反应详情

Prepared essentially as in 29a except that 2-bromo-5-methyl thiophene is used as the starting material. In addition, 1.20 equivalents of lithium diisopropylamide and 1.24 equivalents of 4-(methoxy-methyl-carbamoyl)-piperidine-1-carboxylic acid tert-butyl ester are used for the reaction. Accordingly, stirring time of the reaction mixture may vary. Purification of the residue via flash column chromatography uses a gradient with a mixture of ethyl acetate:n-heptane (1:9) to ethyl acetate:n-heptane (2:8) to yield a yellow oil. LC/MS (ESI), m/e 332 (M−56) and 388 (MH+), retention time 2.15 minutes. Condition II.

1. customPurification of the residue via flash column chromatography
2. additionwith a mixture of ethyl acetate:n-heptane (1:9) to ethyl acetate:n-heptane (2:8)
3. customto yield a yellow oil