Romen Carrillo

Ascorbic Acid as an Initiator for the Direct CH Arylation of (Hetero)arenes with Anilines Nitrosated In Situ

Ascorbic acid (vitamin C) has been used as a radical initiator in a metal-free direct C-H arylation of (hetero)arenes. Starting from an aniline, the corresponding arenediazonium ion is generated in situ and immediately reduced by vitamin C to an aryl radical that undergoes a homolytic aromatic substitution with a (hetero)arene. Notably, neither heating nor irradiation is required. This procedure is mild, operationally simple, and constitutes a greener approach to arylation.

Correlation between Conformational Equilibria of Free Host and Guest Binding Affinity in Non-preorganized Receptors

Positive cooperativity between host conformational equilibria and guest binding has been widely reported in protein receptors. However, reported examples of this kind of cooperativity in synthetic hosts are scarce and largely serendipitous, among other things because it is hard to envision systems which display this kind of cooperativity. In order to shed some light on the correlation between conformational equilibria of free host and guest binding, selected structural modifications have been performed over a family of nonpreorganized hosts in order to induce conformational changes and to analyze their effect on the binding affinity. The conformational effect was evaluated by a theoretical conformational search and correlated with the ability of the receptors. All data suggest that those receptors that display the best association constants are able to sample folded conformations analogous to the conformational requirements for the binding of the guests. On the contrary, for those receptors where folded conformers are scarce, then the association constant and enantioselectivity clearly drop.

Sustainable oxidations with air mediated by gallic acid: potential applicability in the reutilization of grape pomace

Gallic acid converts atmospheric oxygen into hydrogen peroxide, which is able to oxidize arylboronic acids as a proof of concept of sustainable oxidations. Moreover, tannic acid and grape pomace extract are also able to perform oxidations with air. Therefore this work unleashes an alternative method for reutilization and valorization of bio-wastes rich in tannins.

Mild-Base-Promoted Arylation of (Hetero)Arenes with Anilines

Transition metal-free radical arylation of heteroarenes is achieved at room temperature by simply adding aqueous sodium carbonate to a solution of the corresponding heteroarene and arenediazonium salt, which can even be formed in situ. Such an easy, inexpensive and mild methodology has been optimized and applied to the expeditious modification of interesting molecular cores like naphthylimide or bisthienylcyclopentenes.

Fluorescent β-Blockers as Tools to Study Presynaptic Mechanisms of Neurosecretion

Several, if not all adrenergic β-blockers (β-Bs), accumulate progressively inside secretory vesicles in a time- and concentration-dependent manner, and could be considered to be false neurotransmitters. This transmitter effect is most likely unrelated to their ability to block adrenergic receptors, but it could explain the delay in lowering arterial pressure in hypertensive patients. We have developed a new drug to monitor the accumulation of β-Bs inside living cells, RCTM-3, which fluoresces in the visible spectrum. Here we describe the procedure to synthesize this new compound, as well as its fluorescent properties, pharmacological profile and its accumulation inside the secretory vesicles of PC12 cells.

Synthesis of New Benzocyclotrimer Analogues: New Receptors for Tetramethylammonium Ion Recognition.

Using a [2 + 2 + 2] cycloaddition/Mitsunobu reaction sequence, a convenient synthesis to access new benzocyclotrimer analogues has been developed. The new receptors have the geometry and functionality capable of recognizing the tetramethylammonium ion in the gas phase and in solution.