Click chemistry for [(99m)Tc(CO)(3)] labeling of Lys(3)-bombesin.

(99m)Tc-HYNIC labeled Lys(3)-bombesin has shown specific binding to gastrin-releasing peptide receptors (GRP-r) over-expressed in cancer cells. Click chemistry offers an innovative functionalization strategy for biomolecules such as bombesin. The aim of this research was to apply a click chemistry approach for [(99m)Tc(CO)(3)] labeling of Lys(3)-bombesin and to compare the in vitro MCF7 breast cancer cell uptake and biodistribution profile in mice with that of (99m)Tc-EDDA/HYNIC-Lys(3)-bombesin. The results suggest a higher lipophilicity for (99m)Tc(CO)(3)-triazole-Lys(3)-bombesin which explains its higher in vivo hepatobiliary elimination. Pancreas-to-blood ratio for (99m)Tc(CO)(3)-triazole-Lys(3)-bombesin was 4.46 at 3 h and both bombesin radiopharmaceuticals showed specific recognition for GRP receptors in MCF7 cancer cells. Click chemistry is a reliable approach for [(99m)Tc(CO)(3)] labeling of Lys(3)-bombesin.

Solution-phase parallel synthesis of substituted chalcones and their antiparasitary activity against Giardia lamblia.

A library of 25-membered chalcones was prepared by parallel synthesis. Substituted acetophenones and benzaldehydes were condensed using the Claisen-Schmidt base-catalyzed aldol condensation. Several chalcones showed in vitro antiparasitic activity against Giardia lamblia. The highest activity observed for the IC(50) values were 12.72, 15.05 and 15.31 microg/mL, respectively; these are potential leads for the development of antigiardial compounds.

Solid phase synthesis of N-alkyl-bis-o-aminobenzamides for metal ion sensing based on a fluorescent dansyl platform.

In this paper, we report the synthesis on Merrifield's resin of alkyl-bis-o-aminobenzamides labeled with a fluorescent dansyl group for use in metal ion recognition. The influence of alkyl groups with different long chains (n = 1, 2, 4, 6) on the spectral fluorescence characteristics was studied. The sensing properties of the beads were evaluated by packing the resins into a flow-through cell for use in a FIA (flow injection analysis)format. Results demonstrated that for those materials with a longer alkyl chain, the fluorescence emission increased upon Li+, Na+, K+, Ca2+, and Mg2+ addition with a higher sensitivity for Mg2+. On the contrary,a fluorescence quenching was observed when Cu2+, Fe3+, or Zn2+ ions were added. The potential applicability of the sensing approach described in this paper for magnesium ions and the sensing response mechanism are outlined.

Library preparation of derivatives of 1,4,10,13-tetraoxa-7,16-diaza-cycloctadecane and their fluorescence behavior for signaling purposes.

In the present work, we report the library preparation on solid supports of 20 derivatives of 1,4,10,13-tetraoxa-7,15-diaza-cycloctadecane 1(a-e)(w,x,y,z) carrying a fluorescent dansyl group. The sensing fluorescence behavior of these materials toward alkali and alkali earth metal ions was studied by packing the beads into a conventional flow-through cell in a FIA (flow injection analysis) approach. The fluorescence emission of these materials' responses shows a fluorescence increase to Li+, Na+, K+, NH4+, Ca2+, and Mg2+ with maximum sensitivity for Mg2+ over the rest of the ions. The analytical potential of these materials is outlined, and the sensing response mechanism, based on a photoinduced electron-transfer process, is proposed.

Fluorometric monitoring of organic reactions on solid phase.

The direct monitoring of reaction progress on solid supports by fluorescence spectroscopy is described. An immobilized fluorescent tracer molecule (dansyl chloride) is used to monitor the reaction on OH resins (Argopore Wang, PS Wang, and Argogel Wang), both in batch and in parallel chemistry. Fluorescence measurements were obtained directly on solid phase. The method demonstrated to be a valuable tool for the quantitative determination of resin-bound hydroxyl groups, to study reaction kinetics and for continuously monitoring the progress of the conversion of the hydroxyl resins into the chlorinated ones. The procedure proposed is highly sensitive compared to the traditional ones. The system can be extended to monitor a variety of reactions on solid supports, and in conjunction with a well-established technique such as flow analysis, basic studies on solid-phase become possible.

The use of solid-phase supported 1-N-piperazine-4-N-carboxaldehyde in Vilsmeier reactions.

A Vilsmeier salt supported on solid phase was prepared using piperazine bound to Merrifield resin. Piperazine was selected because it contains two secondary amines: one of the amines is protected upon binding to the resin, and the second was formylated to give resin-1-N-piperazine-4-N-carboxaldehyde (9). Activation of the formamide with either bis(trichloromethyl)carbonate (BTC) or POCl(3) afforded the Vilsmeier salt 10. Several olefins were used to test the supported Vilsmeier reagent. The in-solution activation with BTC and POCl(3) of various secondary amides was also evaluated: dimethylformamide (1), N-methyformanilide (4), 4-formylmorpholine (5), and 1,4-dicarboxylpiperazine (6), which showed that amides with one additional heteroatom increase the yields in the Vilsmeier salt formation.

Syntheses of quinazoline-2,4-dione alkaloids and analogues from Mexican Zanthoxylum species.

Quinazolinone and quinazolinedione derivatives are of considerable interest due to their wide array of pharmacological properties. In this paper we report the synthesis of ten quinazolinediones. The previous isolation of two of these compounds, namely 1-methyl-3-(2'-phenylethyl)-1H,3H-quinazoline-2,4-dione and 1-methyl-3-[2'-(4'- methoxyphenyl)ethyl]-lH,3H-quinazoline-2,4-dione, from the seed husks of Mexican Zanthoxylum species has been reported.

Method for analysis of polymer-supported organic compounds using mass spectrometry direct insertion.

A new approach on the use of mass spectrometry direct-insertion and a quadrupole detector for analysis of organic compounds supported in solid phase has been developed. This is a simple and efficient method based on cleavage due to the thermal-instability of the benzylic group of most commercial resins. The cleavage of supported compounds takes place in the spectrometer as a consequence of the high temperature in the instrument's chamber. These compounds are detected using a similar fragmentation pattern and a molecular ion corresponding to the same compound obtained by traditional synthesis. Polymer degradation fragments do not interfere with the spectrum interpretation, because only a few peaks and low intensities are detected. We report here the identification of different types of compounds supported in Merrifield resin, such as bis-o-aminobenzamides and simple aromatic and aliphatic compounds, using this new approach.