- Synthesis of macrocyclic and medium-sized ring thiolactonesviathe ring expansion of lactams
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A side chain insertion method for the ring expansion of lactams into macrocyclic thiolactones is reported, that can also be incorporated into Successive Ring Expansion (SuRE) sequences. The reactions are less thermodynamically favourable than the analogous lactam- and lactone-forming ring expansion processes (with this notion supported by DFT data), but nonetheless, three complementary protecting group strategies have been developed to enable this challenging transformation to be achieved.
- Palate, Kleopas Y.,Epton, Ryan G.,Whitwood, Adrian C.,Lynam, Jason M.,Unsworth, William P.
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supporting information
p. 1404 - 1411
(2021/02/27)
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- Synthesis and biological evaluation of santacruzamate A analogues for anti-proliferative and immunomodulatory activity
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Santacruzamate A (SCA) is a natural product isolated from a Panamanian marine cyanobacterium, previously reported to have potent and selective histone deacetylase (HDAC) activity. To optimize the enzymatic and cellular activity, 40 SCA analogues were synthesized in a systematic exploration of the zinc-binding group (ZBG), cap terminus, and linker region. Two cap group analogues inhibited proliferation of MCF-7 breast cancer cells, with analogous increased degranulation of cytotoxic T cells (CTLs), while one cap group analogue reduced CTL degranulation, indicative of suppression of the immune response. Additional testing of these analogues resulted in reevaluation of the previously reported SCA mechanism of action. These analogues and the resulting structure–activity relationships will be of interest for future studies on cell proliferation and immune modulation.
- Gromek, Samantha M.,deMayo, James A.,Maxwell, Andrew T.,West, Ashley M.,Pavlik, Christopher M.,Zhao, Ziyan,Li, Jin,Wiemer, Andrew J.,Zweifach, Adam,Balunas, Marcy J.
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supporting information
p. 5183 - 5196
(2016/10/24)
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- Synthesis, CoMFA analysis, and receptor docking of 3,5-diacyl-2,4- dialkylpyridine derivatives as selective A3 adenosine receptor antagonists
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3,5-Diacyl-2,4-dialkyl-6-phenylpyridine derivatives have been found to be selective antagonists at both human and rat A3 adenosine receptors (Li et al. J. Med. Chem. 1998, 41, 3186-3201). In the present study, ring- constrained, fluoro, hydroxy, and other derivatives in this series have been synthesized and tested for affinity at adenosine receptors in radioligand binding assays. K(i) values at recombinant human and rat A3 adenosine receptors were determined using [125I]AB-MECA (N6-(4-amino-3-iodobenzyl)- 5'-N-methylcarbamoyladenosine). Selectivity for A3 adenosine receptors was determined vs radioligand binding at rat brain A1 and A(2A) receptors, and structure-activity relationships at various positions of the pyridine ring (the 3- and 5-acyl substituents and the 2- and 4-alkyl substituents) were probed. At the 5-position inclusion of a β-fluoroethyl (7) or a γ- fluoropropyl ester (26) was favorable for human A3 receptor affinity, resulting in K(i) values of 4.2 and 9.7 nM, respectively, while the pentafluoropropyl analogue was clearly less potent at human A3 receptors. At the 2-, 3-, and 4-positions, fluoro or hydroxy substitution failed to enhance potency and selectivity at human A3 receptors. Several analogues were nearly equipotent at rat and human A3 receptors. To further define the pharmacophore conformationally, a lactam, a lactone, and thiolactones were tested in adenosine receptor binding. The most potent analogue in this group was compound 34, in which a thiolactone was formed between 3- and 4-positions and which had a K(i) value of 248 nM at human A3 receptors. Using affinity data and a general pharmacophore model for A3 adenosine receptor antagonists recently proposed, we applied comparative molecular field analysis (CoMFA) to obtain a three dimensional quantitative structure-activity relationship for pyridine derivatives, having good predictability (r2(pred) = 0.873) for compounds in the test set. A rhodopsin-based model of the human As receptor was built, and the pyridine reference ligand 2,3,4,5-tetraethyl-6-phenyl- pyridine-3-thiocarboxylate-5-carboxylate (MRS 1476) was docked in the putative ligand binding site. Interactions between receptor transmembrane domains and the steric and the electrostatic contour plots obtained from the CoMFA analysis were analyzed.
- Li, An-Hu,Moro, Stefano,Forsyth, Nancy,Melman, Neli,Ji, Xiao-Duo,Jacobson, Kenneth A.
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p. 706 - 721
(2007/10/03)
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- Ethanethioates and mercaptoamides and use thereof as analgesic and enkephalinase inhibitory compounds
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Novel analgesic and enkephalinase inhibiting compositions comprising an analgesically and enkephalinase inhibitory effective amount of at least one compound selected from the group consisting of a compound of the formula STR1 wherein R1 is selected from the group consisting of hydrogen and acetyl, n is 1 or 2 and when n is 1, R2 is selected from the group consisting of phenyl, p-chlorophenyl, m-trifluoromethylphenyl and thiazolyl and when n is 2, R2 is selected from the group consisting of phenyl and p-chlorophenyl and their salts with non-toxic, pharmaceutically acceptable acids and bases and an inert pharmaceutical carrier and novel method of relieving pain and inhibiting enkephalinase activity in warm-blooded animals and novel amides.
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