-trimethoxynaphthalen-2-yl)benzaldehyde. Conversion of this benzaldehyde
- Ngwira, Kennedy J.,Rousseau, Amanda L.,Johnson, Myron M.,de Koning, Charles B.
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Read Online
- Synthesis of a landomycinone skeleton via Masamune-Bergmann cyclization
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In this report, a synthetic study of landomycinone via Masamune-Bergmann cyclization is described. A 10-membered 1,2-dialkynylbenzene derivative was designated as a key intermediate in the formation of an angular tetracyclic core via Masamune-Bergmann cyclization. Cyclization was expected to proceed under mild heating conditions based on a DFT transition state analysis of the 10-membered enediyne. The enediyne was successfully prepared by intramolecular NHK cyclization in good yield and underwent Masamune-Bergman cyclization at 70 °C for 2 h. However, an undesired β-elimination of the secondary alcohol was involved in the cyclization. In addition, iodination at the 12 position did not occur due to the steric hindrance of two methyl groups. This methodology should be widely applicable to the synthesis of various types of highly oxy-functionalized anthraquinone derivatives as well as landomycinone, and should be a useful way to clarify structure-activity relationships. the Partner Organisations 2014.
- Yamaguchi, Sho,Tanaka, Hiroshi,Yamada, Ryo,Kawauchi, Susumu,Takahashi, Takashi
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Read Online
- Roles of the synergistic reductive O-methyltransferase GilM and of O-methyltransferase GilMT in the gilvocarcin biosynthetic pathway
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Two enzymes of the gilvocarcin biosynthetic pathway, GilMT and GilM, with unclear functions were investigated by in vitro studies using purified, recombinant enzymes along with synthetically prepared intermediates. The studies revealed GilMT as a typical
- Tibrewal, Nidhi,Downey, Theresa E.,Van Lanen, Steven G.,Ul Sharif, Ehesan,O'Doherty, George A.,Rohr, Juergen
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supporting information; experimental part
p. 12402 - 12405
(2012/09/05)
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- Efficient discovery of potent anti-HIV agents targeting the Tyr181Cys variant of HIV reverse transcriptase
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Non-nucleoside reverse transcriptase inhibitors (NNRTIs) that interfere with the replication of human immunodeficiency virus (HIV) are being pursued with guidance from molecular modeling including free-energy perturbation (FEP) calculations for protein-in
- Jorgensen, William L.,Bollini, Mariela,Thakur, Vinay V.,Domaoal, Robert A.,Spasov, Krasimir A.,Anderson, Karen S.
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supporting information; scheme or table
p. 15686 - 15696
(2011/12/03)
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- NEW BRADYKININ B1 ANTAGONISTS
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The invention relates to compounds of formula (I) where in R1, R1a, R1b, R2, R3 and X, X1, X2, X3 have the meaning as cited in the description and the claims. Said compounds are useful as Bradykinin B1 antagonists. The invention also relates to pharmaceutical compositions, the preparation of such compounds as well as the production and use as medicament.
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Page/Page column 162
(2010/04/03)
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- The first total synthesis of (±)-γ-herbertenol, a herbertene isolated from a non-herbertus source
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The structure of the aromatic sesquiterpene, (±)-γ- herbertenol, the first herbertane to be isolated from a non-herbertus source, was confirmed by a total synthesis, employing a Claisen rearrangement and ring-closing metathesis. Georg Thieme Verlag Stuttg
- Srikrishna,Ravikumar
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- GFAT INHIBITORS
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Compounds of formula (I) are provided as well as pharmaceutically acceptable salts and esters thereof, wherein the substituents are as disclosed in the specification. The compounds have utility for the treatment of type 2 diabetes mellitus.
