Thionation of Aminophthalimide Hindered Carbonyl Groups and Application to the Synthesis of 3,6′-Dithionated Pomalidomides

Herein, we present a new one-pot procedure for the 3,6′-dithionation of pomalidomide derivatives in which the key 3-position sulfur atom is preferentially installed at the desired (but sterically congested) carbonyl of the aminophthalimide system and with regiochemistry distinct from Lawesson’s Reagent thionation methods. When heated in 1,4-dioxane with P4S10–pyridine complex, pomalidomides are smoothly and reproducibly converted into their 3,6′-dithionated analogues in roughly 30% isolated yield and at various scales. While detrimental to the desired 3,6′-type outcome when employing Lawesson’s Reagent, we hypothesize that the pomalidomide aniline group instead facilitates P4S10-type thionation at the otherwise hindered 3-position carbonyl, contributing to the selectivity observed. When paired with classical methods of thionation, this approach offers an interesting and appealing addition to the synthetic toolbox, permitting facile late-stage access to complementary thionated pomalidomides in direct single-flask procedures.

Influence of ligand substituent conformation on the spin state of an iron(ii)/di(pyrazol-1-yl)pyridine complex

The temperature of the solution-phase spin-crossover equilibrium in iron(ii) complexes of 4-alkylsulfanyl-2,6-di{pyrazol-1-yl}pyridine (bppSR) complexes depends strongly on the alkylsulfanyl substituent.

Synthesis, Structure and Antioxidant Activity of Mixed Ruthenium(III) Benzoyl Pyridine Complex

A new ruthenium arsine complex was prepared by reacting equimolar ratio of [RuBr3(AsPh3)3] and 2-benzoyl pyridine. It was characterized by microanalysis, FT-IR and single crystal X-ray diffraction studies. X-ray diffraction data showed the distorted octahedral geometry of the complex. The pyridine nitrogen and carbonyl oxygen of the ligand coordinated with the metal center. Antioxidant activity of the complex was analyzed using different assays, which manifested significant activity. It has been found that a newly synthesized complex possessed better antioxidant activity than the ligand and precursor complex.

Threefold Spiral Structure Constructed by 1D Chains of [[M(NCS)2(bpa)2]·biphenyl]n (M = Fe, Co; bpa = 1,2-bis(4-pyridyl)ethane)

Assembled complexes [[M(NCS)2(bpa)2]·biphenyl]n (M = Fe, Co; bpa = 1,2-bis(4-pyridyl)ethane) have been synthesized because [Fe(NCBH3)2(bpa)2·biphenyl]n has a novel threefold spiral structure and shows stepwise spin-crossover phenomenon. We attempted to obtain spiral structures for [[Fe(NCS)2(bpa)2]·biphenyl]n and [[Co(NCS)2(bpa)2]·biphenyl]n using a one-step diffusion method, while the reported spiral structure of [[Fe(NCBH3)2(bpa)2]·biphenyl]n was obtained by diffusion method after synthesizing Fe(II)-pyridine complex. X-ray structural analysis revealed that [[Fe(NCS)2(bpa)2]·biphenyl]n and [[Co(NCS)2(bpa)2]·biphenyl]n had a chiral propeller structure of pyridines around the central metal, and they had a novel spiral structure and chiral space group P3121 without the presence of chiral auxiliaries. It was shown that the host 1D chain, having a chiral propeller structure of pyridines around the central metal along with its concerted interaction with an atropisomer of biphenyl, made a threefold spiral structure.