6.1. Oxadiazoles 4154 6.2. Diazaphospholes 4154 7. Six-Membered Heterocycles with One Heteroatom 4155 7.1. Pyridines 4155 7.2. Pyridinones 4155 7.3. Quinolines 4156 7.4. Quinolinones 4157 7.5. Isoquinolines 4157 7.6. Acridines 4158 7.7. Pyranones 4158 7.8. Flavones 4159 8. Six-Membered Heterocycles with Two Heteroatoms 4159 8.1. Pyridazinones 4159 8.2. Pyrimidines 4159 8.3. Pyrimidinones 4160 8.4. Quinazolines 4162 8.5. Quinazolinones 4162 8.6. Quinoxalines 4164 8.7. Quinoxalinediones 4165 8.8. Oxazines 4165 8.9. Oxazinones 4166 8.10. Thiazines 4166 9. Six-Membered Heterocycles with Three Heteroatoms 4166

Solvent-free heterocyclic synthesis.

Organotin(IV)n+ complexes formed with biologically active ligands: equilibrium and structural studies, and some biological aspects

Background: We recently developed a photonic crystal glucose-sensing material (Alexeev et al., Anal Chem 2003;75:2316–23), which consists of a crystalline colloidal array embedded within a polymer network of a polyacrylamide-poly(ethylene glycol) hydrogel with pendent phenylboronic acid groups. The aim of the present work was to improve this approach for application to noninvasive or minimally invasive monitoring of glucose.

Methods: We used new boronic acid derivatives such as 4-amino-3-fluorophenylboronic acid and 4-carboxy-3-fluorophenylboronic acid as the molecular recognition elements to achieve sensing at physiologic pH values.

Results: The improved photonic glucose-sensing material sensed glucose in the range of the 100 μmol/L concentrations found in tear fluid. The detection limits were ∼1 μmol/L in synthetic tear fluid. The visually evident diffraction color shifted across the entire visible spectral region from red to blue over the physiologically relevant tear-fluid glucose concentrations. This sensing material is selective for glucose over galactose, mannose, and fructose.

Conclusions: These new glucose sensors have properties appropriate for use in such glucose-sensing applications as ocular inserts or diagnostic contact lenses for patients with diabetes mellitus.

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Photonic crystal glucose-sensing material for noninvasive monitoring of glucose in tear fluid.

Fluorinated Ylides and Related Compounds.

Phytochemistry of Acacia—sensu lato

Anellated heterophospholes and phospholides and analogies with related non-phosphorus systems.

Synthesis and characterization of diorganotin(IV) complexes of tetradentate Schiff bases: crystal structure of n-Bu2Sn(Vanophen)

Synthesis of 1H-1,3-benzazaphospholes: substituent influence and mechanistical aspects

1H-1,3-Benzazaphospholes: The Organometallic Route and a New Three-Step Synthesis with Reductive Ring Closure

1H-1, 3-Benzazaphospholes react with M(CO)5(THF) (M = Cr, Mo, W) to give thermally and relatively air stable η1-(1H-1, 3-Benzazaphosphole-P)M(CO)5 complexes. The 1H- and 13C-NMR-data are in accordance with the preservation of the phosphaaromatic π-system of the ligand. The strong upfield 31P coordination shift, particularly of the Mo and W complexes, forms a contrast to the downfield-shifts of phosphine-M(CO)5 complexes and classifies benzazaphospholes as weak donor but efficient acceptor ligands. Nickelocene reacts as organometallic species with metalation of the NH-function. The resulting ambident 1, 3-benzazaphospholide anions prefer a μ2-coordination of the η5-CpNi-fragment at phosphorus to coordination at nitrogen or a η3-heteroallyl-η5-CpNi-semisandwich structure. This is shown by characteristic NMR data and the crystal structure analysis of a η5-CpNi-benzazaphospholide. The latter is a P-bridging dimer with a planar Ni2P2 ring and trans-configuration of the two planar heterocyclic phosphido ligands arranged perpendicular to the four-membered ring.



Metallierte 1, 3-Azaphosphole: η1-(1H-1, 3-Benzazaphosphol-P)M(CO)5 und μ2-[(1, 3-Benzazaphospholid-P)(cyclopentadienid)nickel] Komplexe



1H-1, 3-Benzazaphosphole reagieren mit M(CO)5(THF) (M = Cr, Mo, W) zu thermisch und zumindest kurzzeitig luftstabilen η1-(1H-1, 3-Benzazaphosphol-P)M(CO)5-Komplexen. Die 1H- und 13C-NMR-Daten sind mit dem Erhalt des phosphaaromatischen π-Systems im Liganden im Einklang. Die starke 31P-Koordinationsverschiebung zu hohem Feld, vor allem der Mo- und W-Komplexe, steht im Gegensatz zur Koordinationsverschiebung zu tiefem Feld, beobachtet bei Phosphin-M(CO)5 Komplexen, und verweist auf schwache Donator-, aber gute Akzeptoreigenschaften der Liganden. Nickelocen reagiert als Ubergangsmetallorganyl unter Metallierung der NH-Funktion. Die resultierenden ambidenten 1, 3-Benzazaphospholid-Anionen bevorzugen eine μ2-Koordination des η5-CpNi-Fragments am Phosphor gegenuber N-Koordination oder einer η3-Heteroallyl-η5-CpNi-Semisandwich-Struktur. Dies wird durch charakteristische NMR-Daten und die Ergebnisse der Strukturuntersuchung an Einkristallen eines η5-CpNi-benzazaphospholids belegt. Letzteres kristallisiert mit Benzol und bildet ein P-Bruckendimer mit planarem Ni2P2 Ring und trans-Konfiguration der beiden senkrecht zum Vierring angeordneten planaren heterocyclischen Phosphidoliganden.

Raj K. Bansal

Papers

Anellated heterophospholes and phospholides and analogies with related non-phosphorus systems.

Synthesis and characterization of diorganotin(IV) complexes of tetradentate Schiff bases: crystal structure of n-Bu2Sn(Vanophen)

Synthesis of 1H-1,3-benzazaphospholes: substituent influence and mechanistical aspects

1H-1,3-Benzazaphospholes: The Organometallic Route and a New Three-Step Synthesis with Reductive Ring Closure

Metalated 1, 3‐Azaphospholes: η1‐(1H‐1, 3‐Benzazaphosphole‐P)M(CO)5 and μ2‐[(1, 3‐Benzazaphospholide‐P)(cyclopentadienide)nickel] Complexes