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- AMINO ACID DERIVATIVES AND THEIR USE AS THROMBIN INHIBITORS
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There is provided compounds of formula I, wherein R 1, R 2, R 3, R x, Y, n and B have meanings given in the description which are useful as competitive inhibitors of trypsin-like proteases, such as thrombin, and in particular in the treatment of conditions where inhibition of thrombin is required as in thrombosis or as anticoagulants.
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- N-(4- carbamimidoyl-phenyl) -glycine derivatives
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The invention is concerned with novel N-(4-carbamimidoyl-phenyl)-glycine derivatives of the formula: wherein R1, E, X1 to X4 and G1 and G2 are as defined in the description and the claims, as well as hydrates or solvates and physiologically usable salts thereof.
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- An intramolecular arylation route to the kinafluorenones
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Intramolecular palladium-mediated arylation approaches to benzo[b]fluorenes have been investigated. The methodology has been applied in a short synthesis of kinafluorenone 2, providing an effective alternative to Friedel-Crafts-based approaches. (C) 2000 Elsevier Science Ltd.
- Qabaja, Ghassan,Jones, Graham B.
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p. 5317 - 5320
(2007/10/03)
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- Regioselective lactonization of naphthoquinones: Synthesis and antitumoral activity of the WS-5995 antibiotics
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An acid promoted quinolactonization of naphthoquinones has been developed, providing direct access to either ortho or para isomers as desired. Application of this methodology in syntheses of the antibiotics WS- 5995A, WS-5995C and functional analogs is demonstrated. Preliminary antitumoral activity of the analogs is presented together with electrochemical analysis. (C) 2000 Elsevier Science Ltd.
- Qabaja, Ghassan,M. Perchellet, Elisabeth,Perchellet, Jean-Pierre,Jones, Graham B.
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p. 3007 - 3010
(2007/10/03)
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- Modular Approach to the Accelerated Convergent Growth of Laser Dye-Labeled Poly(aryl ether) Dendrimers Using a Novel Hypermonomer
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The synthesis of novel dendrimers functionalized with laser dyes both at the periphery and at the core, along with all relevant model compounds necessary for accurate photophysical studies, is described. The utilized synthetic strategy involves a modular approach in which a variety of peripheral and core moieties can be placed on a dendritic structure bearing electrophilic peripheral groups and a nucleophilic core. Specifically, the target macromolecules required functionalization with the laser dyes coumarin 2 (periphery) and coumarin 343 (core) due to the possibility of energy transfer from the former to the latter dye. In addition, the preparation of a novel, highly soluble and reactive hypermonomer utilized in the rapid and efficient synthesis of high-generation dye-labeled dendrimers and model compounds is outlined.
- Gilat, Sylvain L.,Adronov, Alex,Frechet, Jean M. J.
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p. 7474 - 7484
(2007/10/03)
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- Exploratory studies on the synthesis of the unusual diterpenoid tropone harringtoriolide
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Various approaches to the total synthesis of the unusual diterpenoid tropone (2), discovered in the yew species Cephalotaxus harringtonia and C. hainanensis, are described. The rhodium-catalysed intramolecular cyclopropanation reaction of an ary1 ring by
- Rogers, Daniel H.,Frey, Barbara,Roden, Francis S.,Russkamp, Friedrich-Wilhelm,Willis, Anthony C.,Mander, Lewis N.
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p. 1093 - 1108
(2007/10/03)
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- Total syntheses of O4,O9-dimethylstealthins A and C
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O12-Acetyl-O4,O9-dimethylstealthin A (2-acetoxymethyl-11-amino-5-hydroxy-4,9-dimethoxybenzo[b]-fluoren-10-one and O4,O9-dimethylstealthin C (11-amino-5-hydroxy-4,9-dimethoxy-2-methylbenzo-[6]fluoren-10-one), methylated derivatives of potent radical scavengers produced by Streptomyces viridochromogenes, have been synthesized using Suzuki coupling as a key step.
