Vesicles and other bilayered membranous structures can self-assemble from single hydrocarbon chain amphiphiles. Their formation and stability are highly dependent upon experimental conditions such as ionic strength, pH and temperature. The addition of divalent cations, for example, often results in the disruption of vesicles made of a single fatty acid species through amphiphile precipitation. However, membranes composed of amphiphile mixtures have been shown to be more resistant to low millimolar concentrations of divalent cations at room temperature. In this report, several mixtures of amphiphiles are examined for their propensity to self-assemble into membranous vesicular structures under extreme environmental conditions of low pH, high ionic strengths and temperatures. In particular, mixtures of decylamine with polar co-surfactants were found to efficiently form membranes under these conditions far away from those normally supporting vesicle formation. We further examined decanoic acid/decylamine mixtures in detail: at pH 2 in low ionic strength solutions, the amphiphiles formed oily or crystalline structures, however the introduction of salts or/and strong acids in conjunction with high temperature induced a stable vesiculation. Thus, extreme environments, such as volcanic or vent environments, whose environmental conditions are known to support high chemical reactivity, could have harbored and most significantly promoted the formation of simple organic compartments that preceded cells.
Herein we disclosed an unprecedented photochemically driven nickel-catalyzed carboxylative Buchwald-Hartwig amination to access a wide range of aryl carbamate derivatives. This reaction is performed under mild condition of temperature and atmospheric pressure of CO 2 starting from commercially available (hetero)aryl iodides/bromides derivatives and alkyl amines preventing the formation of hazardous and/or toxic waste. Moreover, preliminary mechanistic investigations including stochiometric experiments as well as DFT calculations allow us to shed light on the reaction mechanism.
Polysubstituted tetrahydroquinolines were obtained in moderate to high yields (28% to 92%) and enantiomeric ratios (er 89:11 to 99:1) by a three‐component Povarov reaction using a chiral phosphoric acid catalyst. Significantly, post‐Povarov functional group interconversions allowed a rapid access to a library of 36 enantioenriched 4‐aminotetrahydroquinoline derivatives featuring five points of diversity. Selected analogs were assayed for their ability to function as glucagon‐like peptide‐1 (GLP‐1) secretagogues.
Herein we disclosed an unprecedented photochemically driven nickel-catalyzed carboxylative Buchwald Hartwig amination to access a wide range of aryl carbamate derivatives. This reaction is performed under mild condition of temperature and atmospheric pressure of CO2 starting from commercially available (hetero)aryl iodides/bromides derivatives and alkyl amines preventing the formation of hazardous and/or toxic waste. Moreover, preliminary mechanistic investigation including stochiometric experiments as well as DFT calculations allows us to shed the light on the reaction mechanism.
The title compound, C16H18N2O, was synthesized via reaction of (1S,4R)-1,2,3,4-tetrahydro-1,11,11-trimethyl-1,4-methanophenazine with 3-chloroperbenzoic acid in dichloromethane. The absolute configuration for the product was assigned based on the stereochemistry of the camphorquinone reactant.
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