RESUMO
This work focused on the preparation and investigation of polyurethane (SO-PU)-containing sunflower oil glycerides. By transesterification of sunflower oil with glycerol, we synthesized a glyceride mixture with an equilibrium composition, which was used as a new diol component in polyurethanes in addition to poly(ε-caprolactone)diol (PCLD2000). The structure of the glyceride mixture was characterized by physicochemical methods, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), nuclear magnetic resonance spectroscopy (NMR), and size exclusion chromatography (SEC) measurements. The synthesis of polyurethanes was performed in two steps: first the prepolymer with the isocyanate end was synthesized, followed by crosslinking with an additional amount of diisocyanate. For the synthesis of the prepolymer, 4,4'-methylene diphenyl diisocyanate (MDI) or 1,6-hexamethylene diisocyanate (HDI) were used as isocyanate components, while the crosslinking was carried out using an additional amount of MDI or HDI. The obtained SO-PU flexible polymer films were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The so-obtained flexible SO-PU films were proved to be suitable for the preparation of potentially biocompatible and/or biodegradable scaffolds. In addition, the stress versus strain curves for the SO-PU polymers were interpreted in terms of a mechanical model, taking into account the yield and the strain hardening.
Assuntos
Polímeros , Poliuretanos , Óleo de Girassol , Poliuretanos/química , Polímeros/química , Óleo de Girassol/química , Materiais Biocompatíveis/química , Isocianatos/química , Poliésteres/química , Espectroscopia de Ressonância Magnética , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
In this work, the preparation and systematic investigation of cross-linked polyurethane-epoxy (PU-EP) polymer systems are reported. The PU-EP polymers were prepared using a reaction of isocyanate (NCO)-terminated PU-prepolymer with diglycidyl ether of bisphenol A (DGEBA)-amine cooligomer. The oligomerization of DGEBA was carried out by adding furfurylamine (FA) or ethanolamine (EA), resulting in DGEBA-amine cooligomers. For the synthesis of NCO-terminated PU-prepolymer, poly(ε-caprolactone)diol (PCD) (Mn = 2 kg/mol) and 1,6-hexamethylene diisocyanate (HDI) were used. The cross-linking was achieved by adding DGEBA-amine cooligomer to PU-prepolymer, in which the obtained urethane bonds, due to the presence of free hydroxil groups in the activated DGEBA, served as netpoints. During cross-linking, ethanolamine provides an additional free hydroxyl group for the formation of a new urethane bond, while furfurylamine can serve as a thermoreversible coupling element (e.g., Diels-Alder adduct). The PU-EP networks were characterized using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA) and scanning electron microscopy (SEM). The DMA curves of some PU-EPs (depending on the compositions and the synthetic method) revealed a plateau-like region above the melting temperature (Tm) of PCD, confirming the presence of a cross-linked structure. This property resulted in a shape memory (SM) behavior for these samples, which can be fine-tuned in the presence of furfurylamine through the formation of additional thermoreversible bonds (e.g., Diels-Alder adduct).
RESUMO
In this paper, the synthesis, characterization, and properties of crosslinked poly(ε-caprolactone)-based polyurethanes as potential tissue replacement materials are reported. The polyurethane prepolymers were prepared from poly(ε-caprolactone)diol (PCD), polyethylene glycol (PEG)/polylactic acid diol (PLAD), and 1,6-hexamethylene diisocyanate (HDI). In these segmented polyurethanes, the role of PEG/PLAD was to tune the hydrophobic/hydrophilic character of the resulting polymer while sucrose served as a crosslinking agent. PLAD was synthesized by the polycondensation reaction of D,L-lactic acid and investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nuclear magnetic resonance spectroscopy (NMR). The crosslinked polyurethane samples (SUPURs) obtained were characterized by attenuated total reflectance Fourier-transform infrared spectroscopy (AT-FT-IR), swelling, and mechanical (uniaxial tensile tests) experiments. The thermo and thermomechanical behavior were studied by differential scanning calorimetry (DSC) and dynamical mechanical analysis (DMA). The viability of dental pulp stem cells was investigated in the case of polyurethanes composed of fully biocompatible elements. In our studies, none of our polymers showed toxicity to stem cells (DPSCs).