- Koyama, Hiroya,Kamikawa, Tadao
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p. 203 - 209
(2007/10/03)
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- Total syntheses of O4,9-dimethyl stealthins A and C
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O4,9-dimethylstealthin A (11-amino-5-hydroxy-2-hydroxymethyl-4,9-dimethoxybenzo[b]fluoren-10-on e) and O4,9-dimethylstealthin C (11-amino-5-hydroxy-4,9-dimethoxy-2-methyl-benzo[b]fluoren-10-one), methylated derivatives of radical scavengers produced by Streptomyces viridochromogenes, were synthesized using the Suzuki coupling reactions as a key step.
- Koyama, Hiroya,Kamikawa, Tadao
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p. 3973 - 3976
(2007/10/03)
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- 3,3-diphenyl prop-2-yl amino acid derivatives and their use as tachykinin antagonists
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Compounds of formula (I), or a salt or prodrug thereof, wherein R1 represents H, C1-4 alkyl or CH2 COOH; R2 represents H or C1-4 alkyl, with the proviso that R1 and R2 are not both H; R3 and R4 each independently rely resent H, C1-, alkyl. C2-6 alkenyl C1-6 alkoxy, halo or trifluoromethyl; A1, A2, A3, and A4 each independently represent H, C1-6 alkyl, C1-6 alkenyl, C1-6 alkoxy, halo or trifluoromethyl; and A5 and A6 each independently represent H or C1-4 are tachykinin antagonists useful STR1
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- Nuclear versus Side-Chain Bromination of Methyl-Substituted Anisoles by N-Bromosuccinimide
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The reactions of methyl-substituted anisoles with N-bromosuccinimide in CCl4 are reported.In the absence of a catalyst and under irradiation, some of these substrates undergo nuclear bromination in competition with the well-known side-chain bromination.With 2-methylanisole and with 2,6-dimethylanisole, nuclear bromination is not observed, whereas with 3,5-dimethylanisole, nuclear bromination at the 4-position is the dominating reaction.Investigation of the reactivity of several other methyl-substituted anisoles revealed the following general trend: methyl-substituted anisoles are attacked at the position para to the methoxy group rather than at the side chain when (at least) two methyl groups are present at positions 3 and 5.When positions 2 and 6 are both occupied, nuclear bromination is retarded; in 2,6-dimethylanisole and 2,3,6-trimethylanisole, only side-chain bromination is observed.In contrast, in 2,3,5,6-tetramethylanisole, the 4-position is sufficiently reactive to be brominated, because the decrease in reactivity by the presence of two methyl groups at positions 2 and 6 is overruled by the two additional methyl groups at positions 3 and 5; as a result, both nuclear and side-chain bromination occur.The observed chemospecificity can be rationalized by a difference in mechanism: the side-chain bromination is radical reaction, while the nuclear bromination is an electrophilic aromatic substitution reaction, which is so far contrary to expectation, as irradiation had been expected to favor radical processes.
- Gruter, Gert-Jan M.,Akkerman, Otto S.,Bickelhaupt, Friedrich
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p. 4473 - 4481
(2007/10/02)
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- Benzoannelated Centropolyquinanes, 3. - Synthesis of Multiply Substituted Triptindans (9H,10H-4b,9a-(Benzenomethano)indenoindenes) with Substituents in their Molecular Cavity
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The synthesis of triptindans 13a-e substituted by methoxy and/or methyl groups in positions 2,4,5,7,13, and 15 has been achieved by acid-catalysed cyclodehydration of the corresponding 2,2-dibenzyl-1-indanones 12a-e using Amberlyst 15 and polyphosphoric acid, respectively.Total demethylation of 13a followed by selective deoxygenation of the resulting hexahydroxy compound 14 affords the 4,5,15-trihydroxytriptindan (17) (4, R = OH) bearing the three substituents in its molecular cavity.
- Kuck, Dietmar,Paisdor, Bernd,Gruetzmacher, Hans-Friedrich
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p. 589 - 596
(2007/10/02)
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