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Oh, Seohee,Kim, Seji,Lee, Dayoung,Gwak, Jinseong,Lee, Yunho American Chemical Society 2016 Inorganic Chemistry Vol.55 No.24
<P>Two pathways of alkoxide migration occurring at a nickel(II) center supported by a PPP ligand (PPP- = P[2-(PPr2)-Pr-i-C6H4](2) ) are presented in this Article. In the first route, the addition of a pi-acidic ligand to a (PPP)Ni alkoxide species reveals the formation of a PO bond. This reaction occurs via metalligand cooperation (MLC) involving a 2-electron reduction at nickel. To demonstrate a PO bond formation, a nickel(II) isopropoxide species (PPP)Ni((OPr)-Pr-i) (4) was prepared. Upon addition of a pi-acidic isocyanide ligand (CNBu)-Bu-t, a nickel(0) isocyanide species ((PPP)-P-OiPr)Ni((CNBu)-Bu-t) (6b) was generated; PO bond formation occurred via reductive elimination (RE). When CO is present, migratory insertion (MI) occurs instead. The reaction of 4 with CO(g) results in the formation of (PPP)Ni((COOPr)-Pr-i) (5), representing an alternative pathway. The corresponding RE product ((PPP)-P-OiPr)Ni(CO) (6a) can be independently produced from the substitution reaction of {((PPP)-P-OiPr)Ni}(2)(mu-N-2) (3) with CO(g). While two different carbonylation pathways in 4 seem feasible, CO bond forming migratory insertion singly occurs. Regeneration of a (PPP)Ni moiety via a PO bond cleavage was demonstrated by treating 3 with CO2(g). The formation of (PPP)Ni((OCOOPr)-Pr-i) (7) clearly shows that an isopropoxide group migrates onto the bound CO2 ligand, and a PNi moiety is regenerated.</P>
Reversible Intramolecular P–S Bond Formation Coupled with a Ni(0)/Ni(II) Redox Process
Oh, Seohee,Lee, Yunho American Chemical Society 2016 Organometallics Vol.35 No.10
<P>P-S bond formation/cleavage mediated by a nickel ion supported by a PPP ligand (PPP = P[2-(PPr2)-Pr-i-C6H4](2)(-)) has been investigated herein. To gain an entry into this chemistry, a mononuclear thiolato nickel complex, (PPP)Ni(SAr) (1a,b) was prepared by treating the chloride starting material with NaSPh. Upon carbonylation, this complex produces a nickel(0) monocarbonyl species, ((PPP)-P-SAr)Ni(CO) (2a,b), in which the thiolate migrates onto the central P of the ligand to give a P-S bond and two electron reduction of a nickel(II) center. The reaction undergoes via a pseudo-first-order decay with respect to consumption of a nickel(II) thiolato species, suggesting an intramolecular reaction under the excess CO(g) conditions. The reverse reaction involving P-S bond cleavage with concomitant decarbonylation occurs to regenerate 1 a,b in benzene. Reaction of 2a with trityl chloride results in Ph3CSPh formation, whereas the reaction with MeI gives methylation at a phosphide moiety or a thiolate group.</P>
( Seohee Oh ),( Yu-sun Sung ),( Mihee Jang ),( Yong-jin Kim ),( Hyun-wook Park ),( Dukhee Nho ),( Dong-gun Lee ),( Hyeon Woo Yim ),( Sung-yeon Cho ) 대한내과학회 2024 The Korean Journal of Internal Medicine Vol.39 No.3
Background/Aims: Since the coronavirus disease 2019 (COVID-19) outbreak, hospitals have implemented infection control measures to minimize the spread of the virus within facilities. This study aimed to investigate the impact of COVID-19 on the incidence of healthcare-associated infections (HCAIs) and common respiratory virus (cRV) infections in hematology units. Methods: This retrospective study included all patients hospitalized in Catholic Hematology Hospital between 2019 and 2020. Patients infected with vancomycin-resistant Enterococci (VRE), carbapenemase-producing Enterobacterales (CPE), Clostridium difficile infection (CDI), and cRV were analyzed. The incidence rate ratio (IRR) methods and interrupted time series analyses were performed to compare the incidence rates before and after the pandemic. Results: The incidence rates of CPE and VRE did not differ between the two periods. However, the incidence of CDI increased significantly (IRR: 1.41 [p = 0.002]) after the COVID-19 pandemic. The incidence of cRV infection decreased by 76% after the COVID-19 outbreak (IRR: 0.240 [p < 0.001]). The incidence of adenovirus, parainfluenza virus, and rhinovirus infection significantly decreased in the COVID-19 period (IRRs: 0.087 [p = 0.003], 0.031 [p < 0.001], and 0.149 [p < 0.001], respectively). Conclusions: The implementation of COVID-19 infection control measures reduced the incidence of cRV infection. However, CDI increased significantly and incidence rates of CPE and VRE remained unchanged in hematological patients after the pandemic. Infection control measures suitable for each type of HCAI, such as stringent hand washing for CDI and enough isolation capacities, should be implemented and maintained in future pandemics, especially in immunocompromised patients.
