- Oxa/thiazole-tetrahydropyran triazole-linked hybrids with selective antiproliferative activity against human tumour cells
-
Inspired by diverse marine bioactive compounds, the principle of molecular hybridization was applied to produce a series of new compounds combining diverse heterocyclic systems (oxa/thiazoles and tetrahydropyrans) via a triazole ring, attempting to increase the activity of individual building blocks. These new compounds exhibit a highly interesting antiproliferative activity against different human tumour cells and good selectivity when compared to normal cells. The formation of reactive oxygen species and the interaction with P-gp were also evaluated for the lead compounds.
- Valdomir, Guillermo,Fernández,Lagunes, Irene,Padrón, Juan I.,Martín, Víctor S.,Padrón, José M.,Davyt, Danilo
-
-
Read Online
- Perfluoroalkylated Calix[4]pyrroles: Fluoride Ion Extraction from an Aqueous Medium
-
Octaalkenyl calix[4]pyrrole ((CH2=CH(CH2)2)8C4P) is highly useful for the postfunctionalization of different calix[4]pyrroles with desired functionalities. Functionalization with perfluoroalkyl chains [CF3(CF2)n; Rfn] gave perfluoroalkyl calix[4]pyrroles (Rfn(CH2)4)8C4P; n=6, 8), having >60 % fluorine content, which created a hydrophobic environment inside the calix[4]pyrrole cavity and recognized fluoride and chloride ions in solution as well as in the solid state. The fluoride ion is extracted efficiently from aqueous CsF and TBAF solutions by using (Rf6(CH2)4)8C4P, as droplets. The fluorinated chain generated a hydrophobic environment which broke the hydration shell associated with the anion and separated out fluoride ions as droplets from aqueous medium. Furthermore, the fluoride ions competitively replaced chloride ions from the (Rf6(CH2)4)8C4P cavity.
- Maji, Sinchan,Mandal, Debaprasad
-
-
Read Online
- Synthesis of 1,3-Cycloalkadienes from Cycloalkenes: Unprecedented Reactivity of Oxoammonium Salts
-
Few methods allow for the direct conversion of cycloalkenes into cycloalkadienes with high chemo- and regioselectivity. Herein, we report a convenient one-pot process for this transformation that involves the unprecedented N-preferential group transfer of N-oxoammonium salts to cycloalkenes, followed by Cope elimination, to afford cycloalkadienes at room temperature and pressure.
- Nagasawa, Shota,Sasano, Yusuke,Iwabuchi, Yoshiharu
-
supporting information
p. 13189 - 13194
(2016/10/30)
-
- Dibutyltin oxide mediated diastereoselective cyclodehydration/sulfonylation of 1,2,4-triols
-
Dibutyltin oxide (Bu2SnO) mediated cyclodehydration or sulfonylation of 1,2,4-triols is predictably diastereoselective depending on the steric bulk of the substituents at C4. A larger difference (ΔA-value >1 kcal/mol) leads to the syn-1,2,4-triols favouring cyclodehydration (78-85%) to form 3-hydroxytetrahydrofurans, with the anti-1,2,4-triols favouring monosulfonylation (66-87%). Triols from symmetrical ketones preferentially undergo cyclodehydration in high yield (>75%) due to a gem-disubstituent effect. Thus, the 1,2,4-triols derived from simple cyclic ketones also favour cyclodehydration to form spirocyclic 3-hydroxytetrahydrofurans in 72-79% yields.
- Gamedze, Makhosazana P.,Nkambule, Comfort M.
