23030-65-1Relevant articles and documents
ONO-pincer ruthenium complex-bound norvaline for efficient catalytic oxidation of methoxybenzenes with hydrogen peroxide
Yoshida, Ryota,Isozaki, Katsuhiro,Yokoi, Tomoya,Yasuda, Nobuhiro,Sadakane, Koichiro,Iwamoto, Takahiro,Takaya, Hikaru,Nakamura, Masaharu
supporting information, p. 7468 - 7479 (2016/08/16)
The enhanced catalytic activity of ruthenium complex-bound norvaline Boc-l-[Ru]Nva-OMe 1, in which the ONO-pincer ruthenium complex Ru(pydc)(terpy) 2 is tethered to the α-side chain of norvaline, has been demonstrated for the oxidation of methoxybenzenes to p-benzoquinones with a wide scope of substrates and unique chemoselectivity.
Total synthesis of graphislactones A, C, D, and H, of ulocladol, and of the originally proposed and revised structures of graphislactones e and F
Altemoeller, Martina,Gehring, Timo,Cudaj, Judith,Podlech, Joachim,Goesmann, Helmut,Feldmann, Claus,Rothenberger, Alexander
scheme or table, p. 2130 - 2140 (2009/09/29)
Graphislactones A-H and the structurally related ulocladol are highly oxygenated resorcylic lactones produced by lichens and fungi. We present total syntheses of graphislactones A, C-F, H and of ulocladol. Graphislactones E, F, and H were synthesized for the first time. The spectra of graphislactones E and F synthesized as the originally proposed structures were not in agreement with published data. Consequently, revised structures for these compounds are proposed, whose correctness is unambiguously proven by total synthesis and comparison of the spectroscopic data. Key steps in all syntheses are Suzuki couplings for the construction of the central biaryl bond and Dakin reactions to supply further hydroxy groups required in these highly oxygenated substrates. Graphislactones A, C, and H, acylated graphislac- tone D and ulocladol were prepared in 8-11 steps with 7-20% yield starting with purchasable compounds, where the longest linear sequence consists of 5-9 steps. The syntheses are thus significantly shorter than the previously published syntheses of graphislactones A-D and of ulocladol. Graphis- lactones E and F were synthesized in 8 steps, where the longest linear sequences consist of 6 and 5 steps, respectively. They were isolated as the respective acetylated compounds with 25 and 10% yield.
Analogs of 3-hydroxy-1H-1-benzazepine-2,5-dione: Structure-activity relationship at N-methyl-D-aspartate receptor glycine sites
Guzikowski, Anthony P.,Cai, Sui Xiong,Espitia, Stephen A.,Hawkinson, Jon E.,Huettner, James E.,Nogales, Daniel F.,Tran, Minhtam,Woodward, Richard M.,Weber, Eckard,Keana, John F. W.
, p. 4643 - 4653 (2007/10/03)
A series of aromatic and azepine ring-modified analogs of 3-hydroxy-1H- 1-benzazepine-2,5-dione (HBAD) were synthesized and evaluated as antagonists at NMDA receptor glycine sites. Aromatic ring-modified HBADs were generally prepared via a Schmidt reaction with substituted 2-methoxynaphthalene-1,4- diones followed by demethylation. Electrophilic aromatic substitution of benzazepine 3-methyl ethers gave 7-substituted analogs. The preparation of multiply substituted 2-methoxynaphthalene-1,4-diones was effected via Diels- Alder methodology utilizing substituted butadienes with 2- methoxybenzoquinones followed by aromatization. Structural modifications, such as elimination of the aromatic ring, removal of the 3-hydroxyl group, and transfer of the hydroxyl group from C-3 to C-4, were also studied. An initial evaluation of NMDA antagonism was performed using a [3H]MK801 binding assay. HBADs demonstrating NMDA antagonist activity as indicated by inhibition of [3H]MK801 binding were further evaluated employing a [3H]- 5,7-dichlorokynurenic acid (DCKA) glycine site binding assay. Selected HBADs were characterized for functional antagonism of NMDA and AMPA receptors using electrophysiological assays in Xenopus oocytes and cultured rat cortical neurons. Antagonist potency of HBADs showed good correlation between the different assay systems. HBADs substituted at the 8-position possessed the highest potency with the 8-methyl (5), 8-chloro (6), and 8-bromo (7) analogs being the most active. For HBAD 6, the IC50 in [3H]-DCKA binding assays was 0.013 μM and the K(b) values for antagonism of NMDA receptors in oocytes (NR1a/2C) and cortical neurons were 0.026 and 0.048 μM, respectively. HBADs also antagonized AMPA-preferring non-NMDA receptors expressed in oocytes but at a lower potency than corresponding inhibition of NMDA receptors. HBADs demonstrating a high potency for NMDA glycine sites showed the highest steady-state selectivity index relative to AMPA receptors. Substitution at the 6-, 7-, and 9-positions generally reduced or eliminated glycine site affinity. Moving the hydroxyl group from C-3 to C-4 reduced receptor affinity, and potency was eliminated by the removal of the aromatic ring or the hydroxyl group. These data indicate that the HBAD series has specific structural requirements for high receptor affinity. With the exception of substitution at C-8, modified HBADs generally have a lower affinity at NMDA receptor glycine sites than the parent compound 3. Mouse maximum electroshock-induced seizure studies show that the three HBADs selected for testing have in vivo potency with the 6,8-dimethyl analog (52) being the most potent (ED50 = 3.9 mg/kg, iv).
