Catalytic hydrogenolysis-reduction of aryl phosphate esters

Hydrogenation of cyclic unsaturated oxyphosphoranes. A novel method for reduction of .alpha. diketones to ketones

“…The aminophthalides would be expected to be oxidized to 3-aminophthalate (3), which has been demonstrated to be the oxidation product and the emitting species in luminol chemiluminescence. 6 The expected oxidation mechanism for the aminophthalides would be that of radical autoxidation, consistent with the mechanism established for hydrocarbon oxidations3•4 (Scheme II). Thus, we expected to generate an independent Scheme II.…”

Synthesis and Immunobiological Activity of an Original Series of Acyclic Lipid A Mimics Based on a Pseudodipeptide Backbone

“…The desired pseudodipeptide 21 could be obtained in 56% yield using IIDQ (2-isobutyloxy-1-isobutyloxycarbonyl-1,2-dihydroquinoline) 30 as the coupling agent (Scheme ). Compound 21 was then phosphorylated by way of the phosphoramidite technique, to give derivative 22 , which was then deprotected by two successive hydrogenolyses, the first one in the presence of Pd on charcoal to cleave the benzyl groups, and the second one in the presence of platinum oxide to cleave the phenyl phosphates …”

Hydrogenolysis of unsaturated phosphate esters

“…The reactors and experimental conditions for hydrogenation were as previously described. 3 For the analytical experiments the reaction flask was charged with 25 ml of absolute ethanol ca. 0.020 M in the compound to be investigated and ca.…”

“…It had previously been reported that diethyl isopropenyl phosphate (I) absorbed 2 mol of hydrogen over Adams catalyst yielding as the observed product diethylphosphoric acid; when palladium was used as the catalyst, only 1 mol of hydrogen was absorbed and diethyl isopropyl phosphate was observed to be the product. 1 In the course of our investigations on the hydrogenolysis of aryl phosphate esters2, 3 it was observed that diethyl 1-cyclohexenyl phosphate (II) underwent hydrogenolysis over Adams catalyst with the formation of cyclohexane. With this observation it became of interest to investigate in detail the hydrogenolysis of saturated and unsaturated aliphatic phosphate esters.…”

“…If a generality of reaction could be established here it would further extend the already well-known scheme of nonhydrolytic phosphate ester cleavages involving aryl and benzylic linkages. [2][3][4][5][6] To test the generality of this reaction and to elucidate the sequence of reaction steps the series of vinylic phosphate esters I-V was prepared and subjected to standard hydrogenolysis conditions. In all cases direct observation of hydrocarbon product and any intermediates was attempted.…”