Assuntos
Poliuretanos , Sacarose , Materiais Biocompatíveis/química , Poliésteres/química , Polietilenoglicóis/química , Polímeros , Poliuretanos/química , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Sucrose-1,6-hexamethylene diisocyanate (HDI) cooligomers were synthesized and used as new polyols for poly(ε-caprolactone) (PCL)-based polyurethanes. The polyaddition reaction of sucrose and HDI was monitored by MALDI-TOF MS. It was found that by selecting appropriate reaction conditions, mostly linear oligomer chains containing 16 sucrose units could be obtained. For the synthesis of polyurethane networks, prepolymers were prepared by the reaction of poly(ε-caprolactone) (PCL, 10 kg/mol) with HDI or 4,4'-methylene diphenyl diisocyanate (MDI) and were reacted with sucrose-HDI cooligomers. The so-obtained sucrose-containing polyurethanes were characterized by means of attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FT IR), swelling, mechanical (uniaxial tensile tests) and differential scanning calorimetry (DSC).
Assuntos
Isocianatos/química , Poliuretanos/síntese química , Sacarose/química , Varredura Diferencial de Calorimetria , Teste de Materiais , Poliésteres/síntese química , Poliésteres/química , Poliuretanos/química , Espectroscopia de Infravermelho com Transformada de Fourier , TemperaturaRESUMO
In this report, the synthesis of poly(ω-pentadecalactone) (PPDL) (co)polymers and their incorporation into polyurethanes (PUs) are reported. Optimal conditions for the ring-opening polymerization (ROP) of ω-pentadecalactone (PDL) using dibutyltin dilaurate catalyst were established. For the synthesis of linear and crosslinked PUs, 50 kDa poly(ε-caprolactone) (PCL) and 1,6-hexamethylenediisocyanate (HDI) were used. The obtained polyurethanes were characterized by Attenuated Total Reflectance Fourier-Transform Infrared spectroscopy (AT-FTIR), differential scanning calorimetry (DSC), and dynamical mechanical analysis (DMA). The DMA of the selected sample showed a rubbery plateau on the storage modulus versus temperature curve predicting shape memory behavior. Indeed, good shape memory performances were obtained with shape fixity (Rf) and shape recovery (Rr) ratios.
RESUMO
The design of glycogen phosphorylase (GP) inhibitors targeting the catalytic site of the enzyme is a promising strategy for a better control of hyperglycaemia in the context of type 2 diabetes. Glucopyranosylidene-spiro-heterocycles have been demonstrated as potent GP inhibitors, and more specifically spiro-oxathiazoles. A new synthetic route has now been elaborated through 1,3-dipolar cycloaddition of an aryl nitrile oxide to a glucono-thionolactone affording in one step the spiro-oxathiazole moiety. The thionolactone was obtained from the thermal rearrangement of a thiosulfinate precursor according to Fairbanks' protocols, although with a revisited outcome and also rationalised with DFT calculations. The 2-naphthyl substituted glucose-based spiro-oxathiazole 5h, identified as one of the most potent GP inhibitors (Ki = 160 nM against RMGPb) could be produced on the gram-scale from this strategy. Further evaluation in vitro using rat and human hepatocytes demonstrated that compound 5h is a anti-hyperglycaemic drug candidates performing slightly better than DAB used as a positive control. Investigation in Zucker fa/fa rat model in acute and subchronic assays further confirmed the potency of compound 5h since it lowered blood glucose levels by â¼36% at 30 mg kg-1 and â¼43% at 60 mg kg-1. The present study is one of the few in vivo investigations for glucose-based GP inhibitors and provides data in animal models for such drug candidates.
