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 for producing an α,β-unsaturated aldehyde, including reacting a compound represented by formula (I) with a compound represented by formula (II) in the presence or absence of a solvent to provide a compound represented by formula (III), wherein titanium oxide is used as a catalyst, and an amount of the solvent is 50 parts by mass or less relative to 100 parts by mass in total of the compound of formula (I) and the compound of formula (II),

##STR00001##

A method for producing an α,β-unsaturated aldehyde, including reacting a compound represented by formula (I) with a compound represented by formula (II) in the presence or absence of a solvent to provide a compound represented by formula (III), wherein titanium oxide is used as a catalyst, and an amount of the solvent is 50 parts by mass or less relative to 100 parts by mass in total of the compound of formula (I) and the compound of formula (II),

##STR00001##

A method for producing an α,β-unsaturated aldehyde, including reacting a compound represented by formula (I) with a compound represented by formula (II) in the presence or absence of a solvent to provide a compound represented by formula (III), wherein titanium oxide is used as a catalyst, and an amount of the solvent is 50 parts by mass or less relative to 100 parts by mass in total of the compound of formula (I) and the compound of formula (II),

##STR00001##

Described is a process of making pseudoionone and hydroxy pseudoionone comprising the steps of (i) preparing a first aqueous mixture comprising first concentrations of acetone, citral and hydroxide, (ii) producing a second aqueous mixture by allowing to react for a reaction time the components of the first aqueous mixture and (iii) producing a third aqueous mixture by adding to the second aqueous mixture a second amount of hydroxide so that an additional amount of pseudoionone is formed in the third aqueous mixture. The invention further suggests an apparatus for making pseudoionone and hydroxy pseudoionone as well as to a respective process and use of said apparatus in making pseudoionone and hydroxy pseudoionone.

Described is a process of making pseudoionone and hydroxy pseudoionone comprising the steps of (i) preparing a first aqueous mixture comprising first concentrations of acetone, citral and hydroxide, (ii) producing a second aqueous mixture by allowing to react for a reaction time the components of the first aqueous mixture and (iii) producing a third aqueous mixture by adding to the second aqueous mixture a second amount of hydroxide so that an additional amount of pseudoionone is formed in the third aqueous mixture. The invention further suggests an apparatus for making pseudoionone and hydroxy pseudoionone as well as to a respective process and use of said apparatus in making pseudoionone and hydroxy pseudoionone.

Described is a process of making pseudoionone and hydroxy pseudoionone comprising the steps of (i) preparing a first aqueous mixture comprising first concentrations of acetone, citral and hydroxide, (ii) producing a second aqueous mixture by allowing to react for a reaction time the components of the first aqueous mixture and (iii) producing a third aqueous mixture by adding to the second aqueous mixture a second amount of hydroxide so that an additional amount of pseudoionone is formed in the third aqueous mixture. The invention further suggests an apparatus for making pseudoionone and hydroxy pseudoionone as well as to a respective process and use of said apparatus in making pseudoionone and hydroxy pseudoionone.

Naphthoquinone derivatives of Lawsone have been found to be effective against Staphylococcus aureus and methicillin resistant Staphylococcus aureus (MRSA). Such compounds generally contain a substituent group at the 3-position of a specific naphthoquinone compound, i.e. 2-hydroxy-1,4-naphthoquinone. One of these derivatives referred to as compound 6c in the series exhibits potent antimicrobial activity that is comparable to that of the two commercial antibiotics ofloxacin and ciprofloxacin against the two strains of methicillin sensitive Staphylococcus aureus (MSSA; ATCC 29213 and ATCC 6538). In the case of two strains of MRSA (ATCC BAA-44 and ATCC BAA-1717) that have developed drug resistance to both ofloxacin and ciprofloxacin, the antimicrobial activity of 6c can almost rival that of vancomycin and daptomycin. Furthermore, 6c is also effective against vancomycin-intermediate and daptomycin non-susceptible strain of MRSA (ATCC 700699). Besides the efficacy, 6c has a much improved drug resistance profile in comparison with the conventional antibiotics.

Naphthoquinone derivatives of Lawsone have been found to be effective against Staphylococcus aureus and methicillin resistant Staphylococcus aureus (MRSA). Such compounds generally contain a substituent group at the 3-position of a specific naphthoquinone compound, i.e. 2-hydroxy-1,4-naphthoquinone. One of these derivatives referred to as compound 6c in the series exhibits potent antimicrobial activity that is comparable to that of the two commercial antibiotics ofloxacin and ciprofloxacin against the two strains of methicillin sensitive Staphylococcus aureus (MSSA; ATCC 29213 and ATCC 6538). In the case of two strains of MRSA (ATCC BAA-44 and ATCC BAA-1717) that have developed drug resistance to both ofloxacin and ciprofloxacin, the antimicrobial activity of 6c can almost rival that of vancomycin and daptomycin. Furthermore, 6c is also effective against vancomycin-intermediate and daptomycin non-susceptible strain of MRSA (ATCC 700699). Besides the efficacy, 6c has a much improved drug resistance profile in comparison with the conventional antibiotics.