Novel “one-pot” preparation of tetrahydrobenzodipyran-4-ones. Application to the synthesis of precocene analogues with condensed dihydropyran rings
作者:F. Camps、O. Colomina、J. Coll、A. Messeguer
DOI:10.1016/0040-4020(82)85025-4
日期:1982.1
A novel one-pot preparation of tetrahydrobenzodipyran-4-ones 5 and 6 involving the sequential condensation of resorcinols 7 with 3,3-dimethylacrylic acid (8) and 1,3-methylbutane (10) in the presence of methansesulphonic acid (which acts as solvent and catalyst) and further conversion of tetrahydrobenzodipyran-4-ones to the corresponding dihydrobenzodipyrans 3 and 4, which are precocene analogues,
Regioselective synthesis of substituted pterocarpans and pterocarpenes. Lewis acid Ti (IV) promoted formal (3+2) cycloaddition reactions.
作者:Modachur G. Murugesh、Kandasamy Subburaj、Girish K. Trivedi
DOI:10.1016/0040-4020(95)01052-1
日期:1996.2
A synthesis of novel pterocarpans (8a–e, 10a–c and 11a–e) and pterocarpenes (7a–d and 9a–c) has been carried out. This method involves the Lewis acid Ti (IV) promoted formal (3+2) cycloaddition reaction of 2-alkoxy-1,4-benzoquinones (6a–c) with appropriately substituted 2H-chromenes (1a–b, 2a–b and 5) at −78°C.
ZnCl<sub>2</sub>Promoted Formal (3+2) Cycloaddition Reactions of 2-Alkoxy-1,4-benzoquinones with 2<i>H</i>-Chromenes
作者:Kandasamy Subburaj、Modachur G. Murugesh、Girish K. Trivedi
DOI:10.1080/00397919608005223
日期:1996.8
Abstract A simple, mild, inexpensive and highly efficient method for the synthesis of 2,2-dimethyldihydropyranopterocarpans (4a–h and 5a–b) by formal (3+2) cycloadditionreactions of 2-alkoxy-1,4-benzoquinones (3a–b) with 2H-chromenes (1a–d and 2) using ZnCl2 at room temperature has been developed.
Microwave-Assisted Rate-Enhanced Method for the Synthesis of 2,2-Dimethyl-2<i>H</i>-chromenes
作者:Kandasamy Subburaj、Girish K. Trivedi
DOI:10.1246/bcsj.72.259
日期:1999.2
Herein we describe a simple and facile method for the synthesis of chromenes by base catalyzed condensation of phenols with 3-methyl-2-butenal under microwave irradiation.