Assuntos
Inibidores Enzimáticos/farmacologia , Glucose/metabolismo , Glicogênio Fosforilase/antagonistas & inibidores , Hipoglicemiantes/farmacologia , Compostos de Espiro/farmacologia , Tiazóis/farmacologia , Animais , Glicemia/metabolismo , Ciclização , Teoria da Densidade Funcional , Glicogênio/metabolismo , Glicogênio Fosforilase/metabolismo , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/química , Concentração Inibidora 50 , Cinética , Lactonas/síntese química , Lactonas/química , Oxirredução , Ratos Zucker , Compostos de Espiro/síntese química , Compostos de Espiro/química , Estereoisomerismo , Temperatura , Tiazóis/síntese química , Tiazóis/químicaRESUMO
Human liver glycogen phosphorylase (hlGP), a key enzyme in glycogen metabolism, is a valid pharmaceutical target for the development of new anti-hyperglycaemic agents for type 2 diabetes. Inhibitor discovery studies have focused on the active site and in particular on glucopyranose based compounds with a ß-1 substituent long enough to exploit interactions with a cavity adjacent to the active site, termed the ß-pocket. Recently, C-ß-d-glucopyranosyl imidazoles and 1, 2, 4-triazoles proved to be the best known glucose derived inhibitors of hlGP. Here we probe the ß-pocket by studying the inhibitory effect of six different groups at the para position of 3-(ß-d-glucopyranosyl phenyl)-5-phenyl-, 1, 2, 4-triazoles in hlGP by kinetics and X-ray crystallography. The most bioactive compound was the one with an amine substituent to show a Ki value of 0.43⯵M. Structural studies have revealed the physicochemical diversity of the ß-pocket providing information for future rational inhibitor design studies.
Assuntos
Inibidores Enzimáticos/farmacologia , Glicogênio Fosforilase/antagonistas & inibidores , Fígado/enzimologia , Triazóis/farmacologia , Animais , Domínio Catalítico/efeitos dos fármacos , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Glicogênio Fosforilase/isolamento & purificação , Glicogênio Fosforilase/metabolismo , Humanos , Cinética , Modelos Moleculares , Estrutura Molecular , Coelhos , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/químicaRESUMO
The present work aimed at the preparation and investigation of different epoxy-polyurethane (EP-PU) co-networks. The EP-PU co-networks were obtained by applying two different synthetic strategies, in which the coupling element, the Dielsâ»Alder (DA) adduct, was prepared previously or formed "in situ" in the reaction between furan functionalized polyurethane and furfuryl amine-diglycidyl ether bisphenol-A oligomers (FA_DGEBA). For the synthesis of these EP-PU networks, poly(ε-caprolactone)-diol (PCD, Mn = 2 kg/mol) and poly(ε-caprolactone) (PCL) with different molecular weights (Mn = 10, 25 and 50 kg/mol) and 1,6-hexamethylenediisocyanate (HDI) were used. The EP-PU co-networks were characterized by Attenuated Total Reflectance Fourier-Transform Infrared spectroscopy (AT-FT-IR), differential scanning calorimetry (DSC) and dynamical mechanical analysis (DMA). Scanning electron microscopy (SEM) was applied to assess the morphology of the EP-PU samples. It was demonstrated that the stressâ»strain curves for the EP-PUs could be interpreted based on the Standard Linear Solid (SLS) model. The DMA traces of some EP-PUs (depending on the composition and the synthetic method) revealed a plateau-like region above the melting temperature (Tm) of PCL confirming the presence of cross-linked structure. This feature predicted shape memory (SM) behavior for these EP-PU samples. Indeed, very good shape fixity and moderate shape recovery were obtained. The shape recovery processes of these EP-PU samples were described using double exponential decay functions.
