1260153-16-9Relevant academic research and scientific papers
Unusual reactions of (+)-Car-2-ene and (+)-Car-3-ene with aldehydes on K10 clay
Il'Ina, Irina V.,Volcho, Konstantin P.,Korchagina, Dina V.,Salnikov, Georgi E.,Genaev, Alexander M.,Karpova, Elena V.,Salakhutdinov, Nariman F.
, p. 2135 - 2150 (2010)
The reactions of (+)-car-2-ene (1) and (+)-car-3-ene (2) with aldehydes in the presence of montmorillonite clay were studied for the first time (Schemes 3 and 5). The major products of these reactions are optically active, substituted hexahydroisobenzofurans, probably formed as a result of an attack of the protonated aldehyde at the cyclopropane ring. Quite unexpectedly, the products are cis-configured at the ring-fusion site; the fact was established by means of quantum-chemical calculations and NMR data. It appeared that the behavior of the 2 : 3 mixture 1/2 in reactions with aldehydes in the presence of K10 clay differed substantially from the reactivities of the corresponding individual monoterpenes. Copyright 2010 Verlag Helvetica Chimica Acta AG, Zuerich, Switzerland.
Synthesis of isobenzofuran derivatives from renewable 2-carene over halloysite nanotubes
Agabekov, V. E.,Aho, A.,Il'ina, I. V.,Korchagina, D. V.,Kravtsova, A. V.,Li-Zhulanov, N. S.,M?ki-Arvela, P.,Murzin, D. Yu.,Salakhutdinov, N. F.,Sandberg, T.,Sidorenko, A. Yu.,Volcho, K. P.
, (2020/05/08)
Condensation of a terpene 2-carene with 4-methoxybenzaldehyde over a range of acid aluminosilicates including halloysite nanotubes (HNT) was studied for as a model for preparation of isobenzofuran derivatives with a pharmaceutical potential. The catalysts were characterized by FTIR with pyridine, UV by adsorption of 2-phenylethylamine from the aqueous phase, SEM, TEM and N2 physisorption. The largest selectivity to the desired product (ca. 70%) over halloysite nanotubes is associated with weak acidity of these catalysts (45 μmol/g), allowing avoiding side isomerization and condensation reactions. Moreover, the highest yield on air-dry HNT clearly indicates that weak Br?nsted sites favored the reaction. On the contrary, over strong Br?nsted and Lewis acids (Amberlyst-15, scandium triflate), the yield of isobenzofurans did not exceed 16% with formation of mainly 2-carene isomerization products. DFT calculations showed that interactions of the aldehyde with cyclopropane moiety of 2-carene giving isobenzofurans are more beneficial than an alternative direct attack of a proton, leading to side reactions. A possibility to reuse of HNT catalyst was confirmed. Overall, halloysite is a highly effective catalyst for production of isobenzofuran compounds based on 2-carene.
