P-methoxyphenyl group

Infrared and ultraviolet spectra showed the polymers to contain (presumably terminal) p-methoxyphenyl groups. From the Mayo plots (1/DP - [anisole]/[C4H8]) the relative transfer coefficient kjkp was found to be 5.3 x 10"3, a value which did not vary significantly with temperature. The transfer reaction can be represented as follows ... 

At present, we are studying the optimal conditions for the displacement reactions by using different solvents, temperatures, and acids. We have found that variation in the aryl groups also increases the selectivity of dearylation. For example, the p-methoxyphenyl group is displaced by triflic acid much more rapidly than the unsubstituted phenyl ring. 

Conformational factors can determine more than the stereochemistry of rearrangement. In light of Collins findings, let us examine work done earlier by D. Y. Curtin (of the University of Illinois) with 2-amino-1-anisy 1-1-phenyl-1-propanol. This resembles Collins labeled compound (p. 899), except that an anisyl group (p-methoxyphenyl group) takes the place of one of the phenyls. Here, the competition in migration is between a phenyl and an anisyl, instead of between labeled and unlabeled phenyl groups. 

Methylcinnarnic acid (MCA) is a commercially available substrate for which the product ee was only 14% under the original conditions [86], and remained low (23%) after some improvement many years later [94]. However, the application of hydrogen-treated Pd/C under optimized conditions for PCA brought about a notable improvement in the hydrogenation of MCA that resulted in a 46% ee (Scheme 10.13) [100]. The product ee-value was higher with a bulkier a-substituent, while with a P-p-methoxyphenyl group the product ee was 86%. As... 

This group was removed from a cyclic urethane with CAN. It more easily oxidized than the p-methoxyphenyl group. 

Bose and coworkers have reported that the condensation of ethyl biomoacetate with a variety of imines can be completed in a few hours at room temperature by means of ultrasound activation. Oxidative removal of a N-(p-methoxyphenyl) group gave )V-unsubstituted P-lactams, which are useful intermediates in the preparation of p-lactam antibiotics (Scheme 18). 

Formoterol has a (3-directing N-isopropyl-p-methoxyphenyl group and a unique m-formamide and p-hydroxyphenyl... 

N-Benzylhomo-(-)-anisomycin has been synthesized also from tartarim-ide via amidoalkylation followed by introduction of a p-methoxyphenyl group (Schemes 12 and 13) [32,33]. The allylic amide 104 was obtained from tartarimide 103 via cis-amidoalkylation [84]. The amide 104 was subjected... 

It is noteworthy that these correlations are also quite acceptable without the inclusion of any nucleophilic participation terms. The lower a value than for the tert-hvXy halides is partially a temperature effect, but probably also reflects charge delocalization in the leaving tosylate group as well as in the forming carbonium ion (through anchimetric assistance by the p-methoxyphenyl group). 

The p-methoxyphenyl group has recently been found suitable for alcohol protection, as the resulting ethers are stable both to acidic and basic conditions and can be cleaved by brief treatment with ceric ammonium nitrate. The same principle can be applied to carboxylic acid protection.Thus, the rather stable benzyl (64) and phenyl (65) esters can be cleaved as indicated by oxidation with DDQ or cerium(IV)(at pH 3) respectively. A recent total synthesis of (+)-Antimycin-A features the use of a... 

The reaction took 72 hours to complete in 42 °C temperature (Scheme 39.32). After that, one-pot base-mediated cyclization of the product afforded the lactam 113 in 78% yield with 94% ee. Then the p-methoxyphenyl group was removed oxidatively using ceric (IV) ammonium nitrate (CAN) as the oxidant. The synthesis of target molecule 115 from the lactam 114 has already been patented. 

Atkinson, R. S., and R. H. Green 1,5-Hydride Shifts in Acyclic Systems Containing a,p-Unsaturated Ketones and p-Methoxyphenyl Groups. J. Chem. Soc. Perkin I 1974, 394. 

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