RESUMO
Reactions of O-peracetylated (α-D-galacto-heptulopyranosyl bromide)onamide and O-perbenzoylated (α-D-gluco-heptulopyranosyl bromide)onamide with ketones in the presence of silver(I) salt promoters gave the corresponding O-peracylated 1',5'-anhydro-D-glycitol-spiro-[1',5]-4-imino-2,2-disubstituted-1,3-dioxolanes. The D-galacto configured starting compounds furnished both spiro epimers, while the D-gluco counterparts yielded only configurationally inverted products. Under acidic conditions, O-perbenzoylated α-D-gluco-heptulopyranosonamide and ketones yielded the protected 1',5'-anhydro-D-glucitol-spiro-[1',5]-2,2-disubstituted-oxazolidin-4-ones, which were O-debenzoylated by the Zemplén protocol. These compounds had no inhibition against rabbit muscle glycogen phosphorlyase b.
Assuntos
Amidas/química , Glicosídeos/química , Cetonas/química , Solventes/química , Compostos de Espiro/química , Acilação , Animais , Inibidores Enzimáticos/química , Coelhos , EstereoisomerismoRESUMO
New derivatives of d-xylose with aglycons of the most efficient glucose derived inhibitors of glycogen phosphorylase were synthesized to explore the specificity of the enzyme towards the structure of the sugar part of the molecules. Thus, 2-(ß-d-xylopyranosyl)benzimidazole and 3-substituted-5-(ß-d-xylopyranosyl)-1,2,4-triazoles were obtained in multistep procedures from O-perbenzoylated ß-d-xylopyranosyl cyanide. Cycloadditions of nitrile-oxides and O-peracetylated exo-xylal obtained from the corresponding ß-d-xylopyranosyl cyanide furnished xylopyranosylidene-spiro-isoxazoline derivatives. Oxidative ring closure of O-peracetylated ß-d-xylopyranosyl-thiohydroximates prepared from 1-thio-ß-d-xylopyranose and nitrile-oxides gave xylopyranosylidene-spiro-oxathiazoles. The fully deprotected test compounds were assayed against rabbit muscle glycogen phosphorylase b to show moderate inhibition for 3-(2-naphthyl)-5-(ß-d-xylopyranosyl)-1,2,4-triazole (IC50=0.9mM) only.
Assuntos
Inibidores Enzimáticos/farmacologia , Glicogênio Fosforilase Muscular/antagonistas & inibidores , Compostos Heterocíclicos/síntese química , Compostos Heterocíclicos/farmacologia , Músculo Esquelético/enzimologia , Compostos de Espiro/farmacologia , Xilose/análogos & derivados , Animais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Glicogênio Fosforilase Muscular/metabolismo , Compostos Heterocíclicos/química , Estrutura Molecular , Coelhos , Compostos de Espiro/síntese química , Compostos de Espiro/química , Relação Estrutura-Atividade , Xilose/química , Xilose/farmacologiaRESUMO
The reaction of thiourea with O-perbenzoylated C-(1-bromo-1-deoxy-ß-D-glucopyranosyl)formamide gave the new anomeric spirocycle 1R-1,5-anhydro-D-glucitol-spiro-[1,5]-2-imino-1,3-thiazolidin-4-one. Acylation and sulfonylation with the corresponding acyl chlorides (RCOCl or RSO2Cl where R=tBu, Ph, 4-Me-C6H4, 1- and 2-naphthyl) produced the corresponding 2-acylimino- and 2-sulfonylimino-thiazolidinones, respectively. Alkylation by MeI, allyl-bromide and BnBr produced mixtures of the respective N-alkylimino- and N,N'-dialkyl-imino-thiazolidinones, while reactions with 1,2-dibromoethane and 1,3-dibromopropane furnished spirocyclic 5,6-dihydro-imidazo[2,1-b]thiazolidin-3-one and 6,7-dihydro-5H-thiazolidino[3,2-a]pyrimidin-3-one, respectively. Removal of the O-benzoyl protecting groups by the Zemplén protocol led to test compounds most of which proved micromolar inhibitors of rabbit muscle glycogen phosphorylase b (RMGPb). Best inhibitors were the 2-benzoylimino- (Ki=9µM) and the 2-naphthoylimino-thiazolidinones (Ki=10 µM). Crystallographic studies of the unsubstituted spiro-thiazolidinone and the above most efficient inhibitors in complex with RMGPb confirmed the preference and inhibitory effect that aromatic (and especially 2-naphthyl) derivatives show for the catalytic site promoting the inactive conformation of the enzyme.
