Chemical Synthesis and Quantitative Estimation of 3‐Deoxy d‐manno‐Octulosonic Acid

Abstract

3-Deoxy D-manno-octulosonic acid has been synthesised starting from D-mannose via 2-deoxy D-manno heptose, cyanohydrine addition, and selective oxidation of the epimeric hydroxyl group of the resulting 3-deoxy octonic acids. When treated with periodate in 0.1 N sulphuric acid solution a t O", the deoxy octulosonic acid and other 3-deoxy aldulosonic acids all yield one molar equivalent of P-formyl pyruvate. Conditions are described in which /I-formyl pyruvate can be estimated by the thiobarbituric acid method ; hence, when treated successively with periodate and thiobarbiturate, all 3-deoxy aldulosonic acids have the same molar extinction coefficient and eight carbon atoms are known to be important intermediates of carbohydrate metabolism in various organisms, a general method was sought by which these compounds, as well as their phosphate esters, could be made readily accessible. In 1944 it was reported that o-gluconic acid and D-galactonic acid could be oxidised to aldulosonic acids by chlorate in the presence of a vanadium pentoxide catalyst [lo]. It was therefore expected that similar treatment of 3-deoxy aldonic acids would afford the corresponding aldulosonic acids. This was found to be the case : the present paper reports an unambiguous chemical synthesis of 3-deoxy D-manno-octulosonic acid starting from D-mannose. Conditions are described in which 3-deoxy D-manno-octulosonic acid and other 3-deoxy aldulosonic acids, when treated with periodate, yield one molar equivalent of ,9-formyl pyruvate; these acids can thus be estimated quantitatively in the thiobarbituric acid assay without standards. EXPERIMENTAL PROCEDURESXynthesis of 3-Deoxy D-manno-Octulosonic Acid ( V ) 1,2-Di-deoxy-l-nitro-3,4,5,6,7-penta-O-acetyl D-manno-heptene [ll, 121 (10 g) in 600 ml absolute ethanol was hydrogenated over 1 g palladium black, until 1.05 moles of hydrogen (570 ml a t 25" and 760 mm) had been consumed. The filtered solution was then concentrated in vacuo to a crystallising syrup, which was redissolved in 75 ml ethanol. Sodium hydroxide (100 ml, 2 N) was added in small portions to this solution kept below f5". The resulting deep red solution was then added rapidly, but dropwise, to a stirred solution of 25 ml concentrated sulphuric acid in 35 ml water maintained in an ice-bath. When the addition was complete, the reaction mixture was diluted with 1.5 1 water and neutralised with solid calcium carbonate. All solids were removed by filtration, the combined filtrate and washings passed through columns of ion exchange resins (Amberlite IR 120 H+ and I R 45 OH-, 250 ml each) and the effluent was concentrated in vacuo to a small volume.Sodium hydrogen carbonate (3.13 g) was added to the above solution of crude 2-deoxy D-mannoheptose and the volume adjusted to 186ml with water. This mixture was then added to 1.5 g sodium hydroxide and 3.0 g potassium cyanide in 186 ml water frozen to the walls of a 1 1 round bottomed flask. The flask was agitated until the mixture became homogeneous and then set aside a t room temperature overnig...

Synthesis of 3‐Deoxy‐D‐manno‐2‐octulosonic Acid (KDO)

“…However, l a reacts rapidly with the 14-electron species (iPr3P)2RhC1 (pentane, 2 5 T , 10 min; yield 56%) to give the binuclear complex 4aI3], in which the "metallaallene" is bound to the square-planar coordinated rhodium atom, similarly to an alkenel'] or an alkyne12"~b1. [Rh]=CSHs(R$P)Rh, R'=rl'i (P atom of the C,H,(R;P)Rh group designated as P' in the "P-NMR spectrum of 4a [3]); a : R = H ; b: R=Ph.…”

Ambidentate Behavior of Mononuclear Vinylidenerhodium Complexes—Novel CC Coupling of a Methyl to a Vinylidene Group

“…However, l a reacts rapidly with the 14-electron species (iPr3P)2RhC1 (pentane, 2 5 T , 10 min; yield 56%) to give the binuclear complex 4aI3], in which the "metallaallene" is bound to the square-planar coordinated rhodium atom, similarly to an alkenel'] or an alkyne12"~b1. [Rh]=CSHs(R$P)Rh, R'=rl'i (P atom of the C,H,(R;P)Rh group designated as P' in the "P-NMR spectrum of 4a [3]); a : R = H ; b: R=Ph. Solid 4a is stable under inert gases.…”

Chemotypes ofVibrio parahaemolyticuslipopolysaccharides

“…KDO was determined by the thiobarbituric acid method of Charon et al [11] after samples were hydrolysed in 0.05 M acetate buffer, pH 4.1 (1 mg lipopolysaccharide in 1 ml buffer) at 100°C for 20 rain [121.…”