Criticism
In a 2007 paper Phil Baran notes that even though the textbooks state that the use of protective groups is unavoidable and that they are ideally easily added and removed, in practical terms in organic synthesis their use adds two synthetic steps (protection-deprotection sequence) to a chemical sequence and sometimes dramatically lowers chemical yield. Crucially, added complexity impedes the use of synthetic total synthesis in drug discovery. In contrast biomimetic synthesis does not employ protective groups. As an alternative, Baran presented a novel protective-group free synthesis of the compound hapalindole U. The previously published synthesis according to Baran, contained 20 steps with multiple protective group manipulations (two confirmed):
| Hapalindole U Baran 2007 protective-group free | Hapalindole U Muratake 1990 Ts protective groups in blue |
Read more about this topic: Protecting Groups
Famous quotes containing the word criticism:
“It is ... pathetic to observe the complete lack of imagination on the part of certain employers and men and women of the upper-income levels, equally devoid of experience, equally glib with their criticism ... directed against workers, labor leaders, and other villains and personal devils who are the objects of their dart-throwing. Who doesn’t know the wealthy woman who fulminates against the “idle” workers who just won’t get out and hunt jobs?”
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“... criticism ... makes very little dent upon me, unless I think there is some real justification and something should be done.”
—Eleanor Roosevelt (1884–1962)