- An efficient synthesis of l-3,4,5-trioxygenated phenylalanine compounds from l-tyrosine
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A new strategy for the synthesis of l-3,4,5-trioxygenated phenylalanine derivatives from l-tyrosine is developed for the first time. The approach, featuring the transformation of aryl diiodide to bis-phenol via a one-pot procedure including lithiation, boronation, and oxidation, is highly practical. By this robust protocol, N-protected l-3,5-bis(tert-butyldimethylsilyloxy)-4- methoxy-phenylalanine and l-3,4,5-trimethoxy-phenylalanine derivatives were obtained from l-tyrosine in 9 steps with 36-40% overall yields.
- Chen, Ruijiao,Liu, Hao,Liu, Xiubing,Chen, Xiaochuan
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p. 3565 - 3570
(2013/04/24)
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- Characterization of thyroid hormone receptor α (TRα)-specific analogs with varying inner- and outer-ring substituents
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Analogs of the TRα-specific thyromimetic CO23 were synthesized and analyzed in vitro using competitive binding and transactivation assays. Like CO23, all analogs bind to both thyroid hormone receptor subtypes with about the same affinity; however, modification of CO23 by derivatization of the 3′ position of the outer-ring or replacement of the inner-ring iodides with bromides attenuates binding. Despite lacking a preference in binding to TRα, all analogs display TRα-specificity in transactivation assays using U2OS and HeLa cells. At best, several agonists exhibit an approximately 6-12-fold preference in transactivation when tested with TRα in HeLa cells. One analog, CO24, showed in vivo TRα-specific action in a tadpole metamorphosis assay.
- Ocasio, Cory A.,Scanlan, Thomas S.
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p. 762 - 770
(2008/09/17)
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- The synthesis, distribution, and anti-hepatic cancer activity of YSL
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(I) HCl/CH3OH; (II) DCC/HOBt/NMM with corresponding carboxyl component; (III) HCl/CH3CO2C2H5 (6 mol/L); (IV) NaOH/H2O/CH3OH; (V) 3H2 and 10% Pd/C. YSL was prepared stepwise from C terminal to N terminal with the side chain un-protective amino acids, Boc-Leu-OMe, Boc-Ser-OH, and Boc-Tyr-OH, as the starting materials in 39.5% total yield (31.2 g/per batch). With the side chain un-protective Boc-(3,5-dibromo)-Tyr-OH and HClA·Ser-Leu-OMe as the starting materials (3,5-3H-Tyr)-Ser-Leu-OH was obtained in 29% yield. The determination of radioactive quantity in the urine and feces indicated that even after the administration for 130 h only 8.4% (5.35% in urine and 3.05% in feces) of total radioactive quantity from the metabolite of [3,5-3H-Tyr]-Ser-Leu-OH were monitored. The distribution study revealed the relative accumulation level of the individual tissue was arranged in the sequence of spleen > liver > kidney > lung > heart > muscle > brain. Selecting hepatic cancer as the target YSL significantly increased the survival time of H22 tumor cells implanted mice.
- Ding, Wenfeng,Zhang, Jiali,Yao, Zhi,Lu, Rong,Wu, Dezhu,Li, Ginfu,Shen, Zilong,Sun, Yingji,Lin, Gang,Wang, Chao,Zhao, Ming,Peng, Shiqi
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p. 4989 - 4994
(2007/10/03)
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