Assuntos
Inibidores Enzimáticos/síntese química , Glicogênio Fosforilase Muscular/antagonistas & inibidores , Monossacarídeos/química , Compostos de Espiro/química , Tiazolidinas/química , Animais , Sítios de Ligação , Domínio Catalítico , Cristalografia por Raios X , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Glicogênio Fosforilase Muscular/metabolismo , Cinética , Conformação Molecular , Simulação de Dinâmica Molecular , Propano/análogos & derivados , Propano/química , Ligação Proteica , Coelhos , Relação Estrutura-Atividade , Tiazolidinas/síntese química , Tiazolidinas/metabolismoRESUMO
O-Perbenzoylated 5-(ß-D-glucopyranosyl)tetrazole was reacted with N-benzyl carboximidoyl chlorides to give the corresponding 4-benzyl-3-(ß-D-glucopyranosyl)-5-substituted-1,2,4-triazoles. Removal of the O-benzoyl and N-benzyl protecting groups by base catalysed transesterification and catalytic hydrogenation, respectively, furnished a series of 3-(ß-D-glucopyranosyl)-5-substituted-1,2,4-triazoles with aliphatic, mono- and bicyclic aromatic, and heterocyclic substituents in the 5-position. Enzyme kinetic studies revealed these compounds to inhibit rabbit muscle glycogen phosphorylase b: best inhibitors were the 5-(4-aminophenyl)- (Ki 0.67 µM) and the 5-(2-naphthyl)-substituted (Ki 0.41 µM) derivatives. This study uncovered the C-glucopyranosyl-1,2,4-triazoles as a novel skeleton for nanomolar inhibition of glycogen phosphorylase.
Assuntos
Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Glicogênio Fosforilase/antagonistas & inibidores , Triazóis/síntese química , Triazóis/farmacologia , Cristalografia por Raios X , Inibidores Enzimáticos/química , Esterificação , Glicogênio Fosforilase/metabolismo , Cinética , Espectroscopia de Ressonância Magnética , Triazóis/químicaRESUMO
O-Peracetylated or -perbenzoylated C-(1-bromo-1-deoxy-D-glycopyranosyl)formamides of D-gluco, D-galacto, and D-arabino configuration were reacted with Ag(I)-salts or HgO in nitrile solvents to give N-acyl-1-cyano-D-glycopyranosylamines with an axial C-N bond at the anomeric centre. In the presence of HgBr(2), Hg(CN)(2), or InCl(3) the anomer of the above glycosylamine with an equatorial C-N bond was also isolated or detected. In CH(3)NO(2) solutions as few as 5-10 equiv of the nitrile were sufficient to get acceptable yields for the products. Under similar conditions N-substituted C-(2,3,4,6-tetra-O-acetyl-1-bromo-1-deoxy-ß-D-galactopyranosyl)formamides gave anomeric spiro-oxazoline derivatives which, upon mild acidic hydrolysis, opened up to di- and tripeptides of anomeric α-amino acids.
