1,720,974 research outputs found
Effects of mono-, di- and tri-hydroxybenzoic acids on the nitrosation of propranolol: structure-activity relationship
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Amine Exchange and Unexpected Ring Opening Reaction on Pyranone Derivatives : Synthesis of 3-Amino-Substituted Oxonaphthopyrancarbaldehydes and Tetrahydropyrimidinethanones as New Potential Oligonucleotide Stabilization Agents
No full textSimultaneous HPLC determination of multiple components in a commercial cosmetic cream.
No full textA high-performance liquid chromatographic method for the simultaneous determination of magnesium ascorbyl phosphate (I), imidazolidinylurea (II), a mixture of methyl-(III), ethyl-(IV), propyl-(V), butyl-(VI) parabens dissolved in phenoxyethanol, and ascorbyl palmitate (VII), was studied by using a cyano-propyl column and a methanol gradient at 220 and 240 nm. Calibration curves were found to be linear in the 0.05-5 mg ml(-1) range (compounds I, II, VII) and 0.9-160 mg ml(-1) (compounds III-VI). Linear regression analysis of the data demonstrates the efficacy of the method in terms of precision and accuracy. An extraction method is developed and validated in order to apply this chromatographic method to a commercial cosmetic cream. The precision of this method, calculated as the relative standard deviation (RSD) of the recoveries (1.57-2.21%) was excellent for all compounds I-VII
[Chemistry and pharmacology of pyrane derivatives. XVII. Synthesis of substituted 2-(dialkylamino)-3-formylchromones and their tricyclic derivatives].
No full textSubstituted 2-(dialkylamino)-3-formylchromones (II) were obtained from the reaction of substituted 2-(dialkylamino)chromones (I) either with the N,N-dimethylformamide-POCl3 reagent [compounds (IIa-e)] or with dichloromethylmethylether in the presence of TiCl4 [compounds (IIf-i)]. By treating (IIa,f) with hydroxylamine the oximes (IIIa,f) were prepared, which in turn were converted into the nitriles (IVa,f) by treatment with acetic anhydride. Compound (IIa), selected for the smallest steric hindrance of the 2-dialkylamino substituent, by reaction with hydrazines afforded [1]benzopyrano [2,3-c]pyrazole derivatives (VI), whereas reaction of (IIa) with guanidine, benzamidine or S-methylisothiourea gave rise to the formation of 5H-[1]benzopyrano[2,3-d]pyrimidine derivatives (IX). Among the compounds tested for their antiallergic properties, (IIf) showed an appreciable activity, but also high toxicity
Delayed neutrophil apoptosis induced by synovial fluid in rheumatoid arthritis: role of cytokines, estrogens, and adenosine.
No full textSynthesis of ionones and carvone analogues: Olfactory properties and preliminary toxicity assays
No full text[Chemistry and pharmacology of pyran derivatives. 16. Derivatives of 2-(dialkylamino)-7-methoxychromone with antiallergic activity].
No full textThe title compds. I (NRR1 = NEt2, NMe2, pyrrolidino, NHEt, NAcEt; R2 = H, Cl, NO2) and II [X = HOCH(CH2)2, (CH2)3, (CH2)5] were prepd. from I (R2 = H). I and II have antiallergic activity, I (R = R2 = H, R1 = Et) giving 92% protection at 500 mg/kg orally in the passive cutaneous anaphylaxis test
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