Phenyl ester bond

P)—phenyl ester bond, coupling Sulfide oxidized to sulfone, with... 

P)—phenyl ester bond (p)—o-nitrobenzylester bond (p)—amino acid ester bond... 

A photochemical variant, the so-called photo-Fries rearrangement, proceeds via intermediate formation of radical species. Upon irradiation the phenyl ester molecules (1) are promoted into an excited state 11. By homolytic bond cleavage the radical-pair 12 is formed that reacts to the semiquinone 13, which in turn tautomerizes to the p-acylphenol 3. The corresponding ort/zo-derivative is formed in an analogous way ... 

A. Pentoses.—t-Ascorbic acid 2- and 3-phosphates, together with their phosphate esters, give a characteristic colour with ferric chloride and this colour reaction has been used in a study of the hydrolysis of L-ascorbic acid 3-phosphate (58). The acid-catalysed, pseudo-firsi-order hydrolysis proceeds with P—O bond fission, as does the bromine oxidation of its phenyl ester. Both of these observations can be rationalized if (58) is... 

Some phenyl esters give rise to photodecarbonylation as a side reaction [37], This is also the case for certain phenylpropionamides, which implies cleavage of the CO—C bond in the acyl radical, after the breaking of the N—CO bond [99], If CO—C cleavage occurs prior to N—CO cleavage, then an isocyanate is formed (Scheme 38) and PFR does not occur. 

In addition to ester-linkages, hydroxycinnamic acids can also be covalently linked to cell wall components via phenyl ether bonds. While this has only been demonstrated for wheat (Triticum aestivum L.) straw lignin... 

Although there is evidence that chromone syntheses which proceed by the cyclization of phenyl esters under Friedel-Crafts conditions may involve a Fries rearrangement and hence require the formation of one bond adjacent to the heteroatom, syntheses of chromones from phenols will be considered together in this section. The Simonis reaction (530R(7)l)... 

In 2-trimethylsilylethyl 4-phenylbenzoate 44, the C—Si and C—O ester bonds are in an antiperiplanar conformation, and the C—O ester bond is significantly longer than expected for an alkyl ester bond at a primary centre. This is consistent with a oq si T c o interaction in the ground state. In /raw.v-2-(di methyl phenyl si ly I )cyclohexyl-3,5-dinitrobcnzoate 45, the dihedral angle between the C—Si and C—O ester bonds is found to be just over 60°, and there appears to be little lengthening of the C—O bond. 

A number of functional group can be converted to phenols, e.g. Sulphonic acids and amino groups which have already been mentioned. Phenyl esters can be hydrolysed (Following fig.). Aryl ethers can be cleaved. The bond between the alkyl group and oxygen is specifically cleaved because the Ar-OH bond is too strong to be cleaved. 

The a-cyano-a-naphthyl pyruvic acid ethyl ester shows a hydroxyl band at 3190 cm. 1 which is attributed to chelation (very strong intramolecular hydrogen bonding) (2). At 1717 cm. 1 it gives the a,/3-unsaturated carbonyl band of the enol form (lit. Ref. 2, 1715-1730 cm. 1). The phenyl ester shows the same bands at 3190 and 1717.5 cm. 1, respectively, whereas the thiophene ester spectrum shows intermolecular hydrogen bonding at 3310 cm.-1. Since the a-keto ester carbonyl band of the keto... 

Animals. Rapidly absorbed and also rapidly and almost completely eliminated in urine and feces. Metabolism proceeds via hydrolysis of the ester bond, oxidation of the 2-(6)-methyl group and of the phenyl ring and /V -dealkylation. Residues in tissues were generally low and there was no evidence for accumulation or retention of metalaxyl-M or its metabolites... 

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