The Equilibrium between Symmetrical and Unsymmetrical Monoglycerides and Determination of Total Monoglycerides

Martin, James B.

doi:10.1021/ja01118a005

Cited by 97 publications

(32 citation statements)

References 4 publications

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“…In many instances there was insufficient lipid for analyses. Whenever sufficient material was available a portion of the sample was taken up in chloroform, washed with water, dried with anhydrous sodium sulfate, and analyzed for 1-monoglyceride (7,13). Another portion in chloroform was treated with perchloric acid to convert the 2-monoglycerides to 1-monoglycerides, then water-washed, and analyzed for total monoglycerides (13).…”

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confidence: 99%

Digestion of Neutral Fats by Human Subjects 1

Harris¹,

Chamberlain²,

Benedict³

1955

J. Clin. Invest.

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Several theories have been advanced to describe the digestion of fats in animals and in humans. Of these, two have been popular. The hydrolytic theory (1) suggests that triglycerides are broken down completely to fatty acids and glycerol which are then absorbed into the intestinal wall. The particulate theory (2) suggests that triglycerides are partially hydrolyzed in the intestinal lumen to monoglycerides, diglycerides, and fatty acids. The partial glycerides, fatty acids, and bile salts cause a fine emulsification of the remaining triglyceride. This emulsion, containing triglycerides, then enters the intestinal wall.Much indirect evidence exists for the formation of partial glycerides during fat digestion. Reiser, Bryson, Carr, and Kuiken (3) analyzed the lipids recovered from the thoracic ducts of rats fed tagged triglyceride and concluded that the major portion of ingested fat is hydrolyzed to monoglyceride prior to absorption. Frazer and Sammons (4) noted that lipids isolated from the lumen of the intestinal tract of rats had a high hydroxyl value and concluded that monoglyceride was present. Later Frazer (5) reported, without presenting experimental details, that he had found monoglycerides in the intestinal tracts of human subjects. The formation and presence of monoglycerides in the intestinal tract during the digestion of fat has been reported in the dog (6), rat (3, 4, 7-9), cat (10), monkey (8), and man (5, 11).Theoretically the formation of two isomeric monoglycerides is possible when a triglyceride is digested to monoglyceride. It was not until the recent work of Mattson, Benedict, Martin, and Beck (7) that 2-monoglycerides were shown to 1

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confidence: 99%

Digestion of Neutral Fats by Human Subjects 1

Harris¹,

Chamberlain²,

Benedict³

1955

J. Clin. Invest.

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“…In contrast with normal fatty acids known to migrate very quickly [7,8], a-aminoacyl migration appears to be a slow process. Under the experimental conditions, a few hours were required to detect some 2' ~ 3'-LPG isomerization.…”

Section: ' + 3'-l Ysylphosphatidylglycerol Isomerizationmentioning

confidence: 92%

“…However, 2 -+ 1 acyl migration in glycerides has been extensively studied [7][8][9]. Final equilibrium was demonstrated to be at least 90% favorable to the 1 position (primary hydroxyl group) and independent of the nature of the esterfiying residue.…”

Section: ' + 3'-l Ysylphosphatidylglycerol Isomerizationmentioning

confidence: 99%

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Chemical and physicochemical studies of lysylphosphatidylglycerol derivatives. Occurrence of A2′ → 3′ lysyl migration

Tocanne

Verheij

Kamp

et al. 1974

Chemistry and Physics of Lipids

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“…Aliquots, 10 ml, were talien a t suitable time iiltervals and were reacted with potassium iodide and an excess of 0.1 N sodiuin thiosulphate solution (18 …”

Section: Ildonoiodomonodeoxymo~o-0-tosylsz(croe I-lexaacetatementioning

confidence: 99%

A CHROMATOGRAPHIC ANALYSIS OF THE PRODUCT FROM THE TRITOSYLATION OF SUCROSE: CRYSTALLINE 6,6′-DI-O-TOSYLSUCROSE

Lemieux¹,

Barrette²

1960

Can. J. Chem.

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Chromatographic analysis on silicic acid of the so-called "tri-0-tosyls~~crose" which is formed in %yo yield on the reaction of 3 moles of p-toluenes~~lphonyl chloride with 1 mole of sucrose in pyridine a t 0' has shown the substance to contain penta-, tetra-, tri-, and di-0-tosylsucroses in the molar ratios 0.05:0.33:1:1, respectively. Any mono-0-tosylsucrose present in the reaction mixture may have been lost in the isolatio~l of the p r o d~~c t .'l'he cornposition of the product was substantially the same when the reaction was performed a t -18". The chromatogram separated the tritosylates into two subfractions. The major subfraction represented 29% by weight of the original "tri-0-tosyls~~crose" and c o~~l d be converted to lr,2:3,G:3',6'-tria~~hydrosucrose in 77.4% yield. Therefore, the so-called "tri-0-tosylsucrose" can contain only 25-29yo of 11,rJ,6'-tri-0-tosylsucrose. G,G1-Di-0-tosylsucrose crystallized from the di-0-tosylsucrose fraction in 10% over-all yield.Cornpton (1) obtained evidence that prinlary hydroxyl groups can undergo tosylation substantially more rapidly than do the secondary positions in a carbohydrate structure. He obtained yields of 41y0 and 36% of the 6-0-tosyl derivatives on ~nonotosylations of the methyl P-and a-D-glucopyranosides, respectively. These results indicate a difference in reactivity between the primary position and the average secondary position in these compounds in the order of 7. On the other hand, Hockett and Downing (2) found that the hydroxyl groups in 1,2:3,6-di-0-isopropylidene-a-D-glucose and 1,2:3,4-di-0-isopropylidene-a-D-galactose differed in reactivity by a factor of 70. Little is Itnown about the factors responsible for such differences in reactivity. Undoubtedly, non-bonded interactions in the transition state are important and probably ~nainly responsible for the generally greater reactivity of primary positions (3, -1). I t should be noted, for example, t h a t the large difference in reactivity found for the di-0-isopropylidene derivatives of glucose and galactose may be mainly clue to the fact that the 3-hydroxyl group of the glucose derivative is eclipsed with the 4-position. Lemieux and I/IcInnes (3) have recently shown that intramolecular hydrogen bonding also can strongly influence the rate of reaction. Furthermore, little information is available on the relative rates for the tosylatio~l of the starting material and the first product of tosylation. Experience in related fields has shown (6, 7, 8) that this can be a dominant feature of the esterification of polyhydroxy conlpounds with hydrophobic reagents. Thus, when it is considered t h a t the reactivities of both the primary and the secondary hydroxyl groups must vary considerably amongst then~selves, it seems clear that attempts a t preferential tosylations of the primary positions of polyhydroxy conlpounds can be expected to proceed in widely varying yields.Hocltett and Zief reported the preparation (0) of a substance termed "tritosylsucrose" by treatment of 1 ~nole of sucrose with 3 ...

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The Equilibrium between Symmetrical and Unsymmetrical Monoglycerides and Determination of Total Monoglycerides

Cited by 97 publications

References 4 publications

Digestion of Neutral Fats by Human Subjects 1

Digestion of Neutral Fats by Human Subjects 1

Chemical and physicochemical studies of lysylphosphatidylglycerol derivatives. Occurrence of A2′ → 3′ lysyl migration

A CHROMATOGRAPHIC ANALYSIS OF THE PRODUCT FROM THE TRITOSYLATION OF SUCROSE: CRYSTALLINE 6,6′-DI-O-TOSYLSUCROSE

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