RESUMO
Codeine N-oxide 2 is an active metabolite of codeine obtained by oxidation and observed as a degradant in codeine drug products such as syrups. Oxidation of codeine's N-methyl function can deliver two regio-isomers due to chirality of the tetra-substituted nitrogen. Hydrogen peroxide oxidation of codeine was performed and induced two different isomers in a 9:1 ratio; these isomers were isolated using preparative high performance liquid chromatography (HPLC) and fully characterized by nuclear magnetic resonance (NMR) techniques. We describe the complete assignment of the minor isomer of codeine N-oxide 3 and attribute a (S) configuration (N-methyl axial) of the tetra-substituted nitrogen. The effects of N-oxidation on the 15 N chemical shifts of the codeine are presented. The 15 N shifts were determined using the CIGAR-HMBC experiment at natural abundance, and the nitrogen resonance of codeine shifted downfield from 42.8 to 118.7 ppm for both N-oxide isomers.
Assuntos
Codeína , Nitrogênio , Isomerismo , Oxirredução , Óxidos , Isótopos de Carbono , Isótopos de NitrogênioRESUMO
We demonstrate here, for the first time, formation of injectable dynamic covalent hydrogels at physiological pH using benzoxaborin-saccharide complexation as a reversible cross-linking method. The gels were prepared by simply mixing hyaluronic acid modified with an original boronic acid derivative, 3,4-dihydro-2H-benzo[e][1,2]oxaborinin-2-ol (1,2-ABORIN), and HA functionalized with 1-amino-1-deoxy-d-fructose. Dynamic rheological experiments confirmed the gel-like behavior (storage modulus (G') > loss modulus (Gâ³) in the frequency window explored) for the designed HA-1,2-ABORIN/HA-fructose network. Furthermore, this hydrogel exhibited excellent self-healing and injectability behaviors in aqueous conditions and was found to be responsive to pH. Additionally, fibroblast cells encapsulated in the HA network showed high viability (>80% after 7 days of cell culture), as monitored by Live/Dead staining. Taken together, this new class of boronate ester cross-linked hydrogel provides promising future for diverse biomedical applications.
Assuntos
Técnicas de Cultura de Células/métodos , Ácido Hialurônico/química , Hidrogéis/química , Animais , Ácidos Borínicos/química , Ácidos Borônicos/química , Técnicas de Cultura de Células/instrumentação , Sobrevivência Celular , Fibroblastos/citologia , Frutose/química , Concentração de Íons de Hidrogênio , Injeções , Espectroscopia de Ressonância Magnética , Camundongos , ReologiaRESUMO
Dynamic covalent hydrogels crosslinked by boronate ester bonds are promising materials for biomedical applications. However, little is known about the impact of the crosslink structure on the mechanical behaviour of the resulting network. Herein, we provide a mechanistic study on boronate ester crosslinking upon mixing hyaluronic acid (HA) backbones modified, on the one hand, with two different arylboronic acids, and on the other hand, with three different saccharide units. Combining rheology, NMR and computational analysis, we demonstrate that carefully selecting the arylboronic-polyol couple allows for tuning the thermodynamics and molecular exchange kinetics of the boronate ester bond, thereby controlling the rheological properties of the gel. In particular, we report the formation of "strong" gels (i.e. featuring slow relaxation dynamics) through the formation of original complex structures (tridentate or bidentate complexes). These findings offer new prospects for the rational design of hydrogel scaffolds with tailored mechanical response.
Assuntos
Ácidos Borônicos/química , Ácido Hialurônico/química , Hidrogéis/química , Concentração de Íons de Hidrogênio , Ressonância Magnética Nuclear Biomolecular , ReologiaRESUMO
Targeting the TNFα pathway is a validated approach to the treatment of psoriasis. In this pathway, TACE stands out as a druggable target and has been the focus of in-house research programs. In this article, we present the discovery of clinical candidate 26a. Starting from hits plagued with poor solubility or genotoxicity, 26a was identified through thorough multiparameter optimisation. Showing robust in vivo activity in an oxazolone-mediated inflammation model, the compound was selected for development. Following a polymorph screen, the hydrochloride salt was selected and the synthesis was efficiently developed to yield the API in 47% overall yield.
Assuntos
Proteína ADAM17/antagonistas & inibidores , Inibidores Enzimáticos/química , Proteína ADAM17/metabolismo , Administração Tópica , Animais , Desenho de Fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/uso terapêutico , Feminino , Humanos , Ácidos Hidroxâmicos/química , Camundongos , Camundongos Pelados , Microssomos Hepáticos/metabolismo , Oxazolona/toxicidade , Psoríase/tratamento farmacológico , Psoríase/patologia , Dermatopatias/induzido quimicamente , Dermatopatias/prevenção & controle , Dermatopatias/veterinária , Solubilidade , Sulfonamidas/síntese química , Sulfonamidas/química , Sulfonamidas/uso terapêutico , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Tetralysal® is a Galderma oral drug product (DP) marketed for the treatment of acne. Tetralysal® is sold in capsules containing either 150â¯mg or 300â¯mg of the drug substance. In the British Pharmacopoeia monograph for Lymecycline Capsules, the impurities already specified in the drug substance (A-G), visible in the European Pharmacopoeia ã1654ã, are also specified together with an unidentified impurity at RRT 1.6 (Impurity J). Based on both monographs Galderma has focused on characterizing most of specified and unspecified impurities to better understand the stability and degradation processes of the formulation. In this manuscript, through both formal synthesis, preparative LCMS and formal degradation studies, we are the first group to confirm the structural identities of 5 unidentified impurities (Impurity J (RRT 1.6), RRT 2.2, 2.4, 2.6 and 3.4), conditions which exacerbate the formation of all 5 impurities and response factors for RRT 2.2, 2.6 and 3.4.
