The vapor phase de-t-butylation of p-alkylated-1-butylbenzenes, p-halogenated-I-butylbenzenes and p-rbutylanisole were carried out over a commercially obtained silica-alumina catalyst. The surface area of the catalyst and the quantity of pyridine chemisorbed by the catalyst were also measured to obtain the information about the catalyst deactivation.Most of the substituted r-butylbenzenes decomposed to the corresponding substituted-benzene, but p-rbutylcumene and t-butylbromobenzene reacted to the products via complicated networks. In the decomposition of p-alkylated-r-butylbenzenes, thedeactivation coefficients tended to be proportional to the reaction rates, that is, the activity of the catalyst decreased with increasing the rate constants. The introduction of halogeno group to t-butylbenzene caused to decrease the rate of de-1-butylation.The surface areaof the catalyst diminished in progress of the reaction, but the diminishment up to 8% was not responsible lor thedeactivation. The acid site, especially having relatively strong acid strength, decreased in the order of the deactivation coefficients.
Unusual diastereofacial selectivities are observed in the Michael addition reactions of lithiated aminoacetates and -acetamides to α,β-unsaturated carbonyl acceptors. Lithiated (methylamino)acetates and -acetamides show opposite anti- and syn-selectivities, respectively, while lithiated (dialkylamino)acetates and -acetamides are both highly syn-selective.
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