反应详情

Adapting literature known protocols (Huff et al., Tetrahedron Lett., 1996, 37(12), 3655-3658; Baylis, Tetrahedron Lett., 1995, 36(51), 9385-9388; and Xu, et al., U.S. Pat. No. 8,344,028 (2013)), 5-[2-(2-methyl-5-nitro-phenyl)-3-nitro-propyl]-1-trityl-tetrazole (20b) is prepared from 1-methyl-4-nitro-2-[(E)-2-nitrovinyl]benzene (19a) through 1,4-conjugate addition of lithiated 5-methyl-1-trityl-tetrazole (Huff et al., Tetrahedron Lett., 1996, 37(12), 3655-3658). 5-Methyl-1-trityl-tetrazole (3.92 g, 12.0 mmol) in anhydrous tetrahydrofuran (THF) (15 mL) is lithiated under a nitrogen atmosphere and at a temperature of about −78° C. (dry ice/acetone bath) with n-butyllithium (nBuLi) in hexane (12.0 mL, 12.0 mmol) and added via a cannula to a cooled solution (−78° C.; dry ice/acetone bath, nitrogen atmosphere) of (19a) (2.08 g, 10.0 mmol) in anhydrous tetrahydrofuran (THF) (15 mL). Aqueous work-up and purification by silica gel column chromatography using ethyl acetate (EtOAc) and hexanes mixtures afford the title compound (20b).

1. customAqueous work-up and purification by silica gel column chromatography