-
supporting information
p. 1825 - 1829
(2015/03/30)
-
- Synthesis and antiviral evaluation of novel 2′,2′-difluoro 5′-norcarbocyclic phosphonic acid nucleosides as antiviral agents
-
A very efficient synthetic route to novel 2′,2′-difluoro 5′-norcarbocyclic phosphonic acid nucleosides from but-3-en-1-ol 5 is described. The discovery of 2′-fluorinated furanose nucleoside 1 as a potent anti-HIV-1 agent has led to the synthesis and biological evaluation of 2′-modified 5′-norversions of the carbocyclic phosphonate nucleosides. The synthesized nucleoside analogues 18, 19, 23a, 23b, and 24 were tested for anti-HIV activity as well as cytotoxicity. Adenine analogue 19 shows significant anti-HIV-1 activity (EC50 = 13 μM).
- Shen, Guang Huan,Hong, Joon Hee
-
-
- Low catalyst loading in ring-closing metathesis reactions
-
An efficient procedure is described for ring-closing metathesis reactions. A conversion of 95 % for diethyl diallylmalonate in dilute solution could be achieved within a few minutes, reaching TOF=4173min-1, with very low loading of commercially available Ru catalysts that contained unsaturated NHC ligands. In general, only 50 to 250ppm of the catalyst is required to achieve near-quantitative conversion into a broad variety of 5-16-membered heterocyclic compounds. The practicality of this procedure was illustrated in the synthesis of 5-8-membered N-tert-butoxycarbonyl (N-Boc)- and N-para-toluenesulfonyl (N-Ts)-protected cyclic amines and 9-16-membered lactones. The synthesis of macrocyclic proline-based lactams required slightly higher catalyst loadings. Along with monocyclic products, oligomeric byproducts, mostly cyclodimers, were isolated and characterized. Getting some closure: An efficient procedure is described for ring-closing metathesis reactions in which only 50 to 250ppm of catalyst is required to effect almost-quantitative conversion into a broad range of 5-16-membered heterocyclic compounds. The practicality of this procedure was illustrated in the synthesis of 5-8-membered N-protected cyclic amines, 9-16-membered lactones, and 11-16-membered proline-based lactams. Copyright
- Kadyrov, Renat
-
supporting information
p. 1002 - 1012
(2013/02/23)
-
- Dehydrogenation of cyclic thioethers bound to a [Rh(diphosphine)] + fragment
-
The metal-promoted dehydrogenation of cyclic thioethers S(C 5H9)(R) (R = C5H9, Ph) to give the corresponding cycloalkenes, S(C5H7)(R), using the [Rh{Ph2P(CH2)3PPh2}]+ fragment is reported.
- Dallanegra, Romaeo,Pilgrim, Ben S.,Chaplin, Adrian B.,Donohoe, Timothy J.,Weller, Andrew S.
-
supporting information; experimental part
p. 6626 - 6628
(2011/08/10)
-
- Application of stereoselective ether transfer to the synthesis of isotactic polyethers
-
An efficient, convergent synthetic strategy has been developed which enables the synthesis of a series of naturally occurring isotactic polymethoxy compounds. Ether transfer followed by a hydride workup enables simultaneous, diastereoselective production of two methoxy centers in a single step. High yields and diastereoselectivity are observed even in stereochemically rich, polyoxygenated systems. Direct generation of bis-methyl ether moieties from methoxymethyl ethers minimizes the need for typical protective group strategies and the use of expensive methyl transfer reagents. Moreover, the simultaneous generation of a terminal primary iodide serves as a coupling partner for the generation of higher order congeners.
- Liu, Kai,Arico, Joseph W.,Taylor, Richard E.
-
supporting information; experimental part
p. 3953 - 3957
(2010/08/07)
-
- Convenient synthesis of 6,6-bicyclic malonamides: A new class of conformationally preorganized ligands for f-block ion binding
-
A general synthetic approach was developed for the preparation of a series of 6,6-bicyclic malonamides, a class of ligands that provide a preorganized binding site for f-block ions (particularly trivalent lanthanides). The approach described is convenient to introduce a variety of functional groups at the amide nitrogens to tune the properties of the ligand without altering the preorganized binding. Each of the ten derivatives (that represent a range of functionality, including R = alkyl, hydroxy, phenyl, ester, perfluorocarbon) reported here derives from a single, readily prepared dialdehyde intermediate. This intermediate is converted to the final products via reductive amination with an appropriately functionalized benzylamine, followed by hydrogenolysis and lactam formation. Because derivatization occurs late in the synthesis, the approach is general, requiring only modification of the purification procedures for each new derivative. To aid in the purification of the bicyclic malonamides, we report a novel complexation-based purification method that takes advantage of the high affinity of the ligand for f-block metals.
