D-Allonic acid

Allomucic acid, I, 37, 39 III, 49, 50, 58 D-Allonic acid, I, 38, 39 o-Allono-7-lactone, I, 38 Allonucleic acid, I, 196 a-D-AlIopyranoside, methyl 2,3-anhydro-... 

Until very recently, o-ribose has been such a rare and expensive sugar that the addition of hydrocyanic acid to it and the conversion of the mixed nitriles to hexonic acids have been described only a few times. From the combined experiences of Levene and Jacobs, of Phelps and Bates, and of Steiger and Reichstein, it appears that n-altronic and D-allonic acids are produced in about equal amounts, in a total yield of 70-80% of the theoretical. To separate the two acids, they were converted to calcium salts, and most of the calcium n-altronate was recovered as the characteristic hydrate containing three and one-half molecules of water of crystallization. The mother liquor was freed from calcium ions by the addition of oxalic acid, and evaporated to a sirup from which the D-allono-7-lactone crystallized. Small additional amounts of the two compounds were obtained by further treatment of the mother liquors. 

Digitoxose, therefore, represents a case wherein the Hudson lactone rule fails insofar as the lactones of digitoxonic and digitoxosecarboxylic acids are concerned, a behavior paralleled by D-allonic acid lactone of which digitoxose is a derivative. At the same time, the diamide of the glutaric acid obtained on oxidation of digitoxose now obeys Hudson s amide rule in the light of the above observations and also the lactone of this acid obeys the lactone rule. 

Benzimidazol-2-yl C-nucleosides (e.g., 107) were also synthesized by condensation of anhydroaldonic acids such as 2,5-anhydro-D-allonic acid (106) with 1,2-diaminobenzene [50JBC(186)387 69CCC247 80JCS(P1)2683 86SC35] (Scheme 33). 

The 2,5-anhydro-D-allonic acid imidate 210 (R = OR, Z = O) condensed with 2-aminomethylpyridine to form the corresponding amide 211. Dehy-drative cyclization of the latter gave 212 [84JCS(P1)229]. The reaction was also performed by employing the dithioate 210 (R = OR, R = H, Z =... 

Rosenthal and Lee prepared examples of these C-nucleosides (310) by cyclocondensation of the 2,5-anhydro-D-allonic acid 79 with 1-hydra-zinophthalazine in the presence of a coupling reagent (CR) (78MI12) (Scheme 94). 

Amidation of 2,5-anhydro-D-allonic acid (106) with 4,5,6-triaminopyri-midine (506) gave the corresponding amide 507, which then thermally cyclodehydrated to 7-amino-2-j8-D-ribofuranosylimidazo[4,5-d]pyrimidine (8-)8-D-ribofuranosyladenine or C-adenine) (508) (69CCC247) (Scheme 137). 

The single example of this class that is known so far (555) has been synthesized as a stable precursor for the thermolytic in situ production of the allonoylnitrile A -sulfide 556 the latter is the reactive species in the synthesis of isothiazole (Section XI Scheme 149) and 1,2,4-thiadiazole C-nucleosides (Section XIX Scheme 203). The 5-(tri-0-benzoyl-/3-D-ribofuranosyl)-l,3,4-oxathiazol-2-one (780) was obtained from the 2,5-anhydro-D-allonic acid amide 779 by heating with chlorocarbonylsulfenyl chloride (84JOC2165 91MI21) (Scheme 213). 

Katagiri et al. prepared the 2-pyriniidyl C-nucleoside 912 by two routes (85CPB102) the first involved reaction of the 2,5-anhydro-D-allonic acid derivative 65 with 3-aminocrotonamide followed by cyclization and removal of the protective groups. The second route comprised oxazine ring opening of the Spiro compound 699 with amonia. Riley obtained the same C-... 

The 3-j3-D-arabinofuranosyl pyrazole derivative (33) has been synthesized from D-mannose by the procedure outlined in Scheme 9 on deprotection with ammonia, (33) epimerized to the -D-ribofuranosyl isomer. 2,5-Anhydro-D-allonic acid derivatives have been used to synthesize the C- ym-triazoloribo-nucleosides (34) and (35) by condensation with heterocyclic hydrazine derivatives. The diazoketone (36), prepared conventionally from the acid, has been used to prepare the thiazole analogue (37) of ribavirin via the intermediate a-bromomethyl ketone (38) by condensation with an imido-thio-oxalic acid derivative,and the indazole nucleoside analogue (39) by cyclization with benzyne (Scheme 10). An acyclic diazoketone analogously prepared from D-ribonic acid similarly gave a C-ribonyl-indazole with benzyne, which could be... 

A series of 2 -deoxyribofuranosyl C-nucleosides of imidazo-fused bridgehead nitrogen systems, typified by (45), have been prepared starting from tri-O-benzoyl-2,5-anhydro-D-allonic acid. ... 

C6H9NO4 159.141 Characterised as derivs. below. Tribenzoyl 2,5-Anhydro-3,4,5-tri-0-ben-zoyl-D-allonic acid [23316-68-9]... 

The principal product of the reaction of 2,3,5-tri-O-benzoyl-D-ribofuranosyl bromide with mercury(ii) or copper(i) phenylacetylide has been shown to possess the 3-configuration by H n.m.r. examination of isopropylidenated and acylated derivatives (7, j = 0 Hz) of the debenzoylated product and by chemical degradation of the side-chain to give known 2,5-anhydro-D-allonic acid derivatives. Details have appeared on the synthesis of methyl 3-(2,3,5-tri-0-benzyl-a- and -P-D-ribofuranosyl)propiolates le.g. (74)] by reaction of 2,3,5-tri-O-benzyl-D-ribo-... 

Photochemical decarboxylation in the presence of diacetoxyiodobenzenc and the appropriate heterocycle has been used to make some compounds related to C-nucleosides, such as 167.192 The preparation of a chloromethyl ketone related to 2,5-anhydro-D-allonic acid, and of potential use in C-nucleoside synthesis, is discussed in Chapter 3. 

In the oxidation of D-aiiose to D-allonic acid, a iactone having the generai structure A is isoiated. Draw a stepwise mechanism to account for the formation of A. Use wedges and dashes to indicate the stereochemistry of aii stereogenic centers in A. 

The oxazole analogue (90) of the antitumour agent tiazofurin has been prepared from 2,S-anhydro-D-allonic acid by a fairly conventional annulation.1 1 An interesting photochemical ring expansion was used (Scheme 12) in a synthesis of the racemic hydantoin C-riboside (91), the starting material illustrated being made by a Diels-Alder-hydroxylation sequence. 1 2 Further extensions of the application of Wittig reactions for the... 

The compounds discussed in the following section closely resemble some of the compounds mentioned in the section on C-glycosides in Chapter 3. The glycosyl cyanides (278) and (279) have been converted into the amino-acids (282) and (283) by way of the sulphonates (280) and (281), respectively/ The amino-acids (282) and (283) were used to prepare novel polymers which exhibited the properties both of polysaccharides and proteins. Investigations on the synthesis of puro-mycin analogues have led to the preparation of the 2,5-anhydro-D-allonic acid derivative (284) from 3-acetamido-3-deoxy-l,2-C -isopropylidene-a-D-ribofura-... 

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