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General Protocol (general + protocol)
Selected AbstractsGeneral Protocols for the Synthesis of C2 -Symmetric and Asymmetric 2,8-Disubstituted Analogues of Troeger,s Base via Efficient Bromine,Lithium Exchanges of 2,8-Dibromo-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine.CHEMINFORM, Issue 5 2003Jacob Jensen Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Facile and Efficient One-Pot Synthesis of Substituted Quinolines from ,-Arylamino Ketones Under Vilsmeier ConditionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2009Yan Wang Abstract An efficient one-pot synthesis of substituted quinolines from ,-arylamino ketones in the presence of PBr3 in DMF has been developed. This general protocol provides a novel and facile access to substituted quinolines by sequential Vilsmeier,Haack reaction, intramolecular cyclization and aromatization reactions of ,-arylamino ketones. PBr3 plays a dual role in the quinoline synthesis: as a key component of the Vilsmeier reagent (PBr3/DMF) and as a reducing reagent. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Indole-Diterpene Synthetic Studies: Total Synthesis of (,)-21-IsopentenylpaxillineHELVETICA CHIMICA ACTA, Issue 12 2003An efficient, stereocontrolled total synthesis of the complex indole-diterpene alkaloid (,)-21-isopentenylpaxilline (1) has been achieved. Key elements of the synthesis include the stereocontrolled construction of the advanced eastern hemisphere (,)- 68, involving a highly efficient union of the eastern and western fragments (,)- 68 and 5 exploiting our 2-substituted indole synthesis, application of the Negishi, cycloalkylation tactic as a new, potentially general protocol for the construction of ring C, and the fragmentation of a ,,, -epoxy ketone to introduce the tertiary OH group at C(13) in the indole diterpene skeleton. [source] Endoscopic fibrin sealing of gastrocutaneous fistulas after sleeve gastrectomy and biliopancreatic diversion with duodenal switchJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 12 2008Theodossis S Papavramidis Abstract Background and Aim:, Gastrocutaneous fistulas (GCF) are uncommon complications accounting for 0.5,3.9% of gastric operations. When their management is not effective, the mortality rate is high. This study reports the conservative treatment of GCF in morbidly obese patients who underwent biliopancreatic diversion with duodenal switch. Methods:, Ninety-six morbidly obese patients were treated in our department with biliopancreatic diversion with duodenal switch (Marceau technique) and, in six of them, a high-output GCF developed. A general protocol was applied to all patients presenting a GCF. Everyone was treated by total parenteral nutrition (TPN) and somatostatin for at least 7 days after the appearance of the leak. If the leak continued, then fibrin glue was used as a tissue adhesive. Endoscopic application of the sealant was accomplished under direct vision via a double-lumen catheter passed through a forward-viewing gastroscope. Results:, All patients were treated successfully with conservative treatment (either solely with TPN and somatostatin, or with endoscopic fibrin sealing sessions). No evidence of fistula was observed at gastroscopy 3 and 24 months after therapy. Conclusion:, The conservative treatment of GCF following biliopancreatic diversion with duodenal switch is highly effective. All patients should enter a protocol that includes TPN and somatostatin. When the GCF persist, endoscopic sealing glue should be considered before operation because it is simple, safe, effective and, in some cases, life-saving. Therefore, conservative treatment should be employed as a therapeutic option in GCF developing after bariatric surgery. [source] Ionic liquid catalyzed expeditious synthesis of 2-aryl-2,3-dihydroquinolin-4(1H)-ones and 2-aryl-2,3-dihydro-4H -chromen-4-ones under microwave irradiationJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2009Dalip Kumar A facile and convenient synthesis of 2-aryl-2,3-dihydroquinolin-4(1H)-one and 2-aryl-2,3-dihydro-4H -chromen-4-one has been described using ionic liquid catalyzed intramolecular cyclization of the corresponding 2,-aminochalcones and 2,-hydroxychalcones, respectively. The rapid and fairly general protocol affords product in good yield. Ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, was recovered and reused without loosing its efficiency. J. Heterocyclic Chem., (2009) [source] FRET-Based Direct and Continuous Monitoring of Human Fucosyltransferases Activity: An Efficient synthesis of Versatile GDP- L -Fucose Derivatives from Abundant d- Galactose,CHEMISTRY - A EUROPEAN JOURNAL, Issue 2 2008Takahiro Maeda Abstract We have developed a facile and versatile protocol for the continuous monitoring of human fucosyltransferases activity by using fluorescence energy resonance transfer (FRET), and have explored the feasibility of its use in an inhibitor screening assay. A convenient sugar nucleotide with a fluorogenic probe, 6-deoxy-6- N -(2-naphalene-2-yl-acetamide)-,- L -galactopyranos-1-yl-guanosine 5,-diphosphate disodium salt (1), was efficiently synthesized from naturally abundant D -galactopyranose via a key intermediate, 6-azide-1,2,3,4-tetra- O -benzoyl-6-deoxy-,- L -galactopyranose (10). It was demonstrated that the combined use of the glycosyl donor 1 and a dansylated acceptor substrate, sialyl-,2,3-LacNAc derivative (2) allowed us to carry out highly sensitive, direct, and continuous in vitro monitoring of the generation of sialyl Lewis,X (SLex), which is catalyzed by human ,-1,3-fucosyltransferase,VI (FUT-VI). A kinetic analysis revealed that compound 1 was an excellent donor substrate (KM=0.94,,M and Vmax=0.14,,M,min,1) for detecting human FUT-VI activity. To the best of our knowledge, this synthetic fluorogenic probe is the most sensitive and selective donor substrate for FUT-VI among all of the known GDP-Fuc analogues, including the parent GDP-Fuc. When a dansylated asparagine-linked glycopeptide 20, which is derived from egg yolk was employed as an alternate acceptor substrate, a FRET-based assay with compound 1 could be used to directly monitor the ,1,6-fucosylation at the reducing terminal GlcNAc residue by human FUT-VIII (KM=175,,M and Vmax=0.06,,M/,min); this indicates that the present method might become a general protocol for the characterization of various mammalian fucosyltransferases in the presence of designated fluorogenic acceptor substrates. The present protocol revealed that compound 23, which was obtained by a 1,3-dipolar cycloaddition between the disodium salt 16 and 1-ethynyl-naphthalene exhibits highly potent inhibitory effects against the FUT-VI-mediated sialyl Lewis,X synthesis (IC50=5.4,,M). [source] | ||||||||||||||||||||||