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A highly efficient method for the synthesis of [α.sup.1]-oxindole-α-hydroxyphosphonates via nano-rod ZnO catalyzed hydrophosphonation of isatin derivatives was developed. The reaction products are in excellent yields using the catalytic system nano-rod ZnO (25 mol%) under solvent-free conditions at room temperature. The catalyst can be reused several times without any significant loss of its activity. Key words: nano-rod ZnO, hydrophosphonation, C-P bond formation, solvent-free. On a mis au point une methode tres efficace de synthese des [[alfa].sup.1]-oxindole-[alfa]-hydroxyphosphonates par hydrophosphonation de derives de l'isatine catalysee par des nanotiges de ZnO. Les produits de reaction sont obtenus avec un excellent rendement en utilisant le systeme catalytique de nanotiges de ZnO (25 mol%) sans solvant a la temperature ambiante. Le catalyseur peut etre reutilise plusieurs fois sans perte appreciable de son activite. [Traduit par la Redaction] Mots-cles: nanotiges de ZnO, hydrophosphonation, formation d'une liaison C-P, sans solvant., Introduction Considering the increasing environmental pollution and its drastic impact on living systems, green chemistry demands eco-friendly organic chemical processes. (1) Hence, the significance of greener pathways in organic synthesis [...]

Phosphonate natural products possess a range of biological activities as a consequence of their ability to mimic phosphate esters or tetrahedral intermediates formed in enzymatic reactions involved in carboxyl group metabolism. The dianionic form of these compounds at pH 7 poses a drawback with respect to their ability to mimic carboxylates and tetrahedral intermediates. Microorganisms producing phosphonates have evolved two solutions to overcome this hurdle: biosynthesis of monoanionic phosphinates containing two P-C bonds or esterification of the phosphonate group. The latter solution was first discovered for the antibiotic dehydrophos that contains a methyl ester of a phosphonodehydroalanine group. We report here the expression, purification, substrate scope, and structure of the O-methyltransferase from the dehydrophos biosynthetic gene cluster. The enzyme utilizes S-adenosylmethionine to methylate a variety of phosphonates including 1-hydroxyethylphosphonate, 1,2-dihydroxyethylphosphonate, and acetyl-1aminoethylphosphonate. Kinetic analysis showed that the best substrates are tripeptides containing as C-terminal residue a phosphonate analog of alanine suggesting the enzyme acts late in the biosynthesis of dehydrophos. These conclusions are corroborated by the X-ray structure that reveals an active site that can accommodate a tripeptide substrate. Furthermore, the structural studies demonstrate a conformational change brought about by substrate or product binding. Interestingly, the enzyme has low substrate specificity and was used to methylate the clinical antibiotic fosfomycin and the antimalaria clinical candidate fosmidomycin, showing its promise for applications in bioengineering. antibiotics | bioengineering | conformational change | X-ray crystallography | domain-swap doi/ 10.1073/pnas.1006848107

This article demonstrates how to prepare microfabricated columns (microcolumns) for organophosphonate and organosulfur compound separation that rival the performance of commercial capillary columns. Approximately 16 500 theoretical plates were generated with a 3 m long OV-5-coated microcolumn with a 0.25 [micro]m phase thickness using helium as the carrier gas at 20 cm/s. Key to the advance was the development of deactivation procedures appropriate for silicon microcolumns with Pyrex tops. Active sites in a silicon-Pyrex microcolumn cause peak tailing and unwanted adsorption. Experimentally, we found that organosilicon hydride deactivation lowers adsorption activity in microcolumns more than silazane and silane treatments. But without further treatment, the phosphonate peaks continue to tail after the coating process. We found that heat treatment with pinacolyl methylphosphonic acid (PMP) eliminated the phosphonate peak tailing. In contrast, conventional resilylation employing N,O-bis(trimethylsilyl)acetamide, hexamethyldisilazane, and 1-(trimethylsilyl)imidazole does not eliminate peak tailing. Column activity tests show that the PMP treatment also improves the peaks for 2,6-dimethyl aniline, 1-octanol, and 1-decanol implying a decrease in the column's hydrogen bonding sites with the PMP treatment. FT-IR analysis shows that exposure to PMP forms a bond to the stationary phase that deactivates the active sites responsible for organophosphonate peak tailing.

The need for the detection of chemical warfare agents (CWAs) is no longer confined to battlefield environments because of at least one confirmed terrorist attack, the Tokyo Subway [Emerg. Infect. Dis. 5, 513 (1999)] in 1995, and a suspected, i.e., a false-alarm of a CWA in the Russell Senate Office Building [Washington Post, 9 February 2006, p. B01]. Therefore, detection of CWAs with high sensitivity and low false-alarm rates is considered an important priority for ensuring public safety. We report a minimum detection level for a CWA simulant, dimethyl methyl phosphonate (DMMP), of < 0.5 ppb (parts in [10.sup.9]) by use of a widely tunable external grating cavity quantum cascade laser and photoacoustic spectroscopy. With interferents present in Santa Monica, California street air, we demonstrate a false-alarm rate of 1 : [10.sup.6] at a detection threshold of 1.6ppb. OCIS codes: 140.5965, 300.6390.

A mild method is developed for preparing o-acylbenzylphosphonates by the reactions of arynes with [beta]-ketophosphonates. The carbon-carbon [sigma]-bonds of 2-oxoprpylphosphonates are selectively cleaved and added to arynes providing the corresponding 2-acylbenzylphosphonates in the presence of CsF and THF.

The reaction of salicyaldehydes with allenylphosphonates in the presence of a base has led to phosphono-chromenes and allylic phosphonates and the interconversion of E and Z isomers of phosphono-chromenes is shown by [super 31]P NMR spectroscopy. Allylic phosphonyl ether is used in the Horner-Wadsworth-Emmons reaction to produce substituted trans-1,3-butadiene.