Phenyl esters, reaction with

The preparation of chelating surface-active diphosphines proved to be more successful. The BDPP analogue R,R-(9) was synthesized by lithiation of tris[p-(3-phe-nylpropyl)phenyl]phosphine, reaction with (R,R)-2,4-pentane-diylditosylate and subsequent sulfonation with concentrated sulfuric acid [16]. Hydrogenation of the prochiral olefin (Z)-2-(N-acetamido)cinnamic acid ester in a two-phase system (ET0Ac/H20) with Rh complexes derived from R,R-(9) was accomplished with identical selectivity compared with the unsulfonated BDPP and improved reactivity compared with BDPPTS (2). 

Solid Phase Synthesis of Polypeptides. A reaction sequence has been designed for the solid-phase synthesis of a polypeptide esterified at the C-terminus with the phenol functionality in 4-hydroxy-6-mercaptodibenzofuran and resin bound with a disulfide bond (eq 4). There are certain liabilities associated with the method (the lability of the disulfide bond, that of the phenyl ester, cyclization with formation of diketopiperazides after the amine is liberated in the second chain elongation step, etc.). A detailed protocol has been designed to circumvent these issues. i... 

The photo-Fries rearrangement was described as being a rearrangement of phenyl ester entities with their transformation in ortho hydroxy ketones and para hydroxy ketones. The reaction occurs in three steps formation of two radicals, recombination and hydrogen extraction [13-15]. The general implied reactions are depicted in Scheme 5 [2]. 

The thermal decomposition of thia2ol-2-yl-carbonyl peroxide in benzene, bromobenzene, or cumene affords thiazole together with good yields of 2-arylthiazoles but negligible amounts of esters. Thiazol-4-ylcarbonyl peroxide gives fair yields of 4-arylthiazoles, but the phenyl ester is also a major product in benzene, indicating reactions of both thiazol-4-yl radicals and thiazol-4-carbonyloxy radicals. Thiazole-5-carbonyl peroxide gives... 

In an early synthesis a methyl carbonate, prepared by reaction of a phenol with methyl chloroformate, was cleaved selectively in the presence of a phenyl ester. ... 

Some authors use O] instead of cr as the substituent constant in such correlations.) An example is provided by the aminolysis of phenyl esters in dioxane the substrates RCOOPh were reacted with -butylamine, and the observed first-order rate constants were related to amine concentration by = k2 [amine] kj [amine]. The rate constants kz and k could be correlated by means of Eq. (7-54), the reaction constants being p = +2.14, b = + 1.03 (for A 2) and p = -1-3.03,8 = -1-1.08 (for ks). Thus, the two reactions are about equally sensitive to steric effects, whereas the amine-catalyzed reaction is more susceptible to electronic effects than is the uncatalyzed reaction. 

The enamines derived from cyclic ketones give the normal alkylated products, although there is some evidence that unstable cycloadducts are initially formed (55b). Thus the enamine (28) derived from cyclohexanone and pyrrolidine on reaction with acrylonitrile, acrylate esters, or phenyl vinyl sulfone gave the 2-alkylated cyclohexanones (63) on hydrolysis of the intermediates (31,32,55,56). These additions are sensitive to the polarity of the solvent. Thus (28) in benzene or dioxane gave an 80% yield of the... 

The nitrile may best be saponified with methyl alcoholic potash while heating to 190° to 200°C with application of pressure. After the methyl alcohol has evaporated the salt is introduced into water and by the addition of dilute mineral acid until the alkaline reaction to phenolphthalein has just disappeared, the amphoteric 1-methyl-4-phenyl-piperidine-4-carbOxylic acid is precipitated while hot in the form of a colorless, coarsely crystalline powder. When dried On the water bath the acid still contains 1 mol of crystal water which is lost only at a raised temperature. The acid melts at 299°C. Reaction with ethanol yields the ester melting at 30°C and subsequent reaction with HCI gives the hydrochloride melting at 187° to 188°C. 

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