Role of 1,4-dimethylpiperazine in radical cyclizations

金沢大学医薬保健研究域薬学系Radical cyclization of o-ethenyltrichloroacetanilides in boiling 1,4-dimethylpiperazine was examined with a comparison of the mode of radical cyclizations under a Bu3SnH-mediated condition. It was found that an attack of a hydrogen atom on the cyclized radical intermediates occurred more rapidly in 1,4-dimethylpiperazine than under the Bu3SnH-mediated condition. This phenomenon was also observed in similar reactions of N- ethenyltrichloroacetamide. ©ARKAT USA, Inc

π-Extended Fluoranthene Imide Derivatives: Synthesis, Structures, and Electronic and Optical Properties

Diels-Alder reactions of acenaphthylene-5,6-dicarboximide (AI) derivatives with the corresponding dienes afforded some derivatives of π-extended fluoranthene imide, namely N-(2-ethylhexyl)-7,10-diphenylfluoranthene imide (DPFI) and N-(2-ethylhexyl)-7,8,9,10-tetraphenylfluoranthene imide (TPFI), N-(n-octyl)-benzo[k]fluoranthene imide (BFI), and N-(n-octyl)-naphtho[k]fluoranthene imide (NFI). Molecular structures of TPFI and BFI reveal that the core π-skeletons have a highly planar structure, and the molecules form a dimeric structure in the crystals. The absorption spectra exhibit bathochromic shift with π-extension of the core π-skeletons. On the other hand, DPFI and TPFI show the long-wavelength emission related to BFI, probably due to π-extension toward the phenyl substituents in the excited states. BFI and NFI exhibited an interesting concentration-dependent 1H-NMR behavior in CDCl3, suggesting self-aggregation formation. Moreover, BFI and NFI show moderate and remarkable solvatofluorochromism in solutions (BFI for ΔλEM = 67 nm, NFI for ΔλEM = 116 nm), respectively, while DPFI and TPFI show weak solvatofluorochromism. The density functional theory calculations demonstrate that the considerable spatial separation between the HOMO and LUMO coefficients in the NFI molecule. The result indicates that the ground-to-excited state transition of NFI should have intramolecular charge transfer (ICT) character.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Human Embryonic Stem Cell-Derived Cardiomyocytes Regenerate the Infarcted Pig Heart but Induce Ventricular Tachyarrhythmias

Summary: Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) show considerable promise for regenerating injured hearts, and we therefore tested their capacity to stably engraft in a translationally relevant preclinical model, the infarcted pig heart. Transplantation of immature hESC-CMs resulted in substantial myocardial implants within the infarct scar that matured over time, formed vascular networks with the host, and evoked minimal cellular rejection. While arrhythmias were rare in infarcted pigs receiving vehicle alone, hESC-CM recipients experienced frequent monomorphic ventricular tachycardia before reverting back to normal sinus rhythm by 4 weeks post transplantation. Electroanatomical mapping and pacing studies implicated focal mechanisms, rather than macro-reentry, for these graft-related tachyarrhythmias as evidenced by an abnormal centrifugal pattern with earliest electrical activation in histologically confirmed graft tissue. These findings demonstrate the suitability of the pig model for the preclinical development of a hESC-based cardiac therapy and provide new insights into the mechanistic basis of electrical instability following hESC-CM transplantation. : In this article, Laflamme and colleagues show that the transplantation of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) partially remuscularizes the scar of infarcted and appropriately immunosuppressed pigs. hESC-CM recipients exhibited frequent monomorphic ventricular tachycardia before reverting back to normal sinus rhythm by 4 weeks post transplantation. These graft-related tachyarrhythmias were found to be due to focal mechanisms rather than macro-reentry. Keywords: human embryonic stem cell-derived cardiomyocytes, pluripotent stem cells, myocardial infarction, ventricular tachyarrhythmias, electroanatomical mapping, MR