Epoxide ring opening in a zinc(II) complex in water without any Lewis acid catalyst: Formation of only one diastereomer out of 23

Brønsted Acid-Catalysed Epoxide Ring-Opening Using Amine Nucleophiles: A facile access to β-amino alcohols

A mild, efficient, and metal-free synthetic protocol for the synthesis of β-amino alcohols is reported. The reaction proceeds at room temperature with only 0.5 mol% catalyst loading and affords β-amino alcohol derivatives in excellent yield. This protocol is well-tolerated by a wide range of styrene oxide and aniline derivatives. A notably efficacious gram-scale synthesis is also reported with a high TON = 842. Further, the Hammett correlation study was also performed to identify the rate-determining step.

Highly regioselective ring-opening of epoxides with amines: a metal- and solvent-free protocol for the synthesis of β-amino alcohols

We herein report a metal- and solvent-free acetic acid-mediated ring-opening reaction of epoxides with amines. This process provides β-amino alcohols in high yields with excellent regioselectivity. Importantly, this epoxide ring-opening protocol can be used for the introduction of amines in natural products during late-stage transformations.

A facile and versatile methodology for cysteine specific labeling of proteins with octahedral polypyridyl d⁶ metal complexes

We have synthesized and characterized four octahedral polypyridyl d(6) metal complexes bearing the 5,6-epoxy-5,6-dihydro-[1,10]phenanthroline ligand (L1) as cysteine specific labeling reagents. The proposed synthetic pathways allow the preparation of the metal complexes containing Re(I), Ru(II), Os(II) and Ir(III) while preserving the epoxide functionality. The complexes were characterized by (1)H and (13)C NMR, mass spectrometry, UV-visible and luminescence spectroscopies as well as cyclic voltammetry. As proof of concept, a set of non-native single cysteine P450 BM3 heme domain mutants previously developed in our laboratory was used to study the labeling reaction. We demonstrate that the proposed labels can selectively react, often in high yield, with cysteine residues of the protein via the nucleophilic thiol ring opening of the epoxide moiety. In addition, under basic conditions, subsequent loss of a water molecule led to the aromatization of the phenanthroline ring on the protein-bound label compounds, as observed by mass spectrometry and luminescence measurements.

Theoretical and Experimental Studies on the Regioselectivity of Epoxide Ring Opening by Nucleophiles in Nitromethane without any Catalyst: Nucleophilic-Chain Attack Mechanism

We describe here a mild and efficient method for the nucleophilic ring-opening of epoxides with amines, alcohols and water in the presence of nitromethane as a polar solvent without using any catalyst. The reactions are highly regioselective and afford the products in excellent yields within a short period of time at room temperature. The regioselectivity for this ring opening has been investigated using experimental and theoretical 1H and 13C NMR studies together with activation energy calculations at the B3LYP/6-311+G(2d,p) level of theory. The mechanism of nucleophilic attack has been investigated in terms of a direct attack or a methanol chain attack.

Separation of Functionalized 5,6-Disubstituted-1,10-Phenanthroline for Dye-Sensitized Solar Cell Applications

5,6-Epoxy-1,10-phenanthroline is used as a convenient starting material for 5-hydroxy-6-Aryl-1,10-phenanthroline ligands containing carboxylic and sulfonic groups useful for further anchoring of the sensitizer on TiO2for dye-sensitized solar cells (DSCs). Based on the crystal growth of the mixture of products, a convenient separation route for the extension of the p-system on 5,6-disubstituted-1,10-phenanthroline was used to develop a novel series of functionalized 1,10-phenanthroline ligands with electron-withdrawing end-capping group. Also, we report the epoxy opening of 5,6-epoxy-1,10-phenanthroline by aromatic amines stoichiometrically in refluxing water and ethanol in the absence of any catalyst. The dyes were characterized by1H-NMR, FT-IR, UV-Vis, and X-ray single crystal diffraction analyses. It crystallizes in the monoclinic space groupC 2/c,a= 20.920(4) Å,b= 10.340(2) Å,c= 16.187(3) Å,β= 92.30(3)°,V= 3498.6(12) Å3, andZ= 8. The reaction details and features were described in detail.

Ligand substituents effect on 10Dq

Reaction of 5,6-dihydro-5,6-epoxy-1,10-phenanthroline (L) with Ni(ClO(4))(2)·6H(2)O in methanol in 3:1M proportion at room temperature yields [NiL(3)](ClO(4))(2)·2H(2)O. The X-ray crystal structure of the cation NiL(3)(2+) has been determined. Aminolysis of the three epoxide rings in NiL(3)(2+) by 4-substituted anilines in boiling water without any Lewis acid catalyst gives a family of Ni(II) complexes with octahedral NiL(6)(2+) core. In these complexes, crystal field splitting 10Dq varies from 11601 to 15798 cm(-1) in acetonitrile. The variation in 10Dq is found to be satisfactorily linear (r(2)=0.951) with the Hammett σ(R) parameter of the substituent on the anilino fragment. 10Dq increases with the increase in the electron donation ability of the substituent.