A 4-HO-TEMPO-catalyzed redox strategy for the synthesis of pyridines through the annulation of cyclopropanols and oxime acetates has been developed. This protocol features good functional group tolerance and high chemoselectivity and also promises to be efficient for the late-stage functionalization of skeletons of drugs and natural products. Mechanism studies indicate that the reaction involves the in situ generated α,β-unsaturated ketones and imines as the key intermediates, which are derived from cyclopropanols and oxime acetates via a TEMPO/TEMPOH redox cycle, respectively. The pyridine products are formed as a result of annulation of enones with imines followed by TEMPO-catalyzed oxidative aromatization by excess oxime acetates. This method not only realizes the TEMPO-catalyzed redox reaction but also broadens the frontiers for TEMPO in catalysis.

A novel, efficient, and facile approach for the synthesis of structurally important pyrimidines has been successfully developed by Cu-catalyzed and 4-HO-TEMPO-mediated [3 + 3] annulation of commercially available amidines with saturated ketones. This method provides a new protocol for the synthesis of pyrimidines by a cascade reaction of oxidative dehydrogenation/annulation/oxidative aromatization via direct β-C(sp)-H functionalization of saturated ketones followed by annulation with amidines.

A novel vicinal sulfoximation of alkenes was achieved under mild and metal-free conditions by using readily available sulfinic acids as the sulfonating agent and tert-butyl nitrite (TBN) as the radical initiator and the oxime source.

Source of material 1-hydrogen-2-ethyl-4,5-imidazole dicarboxylate acid (0.019 g, 0.1 mmol), Co(CH 3 CH 2 COO) ⋅ 4H 2 O(0.025 g, 0.1 mmol), and NaOH (0.004 g, 0.1 mmol) were added to water (10 ml) in aTeflon-lined stainless-steel reactor. The mixture was heated at 403 K for 4d,and then slowly cooled down to room temperature. Pink block-shaped crystals of the title compound were obtained. DiscussionThe design and construction of metal-organic coodination polymers is of current interest in the field of supramocular chemistry and crystal engineering. The effective and facile approach for the synthesis of such complexes is still the appropriate choice. It is well known carboxylate ligands play an important role in coodination chemistry [1,2]. On the other hand, N-containing auxiliary ligands may tune the structures of the resultant metalorganic complexes [3][4][5][6]. The asymmetric unit of the title crystal structure consists of a1H-hydrogen-2-ethyl-4,5-imidazoledicarboxylate, aCo(II) ion and a 1,3-di(4-pyridyl)-propane. Co ion is six-coordinated by two carboxlate oxygen atoms and two Natoms of two 1H-2-ethyl-4,5-imidazoledicarboxylate and two Na toms of two 1,3-di(4-pyridyl)propane, forming ad istorted octahedron with.128(2) Å.Furthermore, CoN 4O2 octahedra are bridged by two symmetry-related bipyridyl molecules and two symmetry-related 1H-2-ethyl-4,5-imidazoledicarboxylate molecules forming aone-dimensional chain.