Electron-rich aromatic compounds such as 2-naphthol give a faster and asymmetric 1-aminoalkylation with high yields when treated with (R)-1-phenylethylamine and aromatic aldehydes in solvent-free conditions. An asymmetric transformation of a second kind, probably induced by the preferential crystallization of one diastereomer, affords the straightforward and stereoselective synthesis of aminoalkylnaphthols. Mechanisms predictable for this asymmetric reaction are reported. The absolute configurations and the conformations of the unknown aminonaphthols are widely ascertained.

No abstract

The reduction of enantiopure β-enamino esters 1 with sodium triacetoxyborohydride in acetic acid is described. This occurs with good diastereo- and enantioselectivity to yield β-amino esters 2 and 3 (after hydrogenolysis of the N-chiral group). A model is reported for the origin of the stereoselectivity through an enol ester−diacetoxyborohydride 6, which affords the intramolecular reduction. By choosing the appropriate chiral amine, this procedure allows a straightforward preparation of both the enantiopure β-amino esters and derivatives with known biological activity, using readily available starting materials and inexpensive reagents and conditions.

No abstract

No abstract

No abstract

Two series of 1,4-dioxanes (4-11 and 12-19) were rationally designed and prepared to interact either with the phencyclidine (PCP) binding site of the N-methyl-d-aspartate (NMDA) receptor or with σ1 receptors, respectively. The biological profiles of the novel compounds were assessed using radioligand binding assays, and the compounds with the highest affinities were investigated for their functional activity. The results were in line with the available pharmacophore models and highlighted that the 1,4-dioxane scaffold is compatible with potent antagonist activity at NMDA receptor or high affinity for σ1 receptors. The primary amines 6b and 7 bearing a cyclohexyl and a phenyl ring or two phenyl rings in position 6, respectively, were the most potent noncompetitive antagonists at the NMDA receptor with IC50 values similar to those of the dissociative anesthetic (S)-(+)-ketamine. The 5,5-diphenyl substitution associated with a benzylaminomethyl moiety in position 2, as in 18, favored the interaction with σ1 receptors.

No abstract