Pictet-Spengler condensation of N-sulfonyl-β-phenethylamines with α-chloro-α-phenylselenoesters. New synthesis of 1,2,3,4-tetrahydroisoquinoline-1-carboxylates
作者:Claudio C. Silveira、Carmem R. Bernardi、Antonio L. Braga、Teodoro S. Kaufman
DOI:10.1016/s0040-4039(99)00958-2
日期:1999.7
The reaction of N-sulfonyl-β-phenethylamines with α-chloro-α-phenylseleno acetate/propionate esters under Lewis acid promotion gives moderate to good yields of the corresponding 1,2,3,4-tetrahydroisoquinoline-1-carboxylates. Varying degrees of diastereoselection were obtained using chiral sulfonamides and/or esters. Employing this strategy, the achievement of a new total synthesis of Calycotomine is
The cis/trans ratio as well as trans-(−)-(R:R)/(+)-(S:S) ratio of cyclopropane products in the NaH-catalyzed Michael type condensations of (−)-menthyl chloropropionate with methyl methacrylate, conducted in media of varying dielectric constant, unequivocally showed the dependence of stereoselectivity of the reaction on solvent polarity. The stereochemical results were explicable in terms of electrostatic
synthesized and evaluated for their antibacterial activity against Gram-positive Staphylococcus aureus and Bacillus subtilis and Gram-negative Escherichia coli and in vitro antifungal activity against Candida albicans and Aspergillus niger. The results of antimicrobial activity demonstrated that the compounds 10, 20, and 21 were the most active ones among the synthesized compounds. The QSAR studies revealed
Absolute Configurations of α-Substituted Glycidates. (−)-(<i>R</i>)-Ethyl 2-Methyl-1-oxaspiro[2.5]octane-2-carboxylate and (−)-(<i>R</i>)-Ethyl 2,3-Dimethyl-2,3-epoxybutanoate