Friedel–Crafts hydroxyalkylation of indoles mediated by trimethylsilyl trifluoromethanesulfonate

Indoles and N-alkylindoles undergo Friedel–Crafts addition to aldehydes in the presence of trimethylsilyl trifluoromethanesulfonate and a trialkylamine to produce 3-(1- silyloxyalkyl)indoles. Neutralization of the reaction mixture with pyridine followed by deprotection under basic conditions with tetrabutylammonium fluoride provides the 1:1 adduct as the free alcohol. This method prevents spontaneous conversion of the desired products to the thermodynamically favored bisindolyl(aryl)methanes, a process typically observed when indoles are reacted with aldehydes under acidic conditions

Friedel–Crafts addition of indoles to nitrones promoted by trimethylsilyl trifluoromethanesulfonate

N-alkylindoles undergo Friedel–Crafts addition to aryl and secondary alkyl nitrones in the presence of trimethylsilyl trifluoromethanesulfonate and a trialkylamine to produce 3-(1- (silyloxyamino)alkyl)indoles. Spontaneous conversion to the bisindolyl(aryl)methanes, which is thermodynamically favored for nitrones derived from aromatic aldehydes, is suppressed under the reaction conditions. The silyloxyamino group can be deprotected with tetrabutylammonium fluoride to yield the hydroxylamine

Investigating the Effect of Sugar Alternatives on U87 Human Derived Glioblastoma Cell Survival and Proliferation

The Ketogenic Diet (KD) is currently being investigated as an adjuvant cancer therapy. This high-fat, low-carbohydrate, moderate-protein diet is thought to work in part by reducing glucose availability for cancer cells, a key substrate in their growth and proliferation. With a growing number of clinical trials seeking to understand the effects of KDs on cancer patients, it is important to study potential confounding factors that may complicate KD use in a clinical setting. Sugar Alternatives (SA) are commonly used in KD recipes wishing to mimic sugar-based products, but little is known about their individual effects on cancer growth and proliferation. Recent research suggests erythritol may enhance growth at low, near-physiological concentrations, but may elicit an inhibitory effect at high concentrations. U87 human glioblastoma cells were seeded at 15,000 per well and cultured for 7 days in 2mL of 5mM glucose, 5mM glutamine Dulbecco\u27s Modified Eagle\u27s Medium with or without 25mM of saccharin, sucralose, aspartame, erythritol, stevia, or allulose added as treatment. Each treatment had an n=4. 0, 5, and 25mM glucose and 5mM glutamine containing DMEM served as controls, with an n=6. Cell survival and proliferation were assessed via live/dead staining and hemocytometry on day 8. Pilot study limitations led to inconclusive data, however, protocol optimization including increasing seeding number, addressing aspartame solubility issues, and addressing poly-D-lysine issues is ongoing

Investigating the Effect of Sugar Alternatives on U87 Human Derived Glioblastoma Cell Survival and Proliferation

The Ketogenic Diet (KD) is currently being investigated as an adjuvant cancer therapy. This high-fat, low-carbohydrate, moderate-protein diet is thought to work in part by reducing glucose availability for cancer cells, a key substrate in their growth and proliferation. With a growing number of clinical trials seeking to understand the effects of KDs on cancer patients, it is important to study potential confounding factors that may complicate KD use in a clinical setting. Sugar Alternatives (SA) are commonly used in KD recipes wishing to mimic sugar-based products, but little is known about their individual effects on cancer growth and proliferation. Recent research suggests erythritol may enhance growth at low, near-physiological concentrations, but may elicit an inhibitory effect at high concentrations. U87 human glioblastoma cells were seeded at 15,000 per well and cultured for 7 days in 2mL of 5mM glucose, 5mM glutamine Dulbecco\u27s Modified Eagle\u27s Medium with or without 25mM of saccharin, sucralose, aspartame, erythritol, stevia, or allulose added as treatment. Each treatment had an n=4. 0, 5, and 25mM glucose and 5mM glutamine containing DMEM served as controls, with an n=6. Cell survival and proliferation were assessed via live/dead staining and hemocytometry on day 8. Pilot study limitations led to inconclusive data, however, protocol optimization including increasing seeding number, addressing aspartame solubility issues, and addressing poly-D-lysine issues is ongoing

Designing a Planar Chiral Rhodium Indenyl Catalyst for Regio- and Enantioselective Allylic C-H Amidation

© 2020 American Chemical Society Chiral variants of group IX Cp and Cp* catalysts are well established and catalyze a broad range of reactions with high levels of enantioselectivity. Enantiocontrol in these systems results from ligand design that focuses on appropriate steric blocking. Herein we report the development of a new planar chiral indenyl rhodium complex for enantioselective C-H functionalization catalysis. The ligand design is based on establishing electronic asymmetry in the catalyst, to control enantioselectivity during the reactions. The complex is easily synthesized from commercially available starting materials and is capable of catalyzing the asymmetric allylic C-H amidation of unactivated olefins, delivering a wide range of high-value enantioenriched allylic amide products in good yields with excellent regio- and enantioselectivity. Computational studies suggest that C-H cleavage is rate- and enantio-determining, while reductive C-N coupling from the Rh-v-nitrenoid intermediate is regio-determining11Nsciescopu

Behavioral thermoregulation and slowed migration by adult fall Chinook salmon in response to high Columbia River water temperatures

The relationships between lower Columbia River water temperatures and migration rates, temporary tributary use, and run timing of adult fall Chinook salmon Oncorhynchus tshawytscha were studied using historical counts at dams and recently collected radiotelemetry data. The results from more than 2,100 upriver bright fall Chinook salmon radio-tagged over 6 years (1998, 2000-2004) showed that mean and median migration rates through the lower Columbia River slowed significantly when water temperatures were above about 20 degrees C. Slowed migration was strongly associated with temporary use of tributaries, which averaged 2-7 degrees C cooler than the main stem. The proportion of radio-tagged salmon using tributaries increased exponentially as Columbia River temperatures rose within the year, and use was highest in the warmest years. The historical passage data showed significant shifts in fall Chinook salmon run timing distributions concomitant with Columbia River warming and consistent with increasing use of thermal refugia. Collectively, these observations suggest that Columbia River fall Chinook salmon predictably alter their migration behaviors in response to elevated temperatures. Coolwater tributaries appear to represent critical habitat areas in warm years, and we recommend that both main-stem thermal characteristics and areas of refuge be considered when establishing regulations to protect summer and fall migrants