Reactions of Verbenol Epoxide with Aromatic Aldehydes Containing Hydroxy or Methoxy Groups in the Presence of Montmorillonite Clay

Abstract

The reactions of (−)‐cis‐verbenol epoxide with a number of aromatic aldehydes containing OH and/or MeO groups in the presence of montmorillonite K10 clay have been studied. Several new O‐containing heterocyclic compounds with different frameworks, including compounds with a previously unknown octahydro‐2H‐4,6‐(epoxymethano)chromene framework, have been synthesized. Introduction of one donor substituent in the benzaldehyde molecule led to a decrease in the total yield of intermolecular by formed products, while the introduction of two and more substituents led to an increase in the yield of these products.

Effect of Bio‐Based Aldehyde Structure on the Conversion and Selectivity Towards Glycerol Acetal Over Amberlyst‐46 by Using a Solvent‐Free Approach

“…Similar pattern with drastic decrease in conversion and improved selectivity by p-anisaldehyde has also been reported by others. [43] This reduced reactivity is due to the introduction of an electron donating group on para position on the aromatic ring [44] of the aldehyde rendering the electrophilic site. [45] This hypothesis is supported by higher conversion reported in glycerol acetalization with aromatic aldehyde substituted with electron withdrawal group.…”

Effect of acid modification of kaolin and metakaolin on Brønsted acidity and catalytic properties in the synthesis of octahydro-2H-chromen-4-ol from vanillin and isopulegol

“…The catalytic application of acid-activated clays has been reported for several reactions, such as isomerization [1,5], alkylation [6,7], acylation [8] and various transformations of terpenoids [9,10]. Recently, acid-activated clays were suggested as catalysts for the reaction of homoallylic alcohols with aldehydes (variant of the Prins cyclization reaction) which is one of the routes for the synthesis of a wide range of tetrahydropyran derivatives [11][12][13][14]. Montmorillonite clays have been generally the most popular catalysts for this type of reactions.…”

N-Heterocyclic borneol derivatives as inhibitors of Marburg virus glycoprotein-mediated VSIV pseudotype entry

“… 16 Here, we screened over 170 natural derivatives in a Marburg glycoprotein-mediated VSIV pseudotype system. The library of natural compounds includes the derivatives of (+)-camphor, 17 , 18 (–)-borneol, 19 , 20 dehydroabietylamine, 21 , 22 para -mentha-1,8-dien-5,6-diol, 23 – 26 (–)-isopulegol, 27 deoxycholic acid, 28 (+)-usninic acid, 29 aminoadamantane 30 , 31 and azaadamantane 32 which were previously described by our colleagues. Among the tested derivatives, the bornyl ester containing saturated N-heterocycles exhibited the highest antiviral activity with several hit compounds identified.…”