Novel selective synthesis route to introduce primary alkyl groups on aromatic compounds is disclosed. The synthesis route is based on electrophilic aromatic substitutions of thionium ion species that are generated in-situ from aldehydes and thiols, affording benzyl sulfide that can be reduced with triethylsilane.

Dithioamine reducing agents useful for the reduction of disulfide bonds. The reducing agents of this invention are useful, for example, to reduce disulfide bonds, particularly in proteins, or to prevent the formation of disulfide bonds, particularly in proteins and other biological molecules. Reducing agents of this invention can be employed to regulate protein function in proteins in which a sulfhydryl group is associated with biological activity. Reducing agents of this invention can prevent inactivation of a given protein or enhance activation of a given protein or other biological molecule in vitro and/or in vivo. Reducing agents of this invention can prevent or reduce oxidation of cysteine residues in proteins and prevent the formation of reduced activity protein dimers (or other oligomers). Reducing agents of this invention are useful and suitable for application in a variety of biological applications, particularly as research and synthetic reagents. The invention provides S-acylated dithioamines which can be selectively activated reducing agents by removal of the S-acyl groups enzymatically or chemically. The invention further provides dithiane precursors of thioamino reducing agents. The invention provides dithioamine reducing agents, S-acylated dithioamines and dithianes which are immobilized on surfaces, including among others, glass, quartz, microparticles, nanoparticles and resins.

Dithioamine reducing agents useful for the reduction of disulfide bonds. The reducing agents of this invention are useful, for example, to reduce disulfide bonds, particularly in proteins, or to prevent the formation of disulfide bonds, particularly in proteins and other biological molecules. Reducing agents of this invention can be employed to regulate protein function in proteins in which a sulfhydryl group is associated with biological activity. Reducing agents of this invention can prevent inactivation of a given protein or enhance activation of a given protein or other biological molecule in vitro and/or in vivo. Reducing agents of this invention can prevent or reduce oxidation of cysteine residues in proteins and prevent the formation of reduced activity protein dimers (or other oligomers). Reducing agents of this invention are useful and suitable for application in a variety of biological applications, particularly as research and synthetic reagents. The invention provides S-acylated dithioamines which can be selectively activated reducing agents by removal of the S-acyl groups enzymatically or chemically. The invention further provides dithiane precursors of thioamino reducing agents. The invention provides dithioamine reducing agents, S-acylated dithioamines and dithianes which are immobilized on surfaces, including among others, glass, quartz, microparticles, nanoparticles and resins.

The invention provides a diamine crosslinking agent for acidic polysaccharides consisting of a diamine compound having a primary amino group at both terminals and an ester or thioester bond in the molecule, wherein the number of atom in the linear chain between at least one of the amino groups and the carbonyl carbon in the ester or thioester is 1 to 5; in particular, a diamine crosslinking agent for acidic polysaccharides which is represented by the general formula (I) below: ##STR00001##
[the symbols in the formula are as described in the specification]; a crosslinked acidic polysaccharide obtained by forming crosslinks by amide bonding between the amino groups in the diamine crosslinking agent and carboxyl groups in an acidic polysaccharide; and a medical material including the crosslinked product.

The invention provides a diamine crosslinking agent for acidic polysaccharides consisting of a diamine compound having a primary amino group at both terminals and an ester or thioester bond in the molecule, wherein the number of atom in the linear chain between at least one of the amino groups and the carbonyl carbon in the ester or thioester is 1 to 5; in particular, a diamine crosslinking agent for acidic polysaccharides which is represented by the general formula (I) below: ##STR00001##
[the symbols in the formula are as described in the specification]; a crosslinked acidic polysaccharide obtained by forming crosslinks by amide bonding between the amino groups in the diamine crosslinking agent and carboxyl groups in an acidic polysaccharide; and a medical material including the crosslinked product.

The present application includes dendrons of Formula I, compositions comprising these dendrons and uses thereof, in particular for the delivery of agents such as nucleic acids and drugs to cells and subjects.

##STR00001##

wherein each Repeating Group is the same or different.

According to the present invention, there is provided a method for producing carboxylic acid thioester, comprising reacting a compound represented by the following formula (I), carboxylic acid and thiol in the presence of a catalyst including at least one Group 2 metal compound. The production method is a production method which is simple in reaction operation, which places a small load on the environment and the human body and which enables carboxylic acid thioester to be catalytically obtained at a high yield even at a normal temperature and a normal pressure (25 C., 1 atm). In the formula (I), R.sup.1 and R.sup.2 each independently represent a hydrocarbon group having 1 to 20 carbon atoms.

##STR00001##

According to the present invention, there is provided a method for producing carboxylic acid thioester, comprising reacting a compound represented by the following formula (I), carboxylic acid and thiol in the presence of a catalyst including at least one Group 2 metal compound. The production method is a production method which is simple in reaction operation, which places a small load on the environment and the human body and which enables carboxylic acid thioester to be catalytically obtained at a high yield even at a normal temperature and a normal pressure (25 C., 1 atm). In the formula (I), R.sup.1 and R.sup.2 each independently represent a hydrocarbon group having 1 to 20 carbon atoms.

##STR00001##

The present invention relates to synthetic organic antioxidants of small molecules. The novel dithiol-containing compounds in this invention possess strongest possible capability as both scavenger for free radicals and antioxidant. This invention is directed to novel molecules as prodrugs of the novel dithiol-containing compounds, their rational design, their feasible preparation route by means of synthetic organic chemistry, and their potential uses in application to treatment and/or prevention of major diseases associated with oxidative stress, such as Alzheimer's disease, Parkinson's disease, cancer, diabetes, HIV, acne, cardiovascular disease, renal disease, hypertension, hypercholesterolemia, hyperlipidemia, rheumatoid arthritis, inflammation, pain, aging, stroke, cataract, glaucoma, age-related macular degeneration, etc.

The present invention relates to synthetic organic antioxidants of small molecules. The novel dithiol-containing compounds in this invention possess strongest possible capability as both scavenger for free radicals and antioxidant. This invention is directed to novel molecules as prodrugs of the novel dithiol-containing compounds, their rational design, their feasible preparation route by means of synthetic organic chemistry, and their potential uses in application to treatment and/or prevention of major diseases associated with oxidative stress, such as Alzheimer's disease, Parkinson's disease, cancer, diabetes, HIV, acne, cardiovascular disease, renal disease, hypertension, hypercholesterolemia, hyperlipidemia, rheumatoid arthritis, inflammation, pain, aging, stroke, cataract, glaucoma, age-related macular degeneration, etc.