- Lipase-catalyzed desymmetrization of meso-1,2-diaryl-1,2-diaminoethanes
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The synthesis and enzyme-catalyzed desymmetrization of meso-1,2-diaryl-1,2- diaminoethanes have been investigated. A family of aromatic meso-1,2-diamines, containing different substitution patterns in the aromatic ring, was first prepared and then desymmetrized enantioselectively using lipases as biocatalysts. Selective alkoxycarbonylation of one of the amino groups was achieved using allyl carbonates, isolating the corresponding allyl monocarbamates with moderate to high enantiomeric excess at 45 C. Candida antarctica lipase types A (CAL-A) and B (CAL-B) displayed the best activities and stereopreferences, with a dramatic influence being observed depending on the diamine structure. Non substituted and para-substituted aryldiamines led to the formation of allyl carbamates with good enantiomeric excess, using CAL-A for the less hindered substrates and CAL-B for the more hindered ones. On the other hand meta- and ortho-derivatives afforded low or negligible conversions and selectivities, respectively.
- Mendez-Sanchez, Daniel,Rios-Lombardia, Nicolas,Garcia-Granda, Santiago,Montejo-Bernardo, Jose,Fernandez-Gonzalez, Alfonso,Gotor, Vicente,Gotor-Fernandez, Vicente
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p. 381 - 386
(2014/04/03)
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- Synthesis and evaluation of an imidazole derivative-fluorescein conjugate
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The murine double minute (MDM2) oncogene a negative regulator of protein 53 (p53) tumor suppressor, is found overexpressed in many different types of cancer and the interaction between MDM2 and p53 has become the target of intensive research. MDM2 inhibitors represent a promising class of p53 activating compounds that may be effective in cancer treatment and diagnostic imaging. Nutlins, a family of cis-imidazoline analogues and small-molecule MDM2 antagonists, have the potential use in cancer therapies. We have synthesized an imidazole derivative (Nutlin-Glycine) conjugated to the commonly used fluorophore, 6-carboxyfluorescein (FAM) and evaluated its possible use as an imaging agent. Cellular uptake studies demonstrated that the fluorescence intensity in human osteosarcoma (SJSA-1) and colon carcinoma (HCT116) cells were significantly increased with the treatment of Nutlin-Glycine-FAM when compared with FAM (control). Blocking studies also confirmed that our imidazole-fluorescein conjugate may be a good candidate for imaging tumors, suggesting the need for further in vivo evaluation by positron emission tomography.
- Ghosh, Pradip,Zhang, Jiawei,Shi, Zheng-Zheng,Li, King
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p. 2418 - 2425
(2013/05/22)
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