299. The constitution of ascorbic acid

Herbert, R. W.; Hirst, E. L.; Percival, Elizabeth; Reynolds, R.J.W.; Smith, F.

doi:10.1039/jr9330001270

Cited by 195 publications

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“…Chemical conversion of AA to oxalic acid and L-threonic acid, the latter being further oxidized to L-(+)-tartaric acid, constituted one aspect for proof of structure of AA (6). An enzymic mechanism was described for conversion of AA to oxalic acid and threonic acid in the fungus Myrothecium verrucaria (23).…”

Section: Discussionmentioning

confidence: 99%

Metabolism of l-Threonic Acid in Rumex x acutus L. and Pelargonium crispum (L.) L'Hér

Helsper

Loewus²

1982

Plant Physiol.

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L-Threonic acid is a natural constituent in leaves of Pelargonium crispum (L.) L'Her (lemon geranium) and Rumex x acutus L. (sorrel). In both species, L-I'4Clthreonate is formed after feeding L-IU-14Clascorbic acid to detached leaves. R. acutus leaves labeled with L-14-3Hi-or L-16-3Hlascorbic acid produce L-13Hlthreonate, in the first case internally labeled and in the second case confined to the hydroxymethyl group. These results are consistent with the formation of L-threonate from carbons three through six of L-ascorbic acid. Pelargonium crispum shares a common feature with several species of oxalate-accumulating plants in that they cleave the sixcarbon chain of AA3 at the carbon 2/carbon 3 bond with oxalate formation proceeding from the C2 fragment (14, 21). However, they differ in the fate of the C4 fragment. Tartrate is the major C4 product in P. crispum but only a minor one in oxalate-accumulating species such as Rumex crispus (14).Lew surveyed several oxalate-containing species for soluble organic acids (9). Considerable tartrate was found in leaf and stem of Rumex acetosa but not in Rumex crispus. Difficulties encountered in attempts to germinate and grow R acetosa from seed in our laboratory led us to choose a hybrid of European origin, R. x acutus, for our study. This paper demonstrates the role ofthreonate as a common C4 fragment of AA catabolism in P. crispum and R acutus. Further catabolic changes of this C4 acid are also reported. MATERIALS AND METHODSLabeled Compounds. Calcium L-[U-'4C]threonate was prepared from [U-'4CJAA (7) and converted to its ammonium salt or the 1,4-lactone as described by White and Krupka (23 . Glyceric acid and threonic acid were recovered as a combined fraction by anion exchange chromatography. These acids appeared in the eluate ahead of AA. The mixture was converted to trimethylsilyl derivatives and separated by GLC on a column (0.64 cm x 1.8 m) of 3% OV-17 on GasChrom Q. The column was held isothermal at 105°C for 8 min and then temperature-programmed from 105 to 135°C at 3 C/min. The retention time was 6.5 min for GA and 22 min for threonic acid. Recovery and Degradation of Threonic Acid from AA-Labeled Leaves. Threonic acid-containing fractions from the ion exchange gradient were diluted with unlabeled calcium threonate (150 mg) and recrystallized at 4°C from water (2 ml) with methyl alcohol (1 ml). Crystals were rinsed with cold methyl alcohol and dried under reduced pressure. To determine the 3H content of the internal carbons in threonate, 3H-labeled calcium threonate (50 mg) was oxidized to tartaric acid (0.2 ml concn. HNO3 containing 0.16 mg of NaNO2, 60°C, 1 h) (13). Tartaric acid was recovered by passage through a short column of Dowex 50 (H+) exchange resin and conversion into its monopotassium salt (19). To obtain the 3H content on carbon 4 of threonic acid, an aliquot of the calcium salt (16 mg) was oxidized with NaIO4 (107 mg/3 ml 0.33 M sodium phosphate buffer [pH 7.5]). Formaldehyde corresponding to carbon 4 was recovered as the dimedon derivati...

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Section: Discussionmentioning

confidence: 99%

Metabolism of l-Threonic Acid in Rumex x acutus L. and Pelargonium crispum (L.) L'Hér

Helsper

Loewus²

1982

Plant Physiol.