Choi Seohee,Min Jae-Seok,Jeong Sang-Ho,Yoo Moon-Won,Son Young-Gil,Oh Sung Jin,Kim Jong-Han,Park Joong-Min,Hur Hoon,Jee Ye Seob,Hwang Sun-Hwi,Jin Sung-Ho,Lee Sang Eok,Lee Young-Joon,Seo Kyung Won,Park 대한위암학회 2022 Journal of gastric cancer Vol.22 No.1
Purpose: Tegafur/gimeracil/oteracil (S-1) and capecitabine plus oxaliplatin (CAPOX) are standard adjuvant chemotherapies (ACs) administered after gastrectomy to patients with stage II or III gastric cancer. However, the effcacy of AC in elderly patients remains unclear. The objective of this retrospective multicenter cohort study was to compare the effcacies of S-1 and CAPOX AC in patients aged ≥70 years. Materials and Methods: Nine hundred eighty-three patients who were treated with AC using S-1 (768 patients) or CAPOX (215 patients) were enrolled in this study. Each patient underwent AC after curative gastrectomy for stage II or III gastric cancer at one of 27 hospitals in the Republic of Korea between January 2012 and December 2013. Relapse-free survival (RFS) and overall survival (OS) were analyzed according to AC regimen and age group. Results: Of the 983 patients, 254 (25.8%) were elderly. This group had a similar RFS (P=0.099) but significantly poorer OS (p=0.003) compared with the non-elderly group. Subgroup analysis of the non-elderly group revealed no AC-associated differences in survival. Subgroup analysis of the elderly group revealed significantly better survival in the S-1 group than in the CAPOX group (RFS, P<0.001; OS, P<0.001). Multivariate analysis revealed that the CAPOX regimen was an independent poor prognostic factor for RFS (hazard ratio [HR], 1.891; 95% confidence interval [CI], 1.072–3.333; P=0.028) and OS (HR, 2.970; 95% CI, 1.550–5.692; P=0.001). Conclusions: This multicenter observational cohort study found significant differences in RFS and OS between S-1 and CAPOX AC among patients with gastric cancer aged ≥70 years.
Synthesis of α-(4-Oxazolyl)amino Esters via Brønsted Acid Catalyzed Tandem Reaction
Lee, Ansoo,Oh, Seohee,Kim, Hyunwoo American Chemical Society 2018 ORGANIC LETTERS Vol.20 No.11
<P>A one-step, Brønsted acid catalyzed tandem reaction for the synthesis of α-(4-oxazolyl)amino esters was developed. 4-Nitrobenzenesulfonic acid was found to be an efficient catalyst for the coupling of ethyl 2-oxobut-3-ynoates with amides to provide various α-(4-oxazolyl)amino esters. The experimental and X-ray crystallographic data suggest that a series of bond-forming reactions including imine formation, intermolecular Michael addition, and intramolecular Michael addition are involved to generate both the oxazole and amino acid functionalities.</P> [FIG OMISSION]</BR>
Kim, Yeong-Eun,Oh, Seohee,Kim, Seji,Kim, Onnuri,Kim, Jin,Han, Sang Woo,Lee, Yunho American Chemical Society 2015 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.137 No.13
<P>Reversible transformations are observed between a phosphide-nickel(II) alkoxide and a phosphinite-nickel(0) species via a P–O bond formation coupled with a 2-e<SUP>–</SUP> redox change at the nickel center. In the forward reaction, the nickel(0) dinitrogen species (PP<SUP>OMe</SUP>P)Ni(N<SUB>2</SUB>) (<B>2</B>) and {(PP<SUP>OMe</SUP>P)Ni}<SUB>2</SUB>(μ-N<SUB>2</SUB>) (<B>3</B>) were formed from the reaction of (PPP)NiCl (<B>1</B>) with a methoxy anion. In the backward reaction, a (PPP)Ni(II) moiety was regenerated from the CO<SUB>2</SUB> reaction of <B>3</B> with the concomitant formation of a methyl carbonate ligand in (PPP)Ni(OCOOMe) (<B>7</B>). Thus, unanticipated metal–ligand cooperation involving a phosphide based ligand is reported.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2015/jacsat.2015.137.issue-13/ja513112r/production/images/medium/ja-2014-13112r_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja513112r'>ACS Electronic Supporting Info</A></P>