Showing papers in "Tetrahedron in 1999"

TL;DR: In this paper, 1,3-diarylimidazolinium chlorides were obtained in a three-step sequence via the diimines and ethylene diamine dihydrochlorides.

TL;DR: Indium-Mediated Barbier-type reactions as discussed by the authors have been used for a variety of purposes, such as the synthesis of sialic acids and carbohydrate homologations.

TL;DR: In this paper, 4,6-dimethoxy-1, 3,5-triazin-2(1H)-one was obtained by esterification of caiboxylic acids with DMTMM in methanol, ethanol, isopropy1 alcohol, or t-butyl alcohol.

TL;DR: A review of the up-to-date experiments in phase transfer catalysis can be found in this article, with a focus on the solvent-free conditions of the phase transfer process and its application in organic synthesis.

TL;DR: In this article, high yielding and highly diastereoselective methods for 1,2-additions of organometallic reagents to N-tert-butanesulfinyl aldimines (2) and Ntertbutane sulfinamide products (3) are described.

TL;DR: In this article, a summary of what is known about the steps in a metathesis reaction catalyzed by complexes of the type Mo(CHR′)(NAr)(OR)2, and how the activity and stability of complexes of this type change upon altering each of the ligands in the pseudo-tetrahedral species.

TL;DR: In this paper, the role of CH π interaction in the conformation of organic compounds was examined with the use of the Cambridge Structural Database (CSDB) with the aim to examine the role played by CHπ interaction in organic compounds.

TL;DR: Cell extracts from photoautrophic cultures of two cyanobacterial Calothrix isolates inhibited the growth in vitro of a chloroquine-resistant strain of the malaria parasite, Plasmodium falciparum, and of human HeLa cancer cells, in a dose-dependent manner.

TL;DR: In this paper, free radical chemistry in the synthesis of seven-to-nine-membered rings is presented, and applications of free radical chemiques in the synthesisation of seven to nine-memered rings are discussed.

TL;DR: The compounds present in the caterpillar regurgitates were identified as a structurally diverse group of conjugates of glutamine and glutamic acid linked via an amide bond to saturated and unsaturated C 14 -, C 16 - and C 18 fatty acids.

TL;DR: In this article, a new fluorous tin azide, (C6F13CH2CH2)3SnN3, is reported and this reagent is used to make tetrazoles in both traditional and phase switching modes.

TL;DR: The first total synthesis of a spongipyran macrolide, altohyrtin C, was described in this paper, which relies on a regioselective macrolactonization, a stere-lective Wittig coupling of the two major synthetic fragments, a complex anti-aldol reaction to join the C1-C15 and C16-C28 spiroketal regions, and an anomeric sulfone acylation to join C29-C37 and C38-C43 pyran regions.

TL;DR: In this article, Diels-alder-reaction and opening metathesis polymerization are used for diastereoselective bis-hydroxylation and total synthesis.

TL;DR: In this article, TsCl / Et3N (1.5-2.5 equiv) / cat. Me3N·HCl (0.1-1.0 equiv), KOH [or Ca(OH)2]/Cat.

TL;DR: Five new protease inhibitors, related to aeruginosins 298-A, 98-A and 98-B, were isolated from the cyanobacterium Microcystis aeruginosa and had trypsin, plasmin and thrombin inhibitory activities.

TL;DR: In this article, a stepwise procedure for peptide assembly in which collidine is added to enhance activation and subsequently DIEA is added for coupling was developed, where collidine base collidine enhanced the step involying preactivation of the carboxylic acid residue in contrast to the normal situation in which bases such as NMM or non-hindered pyridine bases inhibit this step.