Toward the Synthesis of Biologically Important Chlorins, Isobacteriochlorins, and Corrins. Cyclic Enamides from Acetylenic Amides
摘要:
Cyclic enamides 1 of a type useful in the synthesis of naturally occurring chlorins, isobacteriochlorins, and corrins have been prepared by a process involving 5-exo-dig cyclization of the appropriate acetylenic amides 11. The desired cyclization is catalyzed by either n-Bu(4)NF or LiAl-(NHBn)(4).
An improved synthesis of the C,D-ring pyrromethenone of phytochrome and phytochromobilin
作者:Peter A Jacobi、Jiasheng Guo、Sheila I Hauck、Sam H Leung
DOI:10.1016/0040-4039(96)01317-2
日期:1996.8
Pyrromethenone 1b, the C,D-ring segment of both phytochrome (Pr) and phytochromobilin (PΦB) has been prepared in a highly efficient fashion beginning with 2-acetyl-butyrolactone (8). The key steps involved conversion of 8 to the Z-enol triflate 9, followed by Pdo catalyzed coupling with trimethylsilylacetylene, p-chlorophenylselenide ring opening, and amidation, to afford ring-D synthon 11 having the