a-Methoxyand a-ethoxyketones, as important intermediates in organic synthesis and flavor compounds in food chemistry, were synthesized by deprotonation of N-(1-alkoxy-2-propylidene)isopropylamine, prepared by condensation of the corresponding a-alkoxyacetone with isopropylamine, and subsequent reaction of the corresponding 1-azaallylic anions with alkyl halides to afford a¢-alkylated, a-alkylat...

Reaction of thiols with the 1,2-dithiolan-3-one 1-oxide heterocycle found in leinamycin (1) results in the conversion of this antitumor antibiotic to a DNA-alkylating episulfonium ion (5). While the products formed in this reaction have been rationalized by a mechanism involving initial attack of thiol on the central sulfenyl sulfur (S2') of the 1,2-dithiolan-3-one 1-oxide ring, the carbonyl ca...

Dispersion of nuclear fibers of the spermatozoa of dogfish, man, and bull is made possible after treatment with a reducing and alkylating reagent coupled with an anionic detergent; the same detergent used at a low ionic strength dissociates the nuclear content of the rainbow trout sperm. Electron microscopy of such dispersed nuclear fibers has shown a beads-on-a-string configuration for these f...

several cell lines.S-iO} In the cells undergoing apoptosis, there are characteristic morphological and biochemical changes such as cell shrinkage, membrane blebbing, chromatin condensation, and DNA fragmentation, resulting in an oligonucleosomal ladder. Some of these characteristic apoptotic features have been observed in ricin-treated cells.S・7'iO) It has been proposed that a unique family of ...

One of the principal problems facing nucleic acid delivery systems using polyplexes is the instability of the complexes in the presence of proteins and high salt concentrations. We have used a cross-linking polymer to overcome this problem. Pendant thiol moieties have been incorporated into a PAA (polyamidoamine) homopolymer and a PEG [poly(ethylene glycol)]-PAA-PEG copolymer reported previousl...

The 2-iminothiolane reaction with protein amino groups adds a spacer arm ending with a thiol group, which can be further treated with molecules carrying a maleimido ring. This approach is currently used for the preparation of a candidate 'blood substitute' in which human Hb (haemoglobin) is conjugated with long chains of PEG [poly(ethylene glycol)]. To identify the thiolation sites by MS, we ha...

By taking advantage of the orthogonal nature of thiol-ene coupling and anhydride based esterification reactions, a facile and chemoselective strategy to dendritic macromolecules has been developed. The ability to interchange growth steps based on thiol-ene and anhydride chemistry allows the synthesis of fifth-generation dendrimers in only five steps and under benign reaction conditions. In addi...

Glutathione (γ-L-glutamyl-L-cysteinyl-glycine, GSH) is the most abundant low molecular weight, thiol-containing compound within the cells and has a primary role in the antioxidant defense and intracellular signaling. Here we demonstrated that nutrient deprivation led to a significant decrease of intracellular GSH levels in three different carcinoma cell lines. This phenomenon was dependent on A...

We describe the fabrication of porous foams with shape memory triggering at body temperature. Employing a modified porogenleaching technique, functionalized poly(3-caprolactone) (PCL) and poly(ethylene glycol) (PEG) macromers are crosslinked via thiol–ene chemistry to generate highly porous foam scaffolds with shape memory capacity. The temperature at which shape change of these scaffolds occur...