Assuntos
Contaminação de Medicamentos , Limeciclina , Cromatografia Líquida de Alta PressãoRESUMO
Lymecycline is the drug substance (DS) used in the Galderma drug product Tetralysal® capsules with 7 impurities currently described in the pharmacopeia labelled as A-G. In the current monograph, the structural identity of all impurities except E and F have been formally identified. In this manuscript, through both formal synthesis and preparative chromatography, we are the first group to confirm the structural identity, response factor of Impurity F and conditions which exacerbate the formation of both impurities.
Assuntos
Contaminação de Medicamentos , Limeciclina , Cápsulas , Cromatografia Líquida de Alta Pressão/métodos , Contaminação de Medicamentos/prevenção & controleRESUMO
In hydrogels of cross-linked polysaccharides, the total amount of cross-linker and the degree of cross-linking influence the properties of the hydrogel. The substitution position of the cross-linker on the polysaccharide is another parameter that can influence hydrogel properties; hence methods for detailed structural analysis of the substitution pattern are required. NMR and LC-MS methods were developed to determine the positions and amounts of substitution of 1,4-butanediol diglycidyl ether (BDDE) on hyaluronic acid (HA), and for the first time it is shown that BDDE can react with any of the four available hydroxyl groups of the HA disaccharide repeating unit. This was achieved by studying di-, tetra-, and hexasaccharides obtained from degradation of BDDE cross-linked HA hydrogel by chondroitinase. Furthermore, amount of linker substitution at each position was shown to be dependent on the size of the oligosaccharides. For the disaccharide, substitutions were predominantly at ΔGlcA-OH2 and GlcNAc-OH6 while in the tetra- and hexasaccharides, it was mainly at the reducing end GlcNAc-OH4. In the disaccharide there was no substitution at this position. Since chondroitinase is able to completely hydrolyse non-substituted HA into unsaturated disaccharides, these results indicate that the enzyme is prevented to cleave on the non-reducing side of an oligosaccharide substituted at the reducing end GlcNAc-OH4. The procedure can be adopted for the determination of substitution positions in other types of polymers.
Assuntos
Ácido Hialurônico/química , Hidrogéis/química , Butileno Glicóis/química , Condroitinases e Condroitina Liases/metabolismo , Hidrólise , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Oligossacarídeos/química , Proteus vulgaris/enzimologiaRESUMO
A new synthesis of attenol A is described. Key features of this work include a crucial silicon tether-aided coupling metathesis step and the use of iodoetherification as an efficient protection method for 1,5-ene-ols. [reaction: see text]
Assuntos
Éteres Cíclicos/síntese química , Silício , Animais , Antineoplásicos/síntese química , Antineoplásicos/toxicidade , Catálise , Sobrevivência Celular/efeitos dos fármacos , Éteres Cíclicos/toxicidade , Estrutura MolecularRESUMO
Monodentate phosphoramidites have been used for the first time as chiral ligands in the Rh-catalyzed enantioselective conjugate addition of arylboronic acids to enones, unsaturated esters, lactones, and nitro alkenes. High reaction rates and ee's up to 89% have been obtained.
RESUMO
A very fast reaction and enantioselectivities >98% have been reached in the rhodium-catalyzed arylboronic acid addition to enones using a monodentate phosphoramidite ligand. Temperature-dependent studies show that monodentate phosphoramidites form stable complexes with metals and can induce high enantioselectivities even at high temperatures in polar solvents.
RESUMO
The preparation of a series of new fumagillin-derived MetAP-2 inhibitors is described. The synthetic approach was designed so as to permit modification of the fumagillin backbone at sites inaccessible through semisynthesis or previously existing total syntheses. An Evans aldolization and a ring-closing metathesis allowed the preparation of a pivotal intermediate which could then be functionalized in various ways using already established or newly developed methodologies.
Assuntos
Aminopeptidases/antagonistas & inibidores , Inibidores da Angiogênese/química , Ácidos Graxos Insaturados/química , Metaloendopeptidases/antagonistas & inibidores , Inibidores da Angiogênese/farmacologia , Cicloexanos , Espectroscopia de Ressonância Magnética , Modelos Moleculares , SesquiterpenosRESUMO
The use of phosphoramidite ligands in the rhodium-catalyzed asymmetric conjugate addition of potassium organotrifluoroborates to various enones in the absence of water is described. A systematic search for effective catalysts has been performed by use of high-throughput screening methods. Initially, we have screened reaction conditions, catalyst precursors, and focused ligand libraries. In the next stage we have used the monodentate ligand combination approach, and finally we have made a library of 96 different phosphoramidites by parallel synthesis in the robot (instant ligand libraries) and have tested these in the vinylation of cyclohexenone (up to 88% enantiomeric excess, ee) and 4-phenyl-3-buten-2-one (up to 42% ee). Arylation of cyclohexenone by use of potassium phenyltrifluoroborate gave 3-phenylcyclohexanone with 99% ee.