Sulfonate protecting groups. Regioselective sulfonylation of myo-inositol orthoesters-improved synthesis of precursors of D- and L-myo-inositol 1,3,4,5-tetrakisphosphate,myo-inositol 1,3,4,5,6-pentakisphosphate and related derivatives

The regioselectivity of sulfonylation of myo-inositol orthoesters was controlled by the use of different bases to obtain the desired sulfonate. Monosulfonylation of myo-inositol orthoesters in the presence of one equivalent of sodium hydride or triethylamine resulted in the sulfonylation of the 4-hydroxyl group. The use of pyridine as a base for the same reaction resulted in sulfonylation of the 2-hydroxyl group. Disulfonylation of these orthoesters in the presence of excess sodium hydride yielded the 4,6-di-O-sulfonylated orthoesters. However, the use of triethylamine or pyridine instead of sodium hydride yielded the 2,4-di-O-sulfonylated orthoester. Sulfonylated derivatives of myo-inositol orthoesters were stable to conditions of O-alkylation but were cleaved using magnesium/methanol or sodium methoxide in methanol to regenerate the corresponding myo-inositol orthoester derivative. These new methods of protection-deprotection have been used: (i) for the efficient synthesis of enantiomers of 2,4-di-O-benzyl-myo-inositol, which are precursors for the synthesis of D- and L-myo-inositol 1,3,4,5-tetrakisphosphate; (ii) for the preparation of 2-O-benzyl-myo-inositol which is a precursor for the preparation of myo-inositol 1,3,4,5,6-pentakisphosphate.     

Sulfonate protecting groups. Improved synthesis of scyllo-inositol and its orthoformate from myo-inositol

A convenient high yielding method for the preparation of scyllo-inositol and its orthoformate from myo-inositol, without involving chromatography is described. myo-Inositol 1,3,5-orthoformate was benzoylated to obtain 2-O-benzoyl-myo-inositol 1,3,5-orthoformate. This diol was tosylated and the benzoyl group removed by aminolysis in a one-pot procedure to obtain 4,6-di-O-tosyl-myo-inositol 1,3,5-orthoformate. Swern oxidation of the ditosylate, followed by sodium borohydride reduction and methanolysis of tosylates gave scyllo-inositol 1,3,5-orthoformate (isolated as the triacetate). Aminolysis of the acetates followed by acid hydrolysis of the orthoformate moiety with trifluoroacetic acid gave scyllo-inositol in an overall yield of 64%.     

Linear alkanesulfonates as carbon and energy sources for gram-positive and gram-negative bacteria

Several bacteria from soil and rainwater samples were enriched and isolated with propanesulfonate or butanesulfonate as sole carbon and energy source. Most of the strains isolated utilized nonsubstituted alkanesulfonates with a chain length of C3–C6 and the substituted sulfonates taurine and isethionate as carbon and energy source. A gram-positive isolate, P40, and a gram-negative isolate, P53, were characterized in more detail. Phylogenetic analysis grouped strain P40 within group IV of the genus Rhodococcus and showed a close relationship with Rhodococcus opacus. After phylogenetic and physiological analyses, strain P53 was identified as Comamonas acidovorans. Both bacteria also utilized a wide range of sulfonates as sulfur source. Strain P40, but not strain P53, released sulfite into the medium during dissimilation of sulfonated compounds. Cell-free extracts of strain P53 exhibited high sulfite oxidase activity [2.34 U (mg protein)^–1] when assayed with ferricyanide, but not with cytochrome c. Experiments with whole-cell suspensions of both strains showed that the ability to dissimilate 1-propanesulfonate was specifically induced during growth on this substrate and was not present in cells grown on propanol, isethionate or taurine. Whole-cell suspensions of both strains accumulated acetone when oxidizing the non-growth substrate 2-propanesulfonate. Strain P40 cells also accumulated sulfite under these conditions. Stoichiometric measurements with 2-propanesulfonate as substrate in oxygen electrode experiments indicate that the nonsubstituted alkanesulfonates were degraded by a monooxygenase. When strain P53 grew with nonsubstituted alkanesulfonates as carbon and energy source, cells expressed high amounts of yellow pigments, supporting the proposition that an oxygenase containing iron sulfur centres or flavins was involved in their degradation. Received: 21 December 1998 / Accepted: 18 March 1999     

Hydrogen bond network structures based on sulfonated phosphine ligands: The effects of complex geometry, cation substituents and phosphine oxidation on guanidinium sulfonate sheet formation

Interactions between guanidinium cations and the sulfonate groups on the phosphine [PPh₂C₆H₄-m-SO₃]⁻ have been exploited to incorporate iridium(I) centres into hydrogen-bonded networks. The crystal structure of [C(NH₂)₃]₂{trans-[IrCl(CO)(PPh₂C₆H₄-m-SO₃)₂]} (4) contains hexagonal guanidinium sulfonate (GS) sheets in which both of the sulfonate groups from each complex anion form hydrogen bonds within the same sheet. The crystal structures of [C(NH₂)₂(NHMe)][PPh₂C₆H₄-m-SO₃] (5) and [C(NH₂)₂(NHEt)][PPh₂C₆H₄-m-SO₃] (6) reveal that the GS sheets can tolerate the loss of one hydrogen bond donor, though twisting occurs to accommodate the alkyl group. However, the crystal structure of [C(NH₂)₂(NMe₂)][PPh₂C₆H₄-m-SO₃] (7) shows that ribbon structures are formed instead of sheets when two hydrogen bond donors are lost. The compound [C(NH₂)₂(NHMe)]₂{trans-[IrCl(CO)(PPh₂C₆H₄-m-SO₃)₂]} · 3/8H₂O (8) contains hydrogen-bonded cylinders as opposed to sheets. This is a likely consequence of a mismatch between the intramolecular S?S distance present in the anion, and the closer S?S distance present in a twisted GS sheet such as that in 5. The crystal structures of [C(NH₂)₂(NHEt)][P(O)Ph₂C₆H₄-m-SO₃] (9) and [C(NH₂)₂(NMe₂)][P(O)Ph₂C₆H₄-m-SO₃] · H₂O (10) show that the phosphine oxide group successfully competes with the sulfonate as a hydrogen bond acceptor. The crystal structure of 9 contains hydrogen-bonded ribbons that are interlinked through the anions which act as pillars to form a layer structure. In contrast, the crystal structure of 10 contains hydrogen-bonded sheets that involve cations, sulfonate groups, phosphine oxides and the included water molecule. These sheets are linked into a three-dimensional network through the anion pillars.     

Taurine serves as sole source of nitrogen for aerobic and anaerobic growth by <Emphasis Type="Italic">Klebsiella</Emphasis> sp.

The sulfur of taurine can be assimilated by Klebsiella sp. during aerobic growth, but not fermentative growth. However, taurine’s N can be utilized by this bacterium as sole nitrogen source for both aerobic and anaerobic growth. Two other amino-containing sulfonates (3-aminopropanesulfonate and cysteate) were also examined for their abilities to serve as nitrogen sources for Klebsiella sp. during the different growth conditions. The result shows that 3-aminopropanesulfonate only supports aerobic growth while cysteate does not under either condition.