- Parks, Bevin W.,Gilbertson, Robert D.,Domaille, Dylan W.,Hutchison, James E.
-
p. 9622 - 9627
(2007/10/03)
-
- Double ring-closing metathesis reaction of nitrogen-containing tetraenes: Efficient construction of bicyclic alkaloid skeletons and synthetic application to four stereoisomers of lupinine and their derivatives
-
The double ring-closing metathesis reaction of nitrogen-containing tetraenes was studied. The selectivity of the fused/dumbbell-type products can be controlled by the electronic/steric effects of the substituents attached to the C=C bonds and the s-cis/s-trans conformational ratios of the substrates. This methodology has also been successfully applied to the enantioselective synthesis of four stereoisomers of lupinine and their derivatives.
- Ma, Shengming,Ni, Bukuo
-
p. 3286 - 3300
(2007/10/03)
-
- Deprotection of benzyl and p-methoxybenzyl ethers by chlorosulfonyl isocyanate-sodium hydroxide
-
CSI-NaOH procedure provided a new and mild methodology for the deprotection of benzyl and p-methoxybenzyl ethers without affecting the other functional groups under similar reaction conditions.
- Kim, Ji Duck,Han, Gyoonhee,Zee, Ok Pyo,Jung, Young Hoon
-
p. 733 - 735
(2007/10/03)
-
- Indium-mediated consecutive 1,2-shift reaction and regioselective allylation of vinyl epoxides
-
Allyl indium, prepared from allyl bromide and indium metal in aprotic solvent, reacts with terminal vinyl epoxides at room temperature to afford various bishomoallyl alcohols in moderate to high yields via consecutive 1,2-shift reaction and regioselective
- Oh, Byung Kyu,Cha, Joo Hwan,Cho, Yong Seo,Choi, Kyung Il,Koh, Hun Yeong,Chang, Moon Ho,Pae, Ae Nim
-
p. 2911 - 2913
(2007/10/03)
-
- Novel carbonyl allylation mediated by SnCl2/Cu in water
-
Copper metal was found to be able to catalyze SnCl2-mediated coupling between carbonyl compounds and allyl halides to give the corresponding homoallylic alcohols in high yields.
- Tan, Xiang-Hui,Shen, Bo,Liu, Lei,Guo, Qing-Xiang
-
p. 9373 - 9376
(2007/10/03)
-
- Syntheses with Organoboranes. XI. Allylboration of Vinylic Epoxides with Allylic Dialkylboranes
-
equation presented Allylboration of representative vinylic epoxides with allyldiethylborane (1) and (2-cyclohexenyl)dicyclohexylborane (2) affords the corresponding 1,2- and 1,4-addition products. cis-1,2-Addition is favored in the reaction of 1 with 3,4-
- Zaidlewicz, Marek,Krzeminski, Marek P.
-
p. 3897 - 3899
(2007/10/03)
-
- ACTIVATION DU ZINC PAR LE TRIMETHYLCHLOROSILANE: PREPARATION D'ALCOOLS β-ETHYLENIQUES A PARTIR DE BROMURES α-ETHYLENIQUES, DE DERIVES CARBONYLES ET DE ZINC DANS L'ETHER.
-
β-ethylenic alcohols can be prepared in ether from an α-ethylenic bromide, a carbonyl compound and zinc, provided the metal is previously activated by addition of a small amount of trimethylchlorosilane.
- Picotin, G.,Miginiac, Ph.
-
p. 4551 - 4552
(2007/10/02)
-