Synthesis of sterically hindered aromatic aldehydes
摘要:
Formylation of mesitylene, durene, and m-xylene derivatives containing electron-donor and electron-acceptor substituents by dichloromethyl methyl ether was studied in the presence of TiCl4. A series of functionally substituted sterically hindered benzaldehydes was prepared from the products of these reactions.
Unusual effects of steric hindrances in NMR spectra of o,o′-dialkylsubstituted benzylidene dichlorides
摘要:
It has been found that steric hindrances of the CHCl2 group rotation around C(Ar)-CHCl2 bond in o,o'-dialkylsubstituted benzylidene dichlorides call forth a non-equivalence of the alkyls in positions 2 and 6. The non-equivalence displays in H-1 and C-13 NMR spectra at room temperature and at -20 degrees-C. At the latter temperature, the spectra of 2,4,6-trimethyl-3-chloromethylbenzylidene dichloride and bis(dichloromethyl)mesitylene indicate the presence of two conformations, the assignment of signals having been accomplished for each of them.
Synthesis of sterically hindered aromatic aldehydes
作者:A. P. Yakubov、D. V. Tsyganov、L. I. Belen'kii、M. M. Krayushkin
DOI:10.1007/bf00961246
日期:1991.7
Formylation of mesitylene, durene, and m-xylene derivatives containing electron-donor and electron-acceptor substituents by dichloromethyl methyl ether was studied in the presence of TiCl4. A series of functionally substituted sterically hindered benzaldehydes was prepared from the products of these reactions.
Unusual effects of steric hindrances in NMR spectra of o,o′-dialkylsubstituted benzylidene dichlorides
It has been found that steric hindrances of the CHCl2 group rotation around C(Ar)-CHCl2 bond in o,o'-dialkylsubstituted benzylidene dichlorides call forth a non-equivalence of the alkyls in positions 2 and 6. The non-equivalence displays in H-1 and C-13 NMR spectra at room temperature and at -20 degrees-C. At the latter temperature, the spectra of 2,4,6-trimethyl-3-chloromethylbenzylidene dichloride and bis(dichloromethyl)mesitylene indicate the presence of two conformations, the assignment of signals having been accomplished for each of them.