D-Ribonic acid

The extension of the salt-acid,27 phenylhydrazide,28 and amide rules29 to the derivatives of the 2-(hydroxymethyl) sugars by Schmidt and Weber-Molster30 indicated that the configuration of C2 in hamamelonic acid is the same as that of D-ribonic acid. Finally, the d-ribo configuration of the sugar was established by the synthesis of hamamelonic acid and its C2 epimer from D-ery/ftro-pentulose31 by the cyanohydrin reaction of Fischer and Kiliani. 

The pyrimidine nucleosides from ribonucleic acid (uridine and cytidine) present a more formidable problem, since they cannot be hydrolyzed by dilute mineral acid, and the use of concentrated acid usually destroys the sugar moiety. It was observed, however, that simultaneous bromination, hydrolysis, and oxidation of cytidine (with bromine-hydrobromic acid) yields 5-bromouracil plus D-ribonic acid.60 Since cytidine can be deaminated to uridine with nitrous acid,61 both of these pyrimidine nucleosides must... 

The cyclohexenone 16 would arise from the enol silyl ether containing the dimethyl acetal 15, which originates from one-step opening of the phenylsulfonylmethyl furanose 14. Thus, the starting material simplifies to commercially available D-ribonic acid y-lactone. 

The oxidation of D-ribose to D-ribonic acid was first carried out by Levene and Jacobs78 who used bromine in an aqueous suspension of barium carbonate as an oxidant more recent work bearing upon the oxidation of ribose to ribonic acid with alkaline hypoiodite63 and with bromine-barium benzoate has already been mentioned. More vigorous oxidation gives n o-trihydroxyglutaric acid.3... 

The 3- and 5-phosphates of D-ribose have both been obtained through the hydrolysis of naturally occurring ribosides. In 1908 Levene and Jacobs122 subjected the barium salt of inosinic acid to acid hydrolysis and obtained a pentose phosphate as its barium salt. Shortly thereafter the same authors78 showed that, under the conditions which normally convert a pentose to a pentaric acid, this phosphate was oxidized only to a phosphorylated D-ribonic acid and it was evident, therefore, that... 

C5H7N04 acrylamide glycolic acid, anhydrous 6737-24-2 25.00 1.2996 2 4960 C5H805 D(- -)-ribonic acid g-lactone 5336-08-3 25.00 1.2601 2... 

The C33-C37-unit of (-F)-calyculin A (a marine natural product) is an amide derived from 5-0-methyl-4-deoxy-4-dimethylamino-D-ribonic acid, which has been prepared by Evans and... 

SCHEME 13.44 Synthesis of a 4-deoxy-4-dimethylamino-D-ribonic acid derivative. 

The C33-C37-unit of (-F)-calyculin A (a marine natural product) is an amide derived from 5-0-methyl-4-deoxy-4-dimethylamino-D-ribonic acid that has been prepared by Evans and co-workers [250]. A-Protection of sarcosine as benzyl carbamate affords acid 118 which is activated and used to iV-acylate the (5)-phenylalanine-derived oxazolidinone. This gives 119 that is methoxymethylated diastereoselectively (98 2) to give 120. Reductive removal of the chiral auxiliary, followed by Swem oxidation forms aldehyde 121 with little racemization if... 

D-Ribonic acid, esters D-psicosides from, 272 Ribonucleic acid. See RNA Ring cleavage electrocyclic (cycloreversion) [l+l-i- 2]- double CO elimination, 78, 339 [1 + 4]- CO elimination, 337 S02 elimination, 80,153 [2 + 2]- benzene elimination, 331, 332-333 prismane opening, 330-331 rhodium( 1 + )-catalysed, 332 thermal, 79-80... 

D-Ribonic acid, 2-C-[(phosphonooxy)methyI]-, 5-(dihydrogen phosphate) 4249 ... 

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