Synthetic and novel biocatalytic resolution studies on (±)-5/6/7-acetoxy-4-aryl-3,4-dihydrocoumarins
摘要:
Eleven (+/-)-5/6/7-acetoxy-4-aryl-3,4-dihydrocoumarins have been synthesised in two steps starting from the coupling of cinnamic acid/substituted cinnamic acid with appropriate phenols, followed by acetylation in 50-83% overall yields. All hydroxy- and acetoxycoumarins were unambiguously identified on the basis of their spectral data. Candida antarctica lipase-catalysed deacetylation of these racemic acetoxydihydrocoumarins in dioxane occurred with moderate enantioselectivity. This is one of the rare examples of resolution using phenolic ester moiety as a remote handle for chiral recognition by a lipase. (C) 2002 Elsevier Science Ltd. All rights reserved.
Selective Synthesis of 3,4-Dihydrocoumarins and Chalcones from Substituted Aryl Cinnamic Esters
作者:Jae-Ho Jeon、Deok-Mo Yang、Jong-Gab Jun
DOI:10.5012/bkcs.2011.32.1.65
日期:2011.1.20
Coumarins are ubiquitous in plant kingdom and have been used as antitumor, antifungals, anticoagulants, insecticides. Chalcones are also widespread in plant kingdom and have been known to possess diverse biological activities; antibacterial, antifungal, antitumor and anti-inflammatory, etc. As they are considered as important natural products, numerous synthetic approaches have been reported up to the present. We devise a new selective method of preparing dihydrocoumarins and chalcones from aryl cinnamates by the selection of reagents. Dihydrocoumarin derivatives were prepared selectively by using intramolecular cyclization catalyzed by p-toluene sulfonic acid. Also, chalcones were prepared by Fries-rearrangement catalyzed by $TiCl_4$. This method can be used for preparing various coumarin & chalcone compounds.
Solvent-free synthesis of 4-aryl-3,4-dihydrobenzopyran-2-ones via [3+3] cyclocoupling of phenols with cinnamic acid catalyzed by molecular iodine
作者:Durga P. Kamat、Santosh G. Tilve、Vijayendra P. Kamat
DOI:10.1016/j.tetlet.2012.06.069
日期:2012.8
Molecular iodine was used as a catalyst in the [3+3] cyclocoupling of phenols and cinnamicacids which proceeds via a tandem esterification–hydroarylation process at 120–130 °C under solvent-free conditions. Substituted 4-aryl-3,4-dihydrobenzopyran-2-ones were obtained in good yields.
Starkov, S. P., Journal of general chemistry of the USSR, 1983, vol. 53, # 9, p. 1892 - 1898
作者:Starkov, S. P.
DOI:——
日期:——
Molecular iodine catalyst promoted synthesis of chromans and 4-aryl-3,4-dihydrobenzopyran-2-ones via [3+3] cyclocoupling
作者:Mayuri M. Naik、Durga P. Kamat、Santosh G. Tilve、Vijayendra P. Kamat
DOI:10.1016/j.tet.2014.05.093
日期:2014.8
Molecular iodine as an inexpensive catalyst is described in the construction of 2-substituted or 2,2-disubstituted chromans and 4-aryl-3,4-dihydrobenzopyran-2-ones via [3+3] cyclocoupling. For the synthesis of chromans, phenols and allylic alcohols were refluxed in chloroform in presence of 20 mol % I-2 while [3+3] cyclocoupling of phenols and cinnamic acids proceeded to give 4-aryl-3,4-dihydrobenzopyran-2-ones using 30 mol % I-2. Later reaction occurs via a tandem hydroarylation-esterification process at 120-130 degrees C under solvent free conditions. Chromans were obtained in 20-92% yields and substituted 4-aryl-3,4-dihydrobenzopyran-2-ones were obtained in 5-85% yields. (C) 2014 Elsevier Ltd. All rights reserved.