One Pot Synthesis of Acridine Analogues from 1,2-Diols as Key Reagents

Lead tetraacetate have been demonstrated to be efficient, low cost and mild reagents for the one pot synthesis of acridine derivatives from a variety of 1,2-diols. 1,2-Diols are oxidised in situ to aldehydes, which in turn undergo reaction with dimedone and ammonium acetate to yield acridine derivatives. The attractive features of this process are mild reaction conditions, short reaction times, broad functional group tolerance, easy isolation of products and excellent yields. Thus, the current method utilises 1,2-diols instead of benzaldehydes to synthesise acridines derivatives

One-Pot Synthesis of 2,4,5-Triphenyl Imidazoles from 1,2-Diols as Key Reagents

A simple one-pot procedure for the preparation of 2,4,5-triphenyl imidazole derivatives is presented. The procedure involves the lead tetraacetate oxidation of 1,2-diols to give aldehydes in situ, which then undergo a three-component reaction with benzil and ammonium acetate to yield the imidazole derivatives. © 2017 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinhei

Comparative study of pantoprazole and esomeprazole for erosive gastroesophageal reflux disease: a prospective study

Background: The objective of this study was to compare the efficacy of pantoprazole and esomeprazole to heal and relief from erosive esophagitis (EE) disease related symptoms.Methods: One hundred and ten patients (IIT-patients) with EE were randomized to receive 8 weeks of 40 mg pantoprazole (n=55) twice before food for first 7 days followed by once daily and esomeprazole 40 mg (n=55) once daily. Daily changes in heartburn and reflux were assessed.Results: The mean heartburn score with esomeprazole is more rapidly decreased than with pantoprazole. There no mild significant differences between two groups in the rate healing of reflux esophagitis at week and 4 and 8. The LA grade severity compare with esomeprazole group is rapidly decreased compared with pantoprazole. Esomeprazole 40 mg provided significantly greater healing than pantoprazole 40 mg after 4 weeks of treatment in patients with EE (56.36% vs. 49.09 %). Esomeprazole-treated patients were healed after up to 8 weeks of treatment similar those treated with pantoprazole (94.54% vs. 70.90 %).Conclusion: Esomeprazole is more effective than pantoprazole for rapid relief of heartburn symptoms and acid reflux symptoms in patients with reflux esophagitis

Six-membered ring systems: with O and/or S atoms

A large variety of publications involving O- and S-6-membered ring systems have appeared in 2017. The importance of these heterocyclic compounds is highlighted by the huge number of publications on the total synthesis of natural oxygen derivatives and of other communications dedicated to synthetic derivatives. Reviews on stereoselective organocatalytic synthesis of tetrahydropyrans (17EJO4666), of tetrahydropyrans and their application in total synthesis of natural products (17CSR1661), on the synthesis of the less thermodynamically stable 2,6-trans-tetrahydropyrans (17S4899), on enantioselective synthesis of polyfunctionalized pyran and chromene derivatives (17TA1462), and on enantioselective and racemic total synthesis of camptothecins, including the formation of their pyran-2-one ring (17SL1134), have appeared. Advances in the transition metal-catalyzed synthesis of pyran-2/4-ones (17TL263), N-heterocyclic carbene (NHC)-catalyzed achiral synthesis of pyran-2-one, coumarin and (thio)chromone derivatives (17OBC4731), on the synthesis and transformation of 2H-pyran-2-ones (17T2529) and 2-styrylchromones (17EJO3115) into other heterocyclic compounds, have been surveyed. The strategies to build up the tetrahydropyranyl core of brevisamide (17H(95)81) and the reactions of ketyl radicals, generated from carbonyl derivatives under transition-metal photoredox-catalyzed conditions, leading to isochromen- and chroman-type compounds (17CC13093) were disclosed. Developments in the synthesis of pentafluorosulfanyl(chromene and coumarin) derivatives (17TL4803), photoswitchable D9-tetrahydrocannabinol derivatives (17JA18206), and aminobenzopyranoxanthenes with nitrogen-containing rings (17JOC13626) have been studied.info:eu-repo/semantics/publishedVersio

Biginelli reaction of vicinal diols: A new route for one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives

Background: 3,4-Dihydropyrimidin-2(1H)-one derivatives are an important class of nitrogen heterocycles. These compounds present a wide range of biological activities viz antibacterial, antifungal, and antidiabetic. Although many synthetic methods are available in the literature for the synthesis of these molecules, many of these methods have their own limitations such as use of excess of expensive catalyst and poor yields. Methods: The synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives is developed through the reaction of 1,2-diols, ethyl acetoacetate and urea in the presence of lead tetraacetate in dry ethanol under reflux conditions. Results: A series of 3,4-dihydropyrimidin-2(1H)-one derivatives were synthesized in good yields (82-95) under reflux for 2-3.5 hours in ethanol solvent. The structural assignments of these compounds were made on the basis of elemental analysis and spectroscopic data. Conclusion: This protocol is an alternative to existing procedure for the synthesis of Biginelli compounds. The present methodology reduces the number of steps in total synthesis. © 2017 Bentham Science Publishers

Pseudo Multicomponent Reaction: Synthesis of Fused Pyrano Biscoumarin Analogs from 1,2-diols

A simple and efficient method has been developed for the synthesis of fused pyrano biscoumarins using lead tetraacetate as an oxidizing agent by the condensation of one equivalent of 1,2-diols and four equivalent of 4-hydroxy coumarin in acetonitrile as solvent at 80°C with good to excellent yields. © 2016 Wiley Periodicals, Inc