From Simple Diols to Carbohydrate Derivatives of Phenylarsonic Acid

Abstract

A series of spiro-arsoranes bearing a phenyl moiety as the fifth substituent were synthesized applying open-chain, as well as cyclic vicinal diols, as chelating molecules by condensation reactions in aprotic solvents. The products synthesized are the spiro compounds of the general formula PhAs(DiolH(-2))(2) derived from the vicinal diols meso-2,3-butanediol, PhAs(meso-2,3-ButdH(-2))(2) (1), exo-cis-2,3-norbornanediol, PhAs{exo-cis-NobdH(-2)}(2) (2), cis-1,2-cyclopentanediol, PhAs(cis-1,2-CptdH(-2))(2) (3), anhydroerythritol, PhAs(AnErytH(-2))(2) (4), cis-1,2-cyclohexanediol, PhAs(cis-1,2-ChxdH(-2))(2) (5), and rac-trans-1,2-cyclohexanediol, rac-{PhAs(trans-1,2-ChxdH(-2))(2)} (6) which were identified as mononuclear compounds. A novel dimeric double-spiro environment for oxyarsoranes was found in the reaction products derived from the sterically demanding diols 1,1'-bicyclohexyl-1,1'-diol {PhAs(BhxdH(-2))O}(2) (7) and perfluorpinacol, {PhAs(FpinH(-2))O}(2) (8). The stability of the compounds in acidic and neutral aqueous media in the presence of organic co-solvents was investigated. A convenient synthetic procedure for spiro-oxyarsoranes, applying water as the solvent, was developed and proven to be advantageous. All of the compounds synthesized in this study were characterized by means of melting-point measurement, single-crystal X-ray analysis, NMR, IR, Raman, UV/vis, and mass spectrometry. The principles found for these reactions were valid for the methyl glycosides of beta-D-ribofuranose and alpha-D-mannopyranose. The spiro-arsorane derived from methyl alpha-D-mannopyranoside, PhAs(Me-alpha-D-Manp2,3H(-2))(2) (9), is the first example of a structurally characterized carbohydrate-arsenic(V) compound.

Enticing Cobalt into Planarity: Can a Pair of Diolato Ligands Make It Happen?

“…It was therefore remarkable that, with the perfluoropinacolato chelator ((FpinH −2 ) 2− , Fpin=perfluoropinacol; for the sake of consistency with a previous work by our group,2 we use this abbreviation; in Ref. 1b, the abbreviation ddfp is used instead of (FpinH −2 ) 2− ), not only a second example of a planar high‐spin bisdiolato iron(II) but also a high‐spin d 7 cobalt(II) analogue was recently reported 1b.…”

Reversible Layer‐by‐Layer Deposition on Solid Substrates Inspired by Mussel Byssus Cuticle

“…In this work, we continue to use the DTBS triflate reagent for a more general examination of the silicon‐binding sites of the carbohydrates and derivatives thereof. The investigation is aimed as a contribution to the question of whether tetracoordinate silicon, rather than penta‐ or hexacoordinate central silicon atoms, should be considered a candidate for silicon‐carbohydrate chelates, which may occur in the course of silica biomineralization 4. As reported previously, DTBS derivatives of reducing sugars had shown a variety of bonding patterns including five‐, six‐ and seven‐membered sila cycles and aldoses in less stable configurations and conformations 5.…”

The crystal structure of bi-1,1′-cyclopentane-1,1′-diol, C10H18O2

“…One major factor influencing on the chelation ability of a ligand with vicinal donor sites is the interplay of the spatial pretense on the immediate backbone of the ligand next to the donor sites as well as the size and preferred coordination number and polyhedron of the central atom. A remarkable example in this context is the situation encountered for spirocyclic phenylarsoranes where the change from pinacol as chelator [9] to perfluoropinacol resulted in a completely changed coordination pattern in the resultant product [10]. In order to understand the rules behind thesesometimes drasticchanges it is advisable to explore the metrical parameters apparent for ligands to be applied in such studies.…”