- Synthesis and characterization of BODIPY-α-tocopherol: A fluorescent form of vitamin e
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Fluorescent nitrobenzoxadiazole analogues of α-tocopherol (NBD-α-Tocs; λex = 468 nm, λem = 527 nm) have been made previously to aid study of the intracellular location and transfer of vitamin E. However, these analogues are susceptible to photobleaching while under illumination for confocal microscopy as well as in in vitro FRET transfer assays. Here we report the synthesis of three fluorescent analogues of α-tocopherol incorporating the more robust dipyrrometheneboron difluoride (BODIPY) fluorophore. A BODIPY-linked chromanol should have no intervening polar functional groups that might interfere with binding to the hydrophobic binding site of the tocopherol transfer protein (α-TTP). A key step in bringing the two ring systems together was a metathesis reaction of vinyl chromanol and an alkenyl BODIPY. An o-tolyl containing second generation Grubbs catalyst was identified as the best catalyst for effecting the metathesis without detectable alkene isomerization, which when it occurred produced a mixture of chain lengths in the alkyl linker. C8-BODIPY-α-Toc 10c (λex = 507 nm, λem = 511 nm, ε507 = 83,000 M-1 cm-1) having an eight-carbon chain between the chromanol and fluorophore, had the highest affinity for α-TTP (Kd = 94 ' 3 nM) and bound specifically as it could not be displaced with cholesterol.
- West, Ryan,Panagabko, Candace,Atkinson, Jeffrey
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- Lessons in Strain and Stability: Enantioselective Synthesis of (+)-[5]-Ladderanoic Acid
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The synthesis of structurally complex and highly strained natural products provides unique challenges and unexpected opportunities for the development of new reactions and strategies. Herein, the synthesis of (+)-[5]-ladderanoic acid is reported. En route to the target, unusual and unexpected strain release driven transformations were uncovered. This occurrence required a drastic revision of the synthetic design that ultimately led to the development of a novel stepwise cyclobutane assembly by an allylboration/Zweifel olefination sequence.
- Hancock, Erin N.,Kuker, Erin L.,Tantillo, Dean J.,Brown, M. Kevin
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supporting information
p. 436 - 441
(2019/11/25)
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- Novel aerobic oxidation of primary sulfones to carboxylic acids
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Primary alkyl aryl sulfones are converted to the corresponding carboxylic acids in fair to excellent yield through double deprotonation and exposure to atmospheric oxygen. The methodology allows for the convenient synthesis of 13C labeled carboxylic acids.
- Bonaparte, Amy C.,Betush, Matthew P.,Panseri, Bettina M.,Mastarone, Daniel J.,Murphy, Ryan K.,Murphree, S. Shaun
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p. 1447 - 1449
(2011/05/08)
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- Shape and aggregating tendency. The aggregating behavior of eight esters of eight-carbon carboxylic acids
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The aggregating tendencies of eight p-nitrophenyl esters of eight-carbon carboxylic acids (1-8) and two O-octyl phosphonates (10, 11) have been evaluated by measuring their critical aggregate concentrations (CAgG's). Results show that (1) branching reduce
- Jiang, Xi-Kui,Ji, Guo-Zhen,Tu, Bo,Zhang, Xin-Yu,Shi, Ji-Liang,Chen, Xin
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p. 12679 - 12682
(2007/10/03)
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