Lyle W. Castle

Chromate Oxidation of α-Nitro Alcohols to α-Nitro Ketones: Significant Improvements to a Classic Method

A series of eight alkyl and aryl α-nitro ketones were prepared by the potassium dichromate oxidation of the corresponding nitro alcohols. Short reaction times allowed for the easy isolation of pure nitro ketones that are devoid of starting materials and/or other oxidation side products.

Complexes of (bpy)2Ru(II) and (Ph2bpy)2Ru(II) with a series of thienophenanthroline ligands: synthesis, characterization, and electronic spectra

A series of complexes (bpy)2LRu(II) and (Ph2bpy)2LRu(II), where bpy is 2,2′-bipyridine, Ph2bpy is 4,4′-diphenyl-2,2′-bipyridine and L is 1,10-phenanthroline (phen), [1]benzothieno[2,3-c][1,10]phenanthroline (btp), naphtho[1′,2′ : 5,4]thieno[2,3-c][1,10]phenanthroline [ntpl, l=linear], and naphtho[1′,2′ : 4,5]thieno[2,3-c][1,10]phenanthroline (ntph, h=helical) were synthesized and characterized using 2D COSY NMR spectra. The UV spectra were assigned to study their metal to ligand charge transfer (MLCT) excited states. Complexes of (bpy)2LRu(II) showed identical absorption wavelengths (λ max) for the MLCT of all four members of the series with the only variation being the intensity (log ε ) for each. The MLCT of (Ph2bpy)2LRu(II) showed the similar behavior only with different wavelengths showing that in this heteroleptic series of complexes the MLCT is exclusively to the bpy ligands with none to thienophenanthroline (btp, ntpl, or ntph).

The acid catalyzed conversion of 1,3,5-trimethyl-2,4,6-tris(2-pyridyl)hexahydro-s-triazine into the asymmetric monomer, N-methylpyridine-2-carboxaldimine

Abstract This paper discusses the nature of the products formed from the reaction of 2-pyridinecarboxaldehyde and methylamine. The synthesized products manifest themselves in two distinct forms, one an oil and the other crystalline, which have identical chemical properties but differ dramatically in their spectroscopic parameters. A novel trimeric structure, the hexahydro- s -triazine, is suggested for the crystalline form, while the oil appears to be the monomeric N -methyl pyridine-2-carboxaldimine. IR, UV–vis, Raman and NMR spectroscopies are used to validate the proposed structures. The conversion of the trimeric crystalline form to the monomeric oil form, is acid-catalyzed and occurs rapidly.