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Tetrahedron, 2008
The α-acetoxylation of indanones and tetralones by using Mn(OAc)3 followed by the enzyme catalyze... more The α-acetoxylation of indanones and tetralones by using Mn(OAc)3 followed by the enzyme catalyzed kinetic resolution of acetoxy ketones furnished both of the enantiomers of α-acetoxy ketones in good chemical and optical yields. The Baeyer–Villiger oxidation of α-acetoxy ketones with m-CPBA, CF3SO3H, and CH2Cl2, at rt gives the corresponding lactones without racemization. The acetoxy ketone moiety migrates selectively in order
The Journal of Organic Chemistry, 2007
New cyanation/phosphonate-phosphate rearrangement/C-acylation reactions of cyanophosphate anion w... more New cyanation/phosphonate-phosphate rearrangement/C-acylation reactions of cyanophosphate anion with cyanoformate esters are described. Phase-transfer cocatalysts facilitate cyanide-catalyzed reactions between acyl phosphonates and cyanoformates to afford protected tertiary carbinol products in good to excellent yields (74-95%). Ethyl cyanoformate is used as a cyanide source and electrophile. The scope of the reaction was investigated by using a number of benzoyl and acyl phosphonates along with ethyl cyanoformate. Representative chemoselective reduction of the product 5a afforded ethyl 3-amino-2-hydroxy-2-phenylpropanoate (13) in good yield.
Turkish Journal of Pharmaceutical Sciences, 2021
INTRODUCTION: Racecadotril is an anti-diarrheal drug that has the indication to reduce the secret... more INTRODUCTION: Racecadotril is an anti-diarrheal drug that has the indication to reduce the secretion of water and electrolytes into the intestine. It is known to have an unpleasant taste when administered orally. The aim of the present study was to develop a pharmaceutical racecadotril dispersible tablet, which masks the bitter taste using the wet granulation method. For this reason, the effect of the amount of ethylacrylatemethylmethacrylate copolymers (Eudragit® NE 30D) on taste masking and in-vitro dissolution of the finished product was investigated. METHODS: The taste masked racecadotril granules were prepared using Eudragit® NE 30D and the ratio between the amounts of racecadotril and Eudragit® NE 30D involved in the formulation was optimized. The products obtained in the dispersible tablet dosage form were evaluated in terms of taste and in-vitro dissolution studies. The in-vitro dissolution profiles of the products obtained from this study were compared with reference product Tiorfan® Granules for Oral Suspension manufactured by Bioprojet Pharma (Paris, France). A method of apparatus II (paddle), 900 mL, pH 4.5 acetate buffer + 1% sodium dodecyl sulfate (SDS) and 100 rpm at 37.0 ± 0.5°C was adopted. RESULTS: The results of the studies have shown that the formulation should have Eudragit® NE 30D higher than 1% by weight of racecadotril to satisfy the tastemasking ability, and also the formulation should have Eudragit® NE 30D equal or lower than 10% by weight of racecadotril to have better release characteristic to be compatible with the reference product. DISCUSSION AND CONCLUSION: The obtained results demonstrated that a chemically long term stable racecadotril dispersible tablet product whose taste is efficiently masked by using wet granulation method with an acceptable release profile was obtained with Eudragit® NE 30D ratio higher than 1% and equal or lower than 10% by weight of racecadotril. The developed formulation has the ability to increase patient compliance.
Chiral hydroxylated cyclopentane derivatives are important precursors for biologically active com... more Chiral hydroxylated cyclopentane derivatives are important precursors for biologically active compounds. Synthesis of these types of compounds in optically pure form found increased interest in pharmaceutical chemistry. 2-ethylcyclopentane-1.3-dione was acetoxylated using manganese III acetate at preferred positions. Enzyme catalyzed enantioselective hydrolysis or enantioselective acetoxylation of hydrolyzed acetoxy derivatives gives the corresponding hydroxylated diketones in optically pure form.
Highly flexible and efficient syntheses of 1,2,3,5-substituted pyrroles starting from 2-propynyl-... more Highly flexible and efficient syntheses of 1,2,3,5-substituted pyrroles starting from 2-propynyl-1,3-dicarbonyl compounds and amines are presented. TFA catalyzed formation of the pyrroles is suggested to proceed through sequential amination of the carbonyl compounds followed by regioselective 5-exo-dig cyclization of the enaminone intermediate and aromatization.