Assuntos
Aminoácidos/química , Formamidas/química , Oligopeptídeos/química , Oligopeptídeos/síntese química , EstereoisomerismoRESUMO
The major role of liver glycogen is to supply glucose to the circulation in order to maintain normal blood glucose levels. In the muscle and liver, the accumulation and breakdown of glycogen are regulated by the reciprocal activities of glycogen phosphorylase and glycogen synthase. Glycogen phosphorylase catalyses the key step of glycogen degradation and its activity is inhibited by glucose and its analogues. Thus, any readily accessible inhibitor of glycogen phosphorylase may serve as a potential therapy for non-insulin-dependent or type 2 diabetes. Hepatic glycogen phosphorylase has been identified as a novel target for drugs that control blood glucose concentration. Glucopyranosylidene-spiro-thiohydantoin (TH) was found to be one of the most potent glucose derivates, inhibiting the catalytic activity of both muscle and liver glycogen phosphorylase. Here, we demonstrated the co-ordinated regulation of glycogen phosphorylase and synthase by 50 µM TH in liver extracts of Wistar rats, resulting in the activation of synthase by a shortening of the latency compared to control animals. TH was also effective in lowering blood glucose levels and restoring hepatic glycogen content in streptozotocin-induced diabetic rats. Furthermore, intravenous administration of TH to Zucker diabetic fatty rats significantly decreased hepatic glycogen phosphorylase a levels, and the activation of synthase was initiated without any delay.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Glicogênio/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Monossacarídeos/farmacologia , Obesidade/metabolismo , Compostos de Espiro/farmacologia , Animais , Glicemia/efeitos dos fármacos , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/complicações , Ativação Enzimática/efeitos dos fármacos , Glicogênio Fosforilase/metabolismo , Glicogênio Sintase/metabolismo , Injeções Intravenosas , Fígado/enzimologia , Masculino , Monossacarídeos/administração & dosagem , Obesidade/sangue , Obesidade/complicações , Fosforilação/efeitos dos fármacos , Ratos , Ratos Wistar , Ratos Zucker , Compostos de Espiro/administração & dosagemRESUMO
A series of N-(beta-D-glucopyranosyl)amides 5d-i were synthesized by PMe(3) mediated Staudinger reaction of O-peracetylated beta-D-glucopyranosyl azide (1) followed by acylation with carboxylic acids 3d-i and subsequent Zemplén deacetylation. The new compounds were tested for their inhibitory activity against rabbit muscle glycogen phosphorylase and the structure-activity relationships of these compounds are also discussed in this paper.
Assuntos
Amidas/química , Amidas/farmacologia , Dioxanos/química , Dioxanos/farmacologia , Glicogênio Fosforilase Muscular/antagonistas & inibidores , Glicogênio Fosforilase Muscular/metabolismo , Amidas/síntese química , Animais , Dioxanos/síntese química , Estrutura Molecular , Coelhos , Relação Estrutura-AtividadeRESUMO
Glucopyranosylidene-spiro-1,4,2-oxathiazoles were prepared in high yields by NBS-mediated spiro-cyclization of the corresponding glucosyl-hydroximothioates. In an effort to synthesize analogous glucopyranosylidene-spiro-1,2,4-oxadiazolines, with a nitrogen atom instead of the sulphur, attempted cyclizations resulted in aromatization of the heterocycle with opening of the pyranosyl ring. Enzymatic measurements showed that some of the glucose-based inhibitors were active in the micromolar range. The 2-naphthyl-substituted 1,4,2-oxathiazole displayed the best inhibition against RMGPb (K(i)=160 nM), among glucose-based inhibitors known to date.
Assuntos
Glucose/análogos & derivados , Glicogênio Fosforilase Muscular/antagonistas & inibidores , Glicogênio Fosforilase Muscular/metabolismo , Tiazóis/síntese química , Tiazóis/farmacologia , Animais , Glucose/síntese química , Glucose/química , Glucose/farmacologia , Estrutura Molecular , Coelhos , Relação Estrutura-Atividade , Tiazóis/químicaRESUMO
(O-Peracylated alpha-D-gluco- and -galacto-hept-2-ulopyranosylbromide)onamides gave the corresponding (alkyl beta-D-glyco-hept-2-ulopyranoside)onamides under Koenigs-Knorr conditions, and similar aryl glycosides were obtained with sodium phenolates; (aryl and hetaryl 2-thio-beta-D-gluco-hept-2-ulopyranoside)onamides were formed with thiophenols in the presence of K(2)CO(3) in acetone, and reactions with aniline in CH(2)Cl(2) furnished (N-phenyl beta-D-glyco-hept-2-ulopyranosylamine)onamides. Some deprotected derivatives of d-gluco configuration obtained by the Zemplén protocol showed no significant inhibition against rabbit muscle glycogen phosphorylase b.
