Quinic acid structure

Green coffee beans, as expected, contain storage polysaccharides such as starch, and structural support compounds such as cellulose and lignin. Mono- and di-saccharides are represented, as well as the related compounds quinic acid and myo inositol. 

Hydroxy cinnamic acids are included in the phenylpropanoid group (C6-C3). They are formed with an aromatic ring and a three-carbon chain. There are four basic structures the coumaric acids, caffeic acids, ferulic acids, and sinapic acids. In nature, they are usually associated with other compounds such as chlorogenic acid, which is the link between caffeic acid and quinic acid. 

The remaining shlklmates in Table III also are relatively simple, well known compounds. The phenolic structures of vanillin (125) and gallic acid (127) and the prephenolic structures of the common quinic acid (128) and chlorogenic acid (129) make them candidates for physiological activity. Gallic acid is the monomer for tannins, biological polymers found in the cotton plant (15, 37). 

HexOMe, methyl glycoside Hex-onic, aldohexonic acid hmba, 2-hydroxy-2-methylbutanoate2 HYSCORE, hyperfine sublevel correlation spectroscopy mod. ampl., modulation amphtude polyGalA, galacturonan Qa, quinic acid XAFS, X-ray absorption fine structure spectroscopy... 

Following the structure proof of the alkaloids by degradation, Hughes et al. (.18) synthesized (—)-0-methylcryptaustoline iodide (14) by methods elaborated by Schopf and Robinson. ( )-Laudanosine was resolved by quinic acid (79), and (S)-(-)-laudanosine was 0-demethylated by Schopf s procedure, oxidized by chloranil, and remethylated to afford chiral 14 as the iodide in 40% yield. Their product had the same specific rotation and melting point as O-methylcryp-taustoline iodide obtained from the natural alkaloid 1. Methine derivatives obtained from synthetic and natural compounds had identical optical properties. 

Chlorogenic acids occur ubiquitously in plants. They are esters of hydroxycinnamic acids with quinic acid. The structures of chlorogenic... 

Many other variations of the basic structure 10 have been explored, including an-hydro sugars and carbocyclic analogs, the latter derived from quinic acid 13 [23-26]. In summary, the preparation of these materials (e.g. 14-16) requires more synthetic effort than the fructose-derived ketone 10. Occasionally, e.g. when using 14, catalyst loadings can be reduced to 5% relative to the substrate olefin, and epoxide yields and selectivity remain comparable with those obtained by use of the fructose-derived ketone 10. Alternative ex-chiral pool ketone catalysts were reported by Adam et al. The ketones 17 and 18 are derived from D-mannitol and tartaric acid, respectively [27]. Enantiomeric excesses up to 81% were achieved in the epox-idation of l,2-(E)-disubstituted and trisubstituted olefins. 

Among simple unsaturated carbaaldopyranoses, one of the most well-known examples is represented by MK7607, an effective herbicidal substance isolated from the fermentation broth of Corvularia eragrostidis [38]. Preparation of its unnatural antipode 174 was recently accomplished by Singh who exploited (-)-shikimic acid 169 as the chiral source (Scheme 28) [39]. As with quinic acid, the shikimate structure can be... 

Searching for a simple, divergent methodology to access valiolamine 203 and certain structurally varied relatives, Shing and Wang [59] utilized the unsaturated scaffold 244 whose preparation from quinic acid 159 was already established [60]. 

A clue to the chemistry involved conies from the structure of caffeyl quinic acid, a compound that is present in instant coffee in some quantity. It is usually about 13% of the soluble solids from coffee beans. 

The first two of these pathways were for many years generally postulated, on the basis of structural relations among various natural products and by analogy with known laboratory reactions they received experimental support later. The last pathway was discovered by B. D. Davis in his work with nutritionally deficient, microbial mutants. However, even earlier, when the structures of quinic acid (VII) and shikimic acid were established, their possible functions as intermediates in the biosynthesis of aromatic... 

Many Crv complexes are difficult to crystallize due to their low stabilities in solution. In such cases, XAFS spectroscopy can be used for structural characterization of the complexes (which can be isolated as amorphous solids or snap-frozen in solutions).11 Recently, this method has been applied for the first detailed characterizations of Crv complexes with natural ligands, quinic acid (49c)148 and L-alanine (55).154 The Cr=0 bond lengths in (45)-(57) vary from 1.52 A to 1.61 a.57,58,141-154 The values of Cr—O bond lengths in the complexes, containing only O-donors, can be used for the determination of the oxidation state of Cr by the bond valence sum method.143... 

Two main lines of research were developed in Hermann Fischer s Berlin period of 19 -1932. One was the study of the constitution and configuration of the naturally-occurring quinic acid. The other dealt with the difficult chemistry of the trioses, glyceraldehyde and dihydroxyacetone, and related two-, three- and four-carbon compounds. The first publication on quinic acid, which appeared in 1921, described certain new derivatives of this tetrahydroxycyclohexanecarboxyhc acid but left the position of one of the hydroxyl groups uncertain. Four years later. Professor Paul Karrer and his students used this information, and some additional observations, to propose what appeared to be a satisfactory structural formula for the compound. Fischer, however, was not satisfied with this conclusion and... 

The structural and configurational studies of quinic acid (1) by Fischer and Gerda Dangschat were extended during the Basle period to shikimic acid (2), the trihydroxycyclohexenecarboxyhc acid first isolated from the Chinese star anise by Eykman in 1885. This acid was first proved to be a... 

The discoveries of the isomeric dihydric phenols were as old as that of phenol itself. Catechol,(1,2-benzenediol, 1,2-dihydroxybenzene, o-dihydroxybenzene) was first obtained in 1839 essentially from the dry distillation of tannin. Resorcinol (1,3-dihydroxybenzene), was isolated in 1864 from the alkaline fusion of galbanum, and of asafoetida, resins, repectively from Iranian species of Ferula and Narthex asafoetida. In 1820 hydroquinone was recovered from the dry distillation of quinic acid although it was not investigated structurally until 1844 by Wohler. 

Oxidative interconversion of cyclitols and derivatives into acyclic, di-carboxylic acids has been widely used for structural elucidation in this series. Early applications of the procedure helped determination of the constitution of shikimic and quinic acids for example, cleavage of the 1,2,3-triol grouping of methyl dihydroshikimate (35) produced a dialdehyde (36), which was oxidized with bromine water to the (known) degradation end product, tricarballylic acid (37). This approach to structural problems has proved particularly successful for determining the configuration of glycosides and related compounds. 

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