19 research outputs found
Influence of secondary ligand on structures and topologies of lanthanide coordination polymers with 1,3,5-triazine-2,4,6-triamine hexaacetic acid
© 2015 Taylor and Francis. A series of new lanthanide coordination polymers has been synthesized and structurally characterized; [Ln 4 (TTHA) 2 (pzac)(H 3 O) 2 (H 2 O)]·5H 2 O (Ln = Pr (1a) and Nd (1b)), [Sm 8 (TTHA) 4 (pzac) 0.5 (H 3 O)(H 2 O) 7.5 ]·4H 2 O (2), [Ln 4 (HTTHA) 2 (SO 4 )(H 2 O) 4 ]·5H 2 O (Ln = Pr (3a) and Nd (3b)), where H 6 TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetic acid, and H 2 pzac = 2,5-dioxo-piperazine-1,4-diacetic acid. The compounds feature 3-D frameworks comprising the deprotonated H 6 TTHA as the primary ligand and either the in situ generated pzac 2- or sulfate as the secondary ligands. The influence of the deprotonated H 6 TTHA in directing the framework structures through preferential coordination modes and molecular conformation is described. The effect of the secondary ligands in increasing the compactness of the frameworks and in the alternation of the framework topologies based on the four-connected pts type is described
Ph<sub>3</sub>P/I<sub>2</sub>‑Mediated Synthesis of <i>N,N</i>′<i>,N</i>″‑Substituted Guanidines and 2‑Iminoimidazolin-4-ones from Aryl Isothiocyanates
A convenient one-pot
procedure for the synthesis of acyclic and
cyclic guanidines mediated by the Ph<sub>3</sub>P/I<sub>2</sub> system
is described. Sequential condensation of aryl isothiocyanates with
amines followed by dehydrosulfurization and guanylation could lead
to both symmetric and unsymmetric <i>N,N</i>′<i>,N</i>″-substituted derivatives. Through a tandem guanylation–cyclization,
a series of 2-iminoimidazolin-4-ones could also be prepared in good
yields from the reaction of aryl isothiocyanates with amino acid methyl
esters
Application of <i>N</i>‑Acylbenzotriazoles in the Synthesis of 5‑Substituted 2‑Ethoxy-1,3,4-oxadiazoles as Building Blocks toward 3,5-Disubstituted 1,3,4-Oxadiazol-2(3<i>H</i>)‑ones
5-Substituted-2-ethoxy-1,3,4-oxadiazoles
were conveniently prepared
through a one-pot sequential <i>N</i>-acylation/dehydrative
cyclization between ethyl carbazate and <i>N</i>-acylbenzotriazoles
in the presence of Ph<sub>3</sub>P–I<sub>2</sub> as a dehydrating
agent. Subsequent treatment with a stoichiometric amount of alkyl
halides (X = Cl, Br, I) enables a rapid access to a variety of 3,5-disubstituted
1,3,4-oxadiazol-2Â(3<i>H</i>)-ones in good to excellent yields
Approach to the Synthesis of 2,3-Disubstituted‑3<i>H</i>‑quinazolin-4-ones Mediated by Ph<sub>3</sub>P–I<sub>2</sub>
Readily
available <i>N</i>-substituted amides or their
requisite carboxylic acids or acid chlorides have been used to construct
2,3-disubstituted-3<i>H</i>-quinazolin-4-ones in a one-pot
procedure. Key transformation in this convergent approach involves
Ph<sub>3</sub>P–I<sub>2</sub>-mediated formation of amidine
upon condensation of an amide or the intermediate amide with methyl
anthranilate. Cyclization of the amidine-tethered anthranilate then
affords 2,3-disubstituted-3<i>H</i>-quinazolin-4-ones in
good to excellent yields under mild conditions
Highly diastereoselective synthesis of enantioenriched anti-α-allyl-β-fluoroamines
A highly diastereoselective synthesis ofanti-a-allyl-b-fluoroamineshas been developed involving enantioselectivea-fluorination ofaldehydes followed by a diastereoselective Petasis allyl borono-Mannich reaction. The products are obtained generally in goodoverall yields for the two steps and with drs of 97 : 3-99 : 1 and eesof 86-92%. Selected products were converted to 3-, 5- and6-membered ring heterocycles, the latter two types incorporatingan exo-cyclic fluorine
Immunochromatographic Strip Test for Rapid Detection of Nevirapine in Plasma Samples from Human Immunodeficiency Virus-Infected Patientsâ–ż
We report a novel one-step immunochromatographic strip test for the rapid, qualitative detection of nevirapine in plasma samples from human immunodeficiency virus-infected patients. The sensitivity was 100% (95% confidence interval [95% CI], 97.8 to 100%), and the specificity was 99.5% (95% CI, 97.2 to 99.9%). The limit of detection was 25 ng/ml. Immunochromatographic strip tests are simple, rapid, and cheap assays that could greatly facilitate drug level monitoring in resource-limited settings
Ultrasound-Assisted Solvent-Free Parallel Synthesis of 3‑Arylcoumarins Using <i>N</i>‑Acylbenzotriazoles
An ultrasound-assisted
one-pot acylation/cyclization reaction between <i>N</i>-acylbenzotriazoles
and 2-hydroxybenzaldehydes has been
developed for the synthesis of substituted 3-arylcoumarins. Using
ultrasound not only allows rapid and clean conversion but also simplifies
experimental setup and parallel workup leading to rapid generation
of 3-arylcoumarin libraries under mild, solvent-free, and chromatography-free
conditions