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“…The procedure adopted by us was based on the observation of Herbert et al [1933] th at by heating Z-ascorbic acid with boiling 1 2 % HC1 it readily gave furfuraldehyde which could be determined as the phloroglucide yielding 87% of the theoretical value. As the application of the customary formula for the correction of the solubility of the phloroglucide yielded fictitious results with the quantities of ascorbic acid with which we worked we had recourse to the following empirical method which was found to be sufficiently accurate for our purpose.…”

Section: Determination Of \-Ascorbic Acid As Furfuraldehydementioning

confidence: 99%

63. The resolution of n-propylpropenylcarbinol. The refractivity and optical rotatory dispersion of some substituted allyl alcohols

Arcus¹,

Kenyon²

1938

J. Chem. Soc.

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The Resolution of n-Propylpropenylcarbinol. The Refmctivity andOptical Rotatory Dispersion of some Substituted Allyl Alcohols.B y C. L. A r c u s a n d J. K e n y o n .The resolution of w-propylpropenylcarbinol (y-m ethyl-a-propylallyl alcohol) into its optically active forms, and the properties of som e derivatives of the latter, are -described.Comparison of its molecular refractivity and optical rotatory dispersion is made w ith those of four other optically active substituted allyl alcohols. I t is considered probable th at these alcohols, have the /ra^s-configuration. Evidence is adduced that, although the optical rotatory dispersion of the purely alkyl-substituted allyl i alcohols is complex, th at of the phenyl-substituted allyl alcohols is simple, and it is suggested th at a large proportion of the rotatory power of the latter group of com pounds is due to induced dissym m etry of the phenyl radical.S e v e r a l investigations, dealing with the chemical and optical properties of optically active substituted allyl alcohols, which have arisen from the peculiar behaviour of aydimethylallyl alcohol (I) (Hills, Kenyon, and Phillips, J., 1936, 576) have recently appeared [y-phenyl-a-methylallyl alcohol (II), Kenyon, Partridge, and Phillips, ibid., p. 85; aphenyl-y-methylallyl alcohol (III), idem, J., 1937, 207; ayy-trimethylallyl alcohol (IV), Duveen and Kenyon, J., 1936, 1451] and in furtherance of these studies optically active w-propylpropenylcarbinol (y-methyl-a-w-propylallyl alcohol) (V) has now been examined (I) CHMelCH-CHMe-OH (II) CHPhlCH-CHMe-OH (III) CHMelCH-CHPh-OH (IV) CMe2:CH-CHMe-OH (V) CHMe:CH-CHPra-OH dZ-w-Propylpropenylcarbinol has been described by Reif (Ber., 1906, 39, 1603 and the refractivity of a pure specimen was determined by Auwers and Westermann {Ber.. 1921, 312 ProQuest Number: 10803838All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is d e p e n d e n t upon the quality of the copy subm itted.In the unlikely e v e n t that the a u thor did not send a c o m p le te m anuscript and there are missing pages, these will be noted. Also, if m aterial had to be rem oved, a n o te will ind ica te the deletion. 313 Arcus and Kenyon: The Resolution of n-Propylpropenylcarbinol. 54, 2993). A partial resolution of the alcohol by the fractional crystallisation of the brucine salt of its hydrogen phthalic ester was effected by Levene and Marker (J. Biol. Chem., 1934, 106, 173), but the maximum rotatory power obtained was only some 8% of that now reported.A satisfactory resolution by means of the brucine salt could not be effected, although several procedures were tried. Complete resolution was eventually obtained by fractional crystallisation from dry acetone of the strychnine salt of the hydrogen phthalic ester, followed by fractional crystallisation of the d + dl-and I -f-dl-esters obtained by decom position of the less soluble and the more soluble fractions, respectively, of the strychnine salt. The d-and Z-hydrogen phthalic esters, when hydrolysed with sodiu...

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“…The structure of ascorbic acid has been widely studied [1] and was found to correspond to the enol of 3-keto-D-gulofuranolactone, i.e. it has a lactone structure with an endiol group.…”

Section: Introductionmentioning

confidence: 99%