- Charge Accumulation and Multi-Electron Photoredox Chemistry with a Sensitizer–Catalyst–Sensitizer Triad
-
Photoinduced electron transfer in donor–sensitizer–acceptor compounds usually leads to simple electron–hole pairs, and photoredox catalysis typically relies on single-electron transfer (SET) events. This work reports on a molecular triad able to accumulate two electrons on a central dibenzo[1,2]dithiin moiety flanked by two peripheral RuII photosensitizers. Under continuous illumination, the doubly reduced form of the dibenzo[1,2]dithiin undergoes thiolate–disulfide exchange with an aliphatic disulfide substrate, thereby acting as a two-electron catalyst after two initial SET events with triethylamine at the RuII sensitizers. The use of a relatively simple triad for coupling two separate SET processes to a subsequent two-electron reduction is an important conceptual advance from photoinduced SET and light-driven charge accumulation towards multi-electron photoredox catalysis. This is relevant for artificial photosynthesis and light-driven multi-electron chemistry in general.
- Nomrowski, Julia,Guo, Xingwei,Wenger, Oliver S.
-
p. 14084 - 14087
(2018/09/11)
-
- Micellar systems
-
A complex is described that is deliverable to a cell comprising inserting a nucleic acid or other cargo into a reverse micelle. The reverse micelle has the property to compact the nucleic acid for easier delivery.
- -
-
-
- 4-hydroxyquinoline-3-carboxamides and hydrazides as antiviral agents
-
The present invention provides 4-hydroxyquinoline-3-carboxamide and hydrazide compounds of formula I These compounds are useful to treat or prevent the herpesviral infections, particularly, human cytomegaloviral infection.
- -
-
-
- Interleukin-2/viral antigen protein chimers
-
Disclosed are (1) a fused protein obtained by combining an antigen used for vaccine and a lymphokine by the application of gene engineering, (2) a recombinant DNA containing a nucleotide sequence coding for the above fused protein, (3) a transformant bearing the above recombinant DNA, (4) a method for producing the fused protein which comprises cultivating the above transformant, producing and accumulating the above fused protein in a culture, and collecting the fused protein, and (5) a hybrid protein obtained by chemically combining an antigen used for vaccine with a lymphokine. The resulting fused and hybrid proteins have strong immunogenicity.
- -
-
-
- BIOLOGICALLY ACTIVE COMPOUNDS ISOLATED FROM AEROBIC FERMENTATION OF TRICHODERMA VIRIDE
-
This invention relates to compounds of structural formula (I) isolated from an aerobic fermentation of Trichoderma viride MF5628, ATCC 74084: (I) which are squalene synthase inhibitors and thus useful as cholesterol lowering agents. These compounds are also potent antifungal agents. Additionally, they inhibit farnesyl protein transferase and farnesylation of the oncogene protein Ras and are thus useful in treating cancer. This invention also relates to a process for obtaining compounds of structural formula (I)
- -
-
-
- Process for reconfiguring keratin fibre
-
A process of recofiguring keratin fibre is disclosed. The process includes rolling, winding, curling, looping lapping, folding, twirling, bending, curving, twisting, coiling, twining, entwining or straightening the keratin fibre or leaving the keratin fibre unchanged. A reducing agent is then applied to the keratin fibre to reduce cystine disulfide linkages and other susceptible linkages in the keratin fibre. An oxidizing agent is applied to the keratin fibre having the reducing agent, to set cystine disulfide linkages in the keratin fibre. The reducing agent and the oxidizing agent are then removed from the keratin fibre by rinsing the keratin fibre.
- -
-
-
- Bleomycin conjugates and method
-
A bleomycin conjugate for use in targeting a compound to a body tumor. The conjugate includes an oxidized bleomycin/cobalt(III) complex and the compound to be targeted joined to the complex through a monodentate cobalt/sulfur coordinate bond. Also disclosed are methods for preparing the conjugate, and for targeting the compound to a body tumor, for purposes of tumor radioimaging or therapy.
- -
-
-
- Polyfunctional disulfide compounds having S--S exchange reactivity
-
A polyfunctional disulfide compound, useful as a cross-linking reagent having S--S exchange reactivity, of the formula STR1 wherein R is 2-benzothiazolyl or 2-pyridyl-N-oxide and X is a spacer group having an alkylene group directly bonded to each S--S group.
- -
-
-
- Rate Constants and Equilibrium Constants for Thiol-Disulphide Interchange Reactions Involving Oxidized Glutathione
-
The rate of reduction of oxidized glutathione (GSSG) to glutathione (GSH) by thiolate (RS-) follows a Broensted relation in pKas of the conjugate thiols (RSH): βnuc ca. 0.5.This value is similar to that for reduction of Ellman's reagent: βnuc ca. 0.4 - 0.5.Analysis of a number of rate and equilibrium data, taken both from this work and from the literature, indicates that rate constants, k, for a range of thiolate-disulphide interchange reactions are correlated well by equations of the form log k = C + βnucpKanuc + βcpKac + βlgpKalg ( nuc = nucleophile, c = central, and lg = leaving group sulfur): eq 36 - 38 give representative values of the Broensted coefficients.The values of these Bronsted coefficients are not sharply defined by the available experimental data, although eq 36 - 38 provide useful kinetic models for rates of thiolate-disulfide interchange reactions.The uncertainty in these parameters is such that their detailed mechanistic interpretation is not worthwhile, but their qualitative interpretation - that all three sulphur atoms experience a significant effective negative charge in the transition state, but that the charge is concentrated on the terminal sulfurs - is justified.Equilibrium constants for reduction of GSSG using α,ω-dithiols have been measured.The reducing potential of the dithiol is strongly influenced by the size of the cyclic disulfide formed on its oxidation: the most strongly reducing dithiols are those which can form six-membered cyclic disulfides.Separate equilibrium constants for thiolate anion-disulphide interchange (KS-) and for thiol-disufide interchange (KSH) have been estimated from literature data: KS- is roughly proportional to 2ΔpKa is the difference between the pKas of the two thiols involved in the interchange.The contributions of thiol pKa values to the observed equilibrium constants for reduction of GSSG with α,ω-dithiols appear to be much smaller than those ascribable to the influence of structure on intramolecular ring formation.These equilibrium and rate constants are helpful in choosing dithiols for use as antioxidants in solutions containing proteines: dithiothreitol (DTT), 1,3-dimercapto-2-propanol (DMP), and 2-mercaptoethanol have especially useful properties.
- Szajewski, Richard P.,Whitesides, George M.
-
p. 2011 - 2026
(2007/10/02)
-
- Thiopolymers, their derivatives and methods for their preparation and use
-
A method for producing products for separation, ion exchange or as basic material for the preparation of various derivatives designed for separation purposes and adsorption purposes by means of a polymer being activated with a reagent containing at least two bifunctional groups so that at least one of the reactive, functional groups in each molecule is bonded to the polymer while leaving a considerable amount of remaining groups unreacted but still reactive so that the activated polymer can be caused to react with thiosulphate after surplus reagent has been eliminated. The invention also relates to the produced products or their derivatives consisting of a water-soluble hydroxyl group or amino group containing polymer substituted with organic side-chains, each containing one or more thiosulphate groups or derivatives of such groups and the use of the products for purification of water, separation, immobilization of enzymes, etc.
- -
-
-
