A fluorene-based photoinitiator, a preparation method thereof, a photocurable composition having the same, and use thereof in the field of photocuring are disclosed. In some embodiments, the fluorene-based photoinitiator has a structure represented by Formula I, wherein X is -A-(X).sub.n, wherein A is selected from a heteroatom which is selected from O, N, or S, X is selected from a C.sub.1-C.sub.20 linear alkyl group, a C.sub.1-C.sub.20 branched alkyl group, a C.sub.3-C.sub.8 cycloalkyl group, a C.sub.1-C.sub.10 alkyl group substituted with a C.sub.3-C.sub.8 cycloalkyl group or one or more of carbon atoms in X are substituted with a heteroatom, and n is 1 or 2; and R.sub.4 is a hydroxy group or a N-morpholinyl group. In some embodiments, the fluorene-based photoinitiator comprises a structure represented by Formula II.

A fluorene-based photoinitiator, a preparation method thereof, a photocurable composition having the same, and use thereof in the field of photocuring are disclosed. In some embodiments, the fluorene-based photoinitiator has a structure represented by Formula I, wherein X is -A-(X).sub.n, wherein A is selected from a heteroatom which is selected from O, N, or S, X is selected from a C.sub.1-C.sub.20 linear alkyl group, a C.sub.1-C.sub.20 branched alkyl group, a C.sub.3-C.sub.8 cycloalkyl group, a C.sub.1-C.sub.10 alkyl group substituted with a C.sub.3-C.sub.8 cycloalkyl group or one or more of carbon atoms in X are substituted with a heteroatom, and n is 1 or 2; and R.sub.4 is a hydroxy group or a N-morpholinyl group. In some embodiments, the fluorene-based photoinitiator comprises a structure represented by Formula II.

The present invention relates to a method for preparing difluoroallylboronate and application thereof, and it belongs to a field of compound preparation. A method for preparing difluoroallyl borate ester is using a compound of the formula II and bis (pinacolato) diboron as raw materials in a solvent and in the presence of an iron catalyst and a base according to the following reaction formula, to obtain a compound of the formula I,

##STR00001##

The method of the present invention directly use an inexpensive, commercially available metal iron salt as a catalyst to provide a convenient, low-cost method for preparing difluoroallyl borate ester, and provide a new and effective approach for the synthesis of -aminobutyric acid receptor agonist (III).

The present invention relates to a method for preparing difluoroallylboronate and application thereof, and it belongs to a field of compound preparation. A method for preparing difluoroallyl borate ester is using a compound of the formula II and bis (pinacolato) diboron as raw materials in a solvent and in the presence of an iron catalyst and a base according to the following reaction formula, to obtain a compound of the formula I,

##STR00001##

The method of the present invention directly use an inexpensive, commercially available metal iron salt as a catalyst to provide a convenient, low-cost method for preparing difluoroallyl borate ester, and provide a new and effective approach for the synthesis of -aminobutyric acid receptor agonist (III).

The present invention is directed to inhibitors of tyrosinase, pharmaceutical compositions comprising such tyrosinase inhibitors, and methods of making and using the same. Specifically, included in the present invention are compositions of matter comprised of at least one 2,4-dihydroxybenzene analog, which inhibit the activity of tyrosinase and which inhibit the overproduction of melanin.

The present invention is directed to inhibitors of tyrosinase, pharmaceutical compositions comprising such tyrosinase inhibitors, and methods of making and using the same. Specifically, included in the present invention are compositions of matter comprised of at least one 2,4-dihydroxybenzene analog, which inhibit the activity of tyrosinase and which inhibit the overproduction of melanin.

The present invention is directed to inhibitors of tyrosinase, pharmaceutical compositions comprising such tyrosinase inhibitors, and methods of making and using the same. Specifically, included in the present invention are compositions of matter comprised of at least one 2,4-dihydroxybenzene analog, which inhibit the activity of tyrosinase and which inhibit the overproduction of melanin.

A method of reducing the virulence of a bacterium that expresses accessory gene regulator A (AgrA) includes administering to the bacterium an amount of AgrA antagonist effective to inhibit the synthesis of one or more virulence factors by the bacterium.

A method of reducing the virulence of a bacterium that expresses accessory gene regulator A (AgrA) includes administering to the bacterium an amount of AgrA antagonist effective to inhibit the synthesis of one or more virulence factors by the bacterium.

The invention provides compounds that are inhibitors of bacterial RNA polymerase. The invention also provides compositions comprising such compounds, methods of making such compounds, and methods of using said compounds. The invention has applications in control of bacterial gene expression, control of bacterial growth, antibacterial chemistry, and antibacterial therapy.