Iminium ion mediated cyclizations of 4-aryl-1, 4-dihydropyridines. Bridging from nitrogen with thiophene and an olefin

GD Hartman, W Halczenko, BT Phillips…

Index: Hartman, George D.; Halczenko, Wasyl; Phillips, Brian T.; Pitzenberger, Steven M. Journal of Organic Chemistry, 1986 , vol. 51, # 12 p. 2202 - 2205

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Citation Number: 3

Abstract

Method B. A mixture of 0.3 g (1 mmol) of 44 and 0.2 mL of triethylamine in 20 mL of CH2C12 was refluxed until solution was complete. The solution was cooled to-5" C and 1.0 mI,(1.3 mmol) of a 10%(v/v) CHzC12 solution of methanesulfonyl chloride was added dropwise. The solution was stirred for 10 min TLC (SiO,; eluent, CHzC12/ether (41 v/v)) indicated the absence of 44, and the solution was cooled to-78" C. By means of a cannula, the solution ...