Pyridinium ylids 4 were generated as reaction intermediates from the decarboxylation of pyridinium betaines 3, which were prepared from the reactions of a-amino acid ester hydrochlorides with 2, 4, 6-triphenylpyrylium...Pyridinium ylids 4 were generated as reaction intermediates from the decarboxylation of pyridinium betaines 3, which were prepared from the reactions of a-amino acid ester hydrochlorides with 2, 4, 6-triphenylpyrylium tetrafluoroborate. Protonation, addition and substitution reactions of 4 with electrophiles were studied in this paper.展开更多
Triphenylpyridinium ylid 2, generated by the decarboxylation of betaine 1, were noted to react with acetyl chloride, chloroform or acetone to form addition-elimination product and proton extraction - carbanion additio...Triphenylpyridinium ylid 2, generated by the decarboxylation of betaine 1, were noted to react with acetyl chloride, chloroform or acetone to form addition-elimination product and proton extraction - carbanion addition products, respectively. The reaction with chloroform was determined as pseudo first order from kinetic experiments. The values of kobsd and t1/2 for decarboxylation at 20, 40 and 50C were calculated to be 4.6 x 10-4, 8.8 x 10-3, 2.8 x 10-2 min-1 and 1.5 x 103, 78, 24 minutes, respectively.展开更多
The reactions of triphenylpyrylium salt 1 with various anuno acids were explored and compared. The reactions with most α-amino acids yielded decarboxylation products 2 via decarboxylation. The reactions with glutamic...The reactions of triphenylpyrylium salt 1 with various anuno acids were explored and compared. The reactions with most α-amino acids yielded decarboxylation products 2 via decarboxylation. The reactions with glutamic acid, lysine and ACC (1-aminocyclopropyl-carboxylic acid) gave triphenylpyndine 8, dimer 9 and acid 5a-acc, respectively. The reactions with βand γ-amino acids yielded triphenylpyridine by intramolecular elinunation.展开更多
基金We want to express our sincere appreciation to Professor Joe Wilson of University of Kentucky and Professor Xiulin Ye of Peking University for their favorable suggestions and assistance for the work.
文摘Pyridinium ylids 4 were generated as reaction intermediates from the decarboxylation of pyridinium betaines 3, which were prepared from the reactions of a-amino acid ester hydrochlorides with 2, 4, 6-triphenylpyrylium tetrafluoroborate. Protonation, addition and substitution reactions of 4 with electrophiles were studied in this paper.
基金the National Natural Science Foundation of China (No. 20272001)
文摘Triphenylpyridinium ylid 2, generated by the decarboxylation of betaine 1, were noted to react with acetyl chloride, chloroform or acetone to form addition-elimination product and proton extraction - carbanion addition products, respectively. The reaction with chloroform was determined as pseudo first order from kinetic experiments. The values of kobsd and t1/2 for decarboxylation at 20, 40 and 50C were calculated to be 4.6 x 10-4, 8.8 x 10-3, 2.8 x 10-2 min-1 and 1.5 x 103, 78, 24 minutes, respectively.
基金the National Natural Science Foundation of China(No.20272001)for financial support.
文摘The reactions of triphenylpyrylium salt 1 with various anuno acids were explored and compared. The reactions with most α-amino acids yielded decarboxylation products 2 via decarboxylation. The reactions with glutamic acid, lysine and ACC (1-aminocyclopropyl-carboxylic acid) gave triphenylpyndine 8, dimer 9 and acid 5a-acc, respectively. The reactions with βand γ-amino acids yielded triphenylpyridine by intramolecular elinunation.