Assuntos
Glicosídeos/síntese química , Cristalografia por Raios X , Glicosídeos/química , Espectroscopia de Ressonância Magnética , Estrutura MolecularRESUMO
O-Peracetylated methyl 3-(d-glycopyranosylthio)propanoates of beta-d-gluco, and alpha- and beta-d-galacto configurations were oxidized to the corresponding S,S-dioxides (sulfones) by Oxone or MCPBA. Oxidation of the beta-D-gluco derivative with H(2)O(2)/Na(2)WO(4) gave the corresponding S-oxide (sulfoxide). DBU-induced elimination of methyl acrylate from the beta-D-gluco and beta-D-galacto configured S,S-dioxides (sulfones) gave O-peracetylated beta-D-glycopyranosyl-1-C-sulfinates which, on treatment with H(2)NOSO(3)H, furnished the corresponding beta-D-glycopyranosyl-1-C-sulfonamides. Radical-mediated bromination of the protected methyl 3-(beta-D-glycopyranosylthio)propanoate S,S-dioxides gave mixtures of 1-C- and 5-C-bromoglycosyl compounds. Similar brominations of the O-peracetylated beta-D-glycopyranosyl-1-C-sulfonamides resulted in the formation of alpha-D-glycopyranosyl bromides and 1-C- and 5-C-bromoglycosyl sulfonamides. A rationale for these observations was proposed. Methyl 3-(beta-D-glucopyranosylthio)propanoate, its S,S-dioxide, and beta-D-glucopyranosyl-1-C-sulfonamide proved inefficient when tested as inhibitors of rabbit muscle glycogen phosphorylase b.
Assuntos
Glicosídeos/síntese química , Piranos/química , Sulfonamidas/síntese química , Animais , Radicais Livres , Glicogênio Fosforilase Muscular/antagonistas & inibidores , Glicosídeos/química , Halogenação , Estrutura Molecular , Coelhos , Sulfonamidas/química , Sulfonamidas/farmacologiaRESUMO
2-Naphthyl-substituted glucopyranosylidene-spiro-oxathiazole prepared following a novel design principle was found to be the best known glucose analogue inhibitor of rabbit muscle glycogen phosphorylase b (K(i) 160 nM).
Assuntos
Química Farmacêutica/métodos , Glucose/análogos & derivados , Glucose/química , Glicogênio Fosforilase/antagonistas & inibidores , Hipoglicemiantes/síntese química , Compostos de Espiro/síntese química , Tiazóis/síntese química , Animais , Desenho de Fármacos , Glucose/síntese química , Glucose/farmacologia , Glicogênio/química , Glicogênio Fosforilase/química , Hipoglicemiantes/farmacologia , Cinética , Modelos Químicos , Coelhos , Compostos de Espiro/farmacologia , Tiazóis/farmacologiaRESUMO
Preparation of O-peracetylated N-beta-d-glucopyranosyl-N'-acyl urea derivatives resulted in the formation of anomeric mixtures under the following conditions: acylation of O-peracetylated beta-d-glucopyranosyl urea by acyl chlorides in the presence of ZnCl(2) in refluxing CHCl(3); addition of O-peracetylated beta-d-glucopyranosylamine to acyl isocyanates in acetonitrile at rt; addition of carboxamides to in situ prepared O-peracetylated beta-d-glucopyranosyl isocyanate in refluxing toluene. Deprotection of O-peracetylated N-beta-d-glucopyranosyl-N'-acyl ureas either under base (NaOMe in MeOH at or below rt) or under acid (KHSO(4) or AcCl in MeOH at rt) catalyzed transesterification conditions resulted in unavoidable partial cleavage of the N'-acyl moieties. Reaction of beta-d-glucopyranosylammonium carbamate with an isocyanate, isothiocyanate or isoselenocyanate in dry pyridine at rt appears as a general method for the preparation of the corresponding beta-d-glucopyranosyl ureas, -thio- and -selenoureas, respectively, inclusive N'-acyl derivatives.