Tetrahedron, 2008
The α-acetoxylation of indanones and tetralones by using Mn(OAc)3 followed by the enzyme catalyze... more The α-acetoxylation of indanones and tetralones by using Mn(OAc)3 followed by the enzyme catalyzed kinetic resolution of acetoxy ketones furnished both of the enantiomers of α-acetoxy ketones in good chemical and optical yields. The Baeyer–Villiger oxidation of α-acetoxy ketones with m-CPBA, CF3SO3H, and CH2Cl2, at rt gives the corresponding lactones without racemization. The acetoxy ketone moiety migrates selectively in order
The Journal of Organic Chemistry, 2007
New cyanation/phosphonate-phosphate rearrangement/C-acylation reactions of cyanophosphate anion w... more New cyanation/phosphonate-phosphate rearrangement/C-acylation reactions of cyanophosphate anion with cyanoformate esters are described. Phase-transfer cocatalysts facilitate cyanide-catalyzed reactions between acyl phosphonates and cyanoformates to afford protected tertiary carbinol products in good to excellent yields (74-95%). Ethyl cyanoformate is used as a cyanide source and electrophile. The scope of the reaction was investigated by using a number of benzoyl and acyl phosphonates along with ethyl cyanoformate. Representative chemoselective reduction of the product 5a afforded ethyl 3-amino-2-hydroxy-2-phenylpropanoate (13) in good yield.
Turkish Journal of Pharmaceutical Sciences, 2021
INTRODUCTION: Racecadotril is an anti-diarrheal drug that has the indication to reduce the secret... more INTRODUCTION: Racecadotril is an anti-diarrheal drug that has the indication to reduce the secretion of water and electrolytes into the intestine. It is known to have an unpleasant taste when administered orally. The aim of the present study was to develop a pharmaceutical racecadotril dispersible tablet, which masks the bitter taste using the wet granulation method. For this reason, the effect of the amount of ethylacrylatemethylmethacrylate copolymers (Eudragit® NE 30D) on taste masking and in-vitro dissolution of the finished product was investigated. METHODS: The taste masked racecadotril granules were prepared using Eudragit® NE 30D and the ratio between the amounts of racecadotril and Eudragit® NE 30D involved in the formulation was optimized. The products obtained in the dispersible tablet dosage form were evaluated in terms of taste and in-vitro dissolution studies. The in-vitro dissolution profiles of the products obtained from this study were compared with reference product Tiorfan® Granules for Oral Suspension manufactured by Bioprojet Pharma (Paris, France). A method of apparatus II (paddle), 900 mL, pH 4.5 acetate buffer + 1% sodium dodecyl sulfate (SDS) and 100 rpm at 37.0 ± 0.5°C was adopted. RESULTS: The results of the studies have shown that the formulation should have Eudragit® NE 30D higher than 1% by weight of racecadotril to satisfy the tastemasking ability, and also the formulation should have Eudragit® NE 30D equal or lower than 10% by weight of racecadotril to have better release characteristic to be compatible with the reference product. DISCUSSION AND CONCLUSION: The obtained results demonstrated that a chemically long term stable racecadotril dispersible tablet product whose taste is efficiently masked by using wet granulation method with an acceptable release profile was obtained with Eudragit® NE 30D ratio higher than 1% and equal or lower than 10% by weight of racecadotril. The developed formulation has the ability to increase patient compliance.
Chiral hydroxylated cyclopentane derivatives are important precursors for biologically active com... more Chiral hydroxylated cyclopentane derivatives are important precursors for biologically active compounds. Synthesis of these types of compounds in optically pure form found increased interest in pharmaceutical chemistry. 2-ethylcyclopentane-1.3-dione was acetoxylated using manganese III acetate at preferred positions. Enzyme catalyzed enantioselective hydrolysis or enantioselective acetoxylation of hydrolyzed acetoxy derivatives gives the corresponding hydroxylated diketones in optically pure form.
Highly flexible and efficient syntheses of 1,2,3,5-substituted pyrroles starting from 2-propynyl-... more Highly flexible and efficient syntheses of 1,2,3,5-substituted pyrroles starting from 2-propynyl-1,3-dicarbonyl compounds and amines are presented. TFA catalyzed formation of the pyrroles is suggested to proceed through sequential amination of the carbonyl compounds followed by regioselective 5-exo-dig cyclization of the enaminone intermediate and aromatization.