- Exploiting differences in solution vs solid-supported reactivity for the synthesis of sulfonic acid derivatives
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(matrix presented) Quantitative We describe a method herein for the protection of aryl and alkyl sulfonates during synthesis which employs commercially available Wang or MBOH resin, both of which terminate as benzyl alcohols, as both a protecting group and "traceless" linker. Given the known instability of benzylic sulfonate esters to nucleophilic displacement in solution, this linkage is surprisingly stable: no loss of either aryl or alkyl sulfonates is observed when the resin is exposed to a wide variety of organic bases and solvents at room temperature. Further elaboration of the resin-bound sulfonates via Suzuki coupling is also described.
- Hari, Anitha,Miller, Benjamin L.
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- Discovery of Potent, Selective, and Orally Active Carboxylic Acid Based Inhibitors of Matrix Metalloproteinase-13
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The matrix metalloproteinase enzyme MMP-13 plays a key role in the degradation of type II collagen in cartilage and bone in osteoarthritis (OA). An effective MMP-13 inhibitor would therefore be a novel disease modifying therapy for the treatment of arthritis. Our efforts have resulted in the discovery of a series of carboxylic acid inhibitors of MMP-13 that do not significantly inhibit the related MMP-1 (collagenase-1) or tumor necrosis factor-α (TNF-α) converting enzyme (TACE). It has previously been suggested (but not proven) that inhibition of the latter two enzymes could lead to side effects. A promising carboxylic acid lead 9 was identified and a convergent synthesis developed. This paper describes the optimization of 9 and the identification of a compound 24f for further development. Compound 24f is a subnanomolar inhibitor of MMP-13 (IC50 value 0.5 nM and Ki of 0.19 nM) having no activity against MMP-1 or TACE (IC50 of >10000 nM). Furthermore, in a rat model of MMP-13-induced cartilage degradation, 24f significantly reduced proteoglycan release following oral dosing at 30 mg/kg (75% inhibition, p 0.05) and at 10 mg/kg (40% inhibition, p 0.05).
- Monovich, Lauren G.,Tommasi, Ruben A.,Fujimoto, Roger A.,Blancuzzi, Vincent,Clark, Kirk,Cornell, Wendy D.,Doti, Robert,Doughty, John,Fang, James,Farley, David,Fitt, John,Ganu, Vishwas,Goldberg, Ronald,Goldstein, Robert,Lavoie, Stacey,Kulathila, Raviraj,Macchia, William,Parker, David T.,Melton, Richard,O'Byrne, Elizabeth,Pastor, Gary,Pellas, Theodore,Quadros, Elizabeth,Reel, Noela,Roland, Dennis M.,Sakane, Yumi,Singh, Hem,Skiles, Jerry,Somers, Joseph,Toscano, Karen,Wigg, Andrew,Zhou, Siyuan,Zhu, Lijuan,Shieh, Wen-Chung,Xue, Song,McQuire, Leslie W.
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supporting information; experimental part
p. 3523 - 3538
(2010/03/30)
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- Structural Characterization of Crystalline Ternary Inclusion Compounds at the Air-Water Interface
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Crystalline ternary inclusion monolayers consisting of a two-dimensional hydrogen-bonded host network of guanidinium (G) ions and organosulfonate (S) amphiphiles, and biphenylalkane guests, can be generated at the air-water interface through synergistic structural enforcement by hydrogen bonding and host-guest packing. Surface pressure-area isotherms of the 4′ -hexadecylbiphenyl-4-sulfonate (C16BPS) amphiphile in the presence of G, with or without guest, are characterized by lift-off molecular areas expected for the GS sheet based on single-crystal X-ray structures of homologous bulk crystals. Intercalation of biphenylalkane guests (4-CnH 2n+1-C6H4-C6H5, n = 1, 4, 6, 10, 16; denoted CnBP) between organosulfonate hydrophobes, which define pocketlike cavities in the GS monolayer host, afford ternary inclusion monolayers with a 1:1 host-guest stoichiometry. These inclusion monolayers are less compressible than the guest-free host, consistent with dense packing of the biphenylalkane moieties of the host and the biphenylalkane guests. The inclusion monolayers are distinguished from the amorphous guest-free host and from selected guanidinium-free mixed monolayers by structural characterization with grazing-angle incidence X-ray diffraction (GIXD). The GIXD data for the ternary (G)C16BPS:C16BP and (G)C16BPS:C6BP inclusion monolayers obtained upon compression are consistent with a rectangular unit cell. The dimensions of these unit cells and refinement of the GIXD data suggest a "rotated shifted ribbon" GS hydrogen-bonding motif similar to that observed in some bulk GS crystals, including (G) (ethylbiphenylsulfonate). GIXD reveals that (G)C16BPS:C16BP and (G)C16BPS:C6BP are more crystalline than the corresponding guanidinium-free mixed monolayers. The (G)C16BPS:C6BP inclusion monolayer is stable upon compression, even though the alkyl-alkyl host-guest interactions are reduced due to the shorter hexyl substituents of the guest, demonstrating an important reinforcing role for the hydrogen-bonded GS sheet. The structure of a C16BPS: tetracosane (C24) mixed monolayer is independent of G; the unit cell symmetry and dimensions suggest a structure governed by alkyl-alkane interactions that prohibit formation of a GS network. These results illustrate that the existence of ternary inclusion monolayers with an intact GS network requires guest molecules that are structurally homologous with the hydrophobes of the host, in this case biphenylalkanes. The observation of these inclusion compounds suggests an approach for introducing functional nonamphiphilic molecules to an air-water interface through inclusion in a well-defined host.
- Plaut, David J.,Martin, Stephen M.,Kjaer, Kristian,Weygand, Markus J.,Lahav, Meir,Leiserowitz, Leslie,Weissbuch, Isabelle,Ward, Michael D.
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p. 15922 - 15934
(2007/10/03)
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