Selenophilic reaction of organolithium and magnesium reagents with phosphinoselenoic chlorides

The reaction of phosphinoselenoic chlorides 1 with various organolithium and magnesium reagents was studied. Sequential reaction of phosphinoselenoic chlorides 1 with organolithium and magnesium reagents and elemental selenium gave two types of products, phosphine selenides 2 and phosphinodiselenoic acid esters 3 . The esters 3 appeared to be formed via the selenophilic reaction of organolithium and magnesium reagents with the chlorides 1 . Molecular orbital calculations were carried out for model compounds H₂P(E)Cl (E = O, S and Se) to determine their electronic structures. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:185–191, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20091     

Surface-grafted multiporphyrin arrays as light-harvesting antennae to amplify photocurrent generation

Organized multiporphyrin arrays were developed on the conductive surface by a novel coordination-directed molecular architecture aiming at efficient photoelectric conversion. The basic strategy employs the mutual coordination of two imidazolylporphyrinatozinc(II) units to form a cofacial dimer. Thus, meso,meso-linked bis(imidazolylporphyrinatozinc) (Zn2(ImP)2) was organized onto imidazolylporphyrinatozinc on the gold substrate as a self-assembled monolayer. The organized Zn2(ImP)2 bearing allyl side chains was covalently linked by ring-closing olefin metathesis catalyzed with Grubbs catalyst. Alternating coordination/metathesis reactions allow the stepwise accumulation of multiporphyrin arrays on the gold electrode. A successive increase in absorption over a wide wavelength range occurred after each accumulation step of Zn2(ImP)2 on the gold electrode, and cathodic photocurrent generation was enhanced in the aqueous electrolyte system, containing viologen as an electron carrier. The significant increase of the photocurrent indicates that the multiporphyrin array works as a "light-harvesting antenna" on the gold electrode.     

Reaction of acetoxyazetidinones with trimethylsilylacetyl thiolesters: preparation of azetidinone-thiolester precursors to carbapenems

Reaction of acetoxyazetidinones, $\text{1}$ and $\text{2}$, with trimethylsilyl- acetyl thiolesters $\text{10}$ afforded azetidinone-thiolesters, $\text{11}$ and $\text{12}$, which are useful intermediates in the carbapenem synthesis.     

Reaction of 5-amino-1-phenylpyrazole-4-carbonitriles with dimethyl acetylenedicarboxylate. Synthesis and structural determination of trimethyl 4,8-dioxo-1-phenyl-4,5,5a,8-tetrahydro-1H-pyrazolo[3,4-e]indolizine-5,5a,6-tricarboxylate derivatives

The reaction of 5-amino-1-phenylpyrazole-4-carbonitriles 1a-c with dimethyl acetylenedicarboxylate in the presence of potassium carbonate in dimethyl sulfoxide gave trimethyl 4,5,5a,8-tetrahydro-1-phenyl-4,8-dioxo-1H-pyrazolo[3,4-e]indolizine-5,5a,6-tricarboxylate derivatives 3a-c from the basic solution. The products were formed by a double Michael reaction of 1 with dimethyl acetylenedicarboxylate followed by cyclization to the cyano group. The structure of product 3a was established by X-ray crystallography.     

Structural design of stimuli‐responsive bioconjugated hydrogels that respond to a target antigen

Stimuli‐responsive bioconjugated hydrogels that can respond to a target antigen (antigen‐responsive hydrogels) were prepared by introducing antigen‐antibody bindings as reversible crosslinks into the gel networks. The preparation conditions of the antigen‐responsive hydrogels and the mechanism of the antigen‐responsive behavior were investigated, focusing on bioconjugated hydrogel structures. This article also focuses on the effect of semi‐interpenetrating polymer network (semi‐IPN) structures on the antigen‐responsive swelling/shrinking behavior of bioconjugated hydrogels with antigen‐antibody bindings. The preparation conditions and the network structures of the bioconjugated hydrogels are discussed in relation to designing antigen‐responsive hydrogels. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2144–2157, 2009