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Blumenol A (1), blumenol B (2) and loliolide (3), together with the ubiquitous β-sitosterol, α-amyrin and β-amyrin, were isolated from the organic extract of the leaves of Heliotropium angiospermum. Structural elucidation of the metabolites was carried out by analysis of…

An efficient diastereoselective Michael addition of the commercial potassium O-ethyl dithiocarbonate to Baylis-Hillman adducts in the presence of 9-BBN (9-borabicyclo[3.3.1]nonane) as a Lewis acid is reported. 9-BBN both protected the hydroxyl group and activated the carbonyl of the Michael acceptor.

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A mild and efficient method for the mono-oxidation of diols to the corresponding hydroxyaldehydes with trialkylammonium fluorochromates(VI), R3NH[CrO3F] (R= CH3, C2H5 C3H7 and C4H9), in solution at room temperature, and in solution under microwave radiation, is reported. The easy procedure,…

Disperse yellow 54 (DY54) was adsorbed onto two biopolymers, alginic acid and xanthan. The adsorption isotherms for the biopolymer-DY54 system showed that the adsorption mechanism can best be described by Zimm-Bragg theory. UV-Visible, FT-IR and MicroRaman studies suggest that DY54…

In this paper we describe the design and use of a sample holder for measurements of colour centers in elpasolite crystals irradiated at liquid nitrogen temperatures and measured at the same temperature by electron paramagnetic resonance spectroscopy.

This paper postulates that self-employment activities in Mexico City are subject to network contagion. This implies that entry-exit in self-employment is affected by other agents' decisions because individuals obtain increasing returns from conformity. In particular, it is claimed that physical…