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:
“Homoeopathy is insignificant as an art of healing, but of great value as criticism on the hygeia or medical practice of the time.”
—Ralph Waldo Emerson (1803–1882)
“A friend of mine spoke of books that are dedicated like this: “To my wife, by whose helpful criticism ...” and so on. He said the dedication should really read: “To my wife. If it had not been for her continual criticism and persistent nagging doubt as to my ability, this book would have appeared in Harper’s instead of The Hardware Age.””
—Brenda Ueland (1891–1985)
“The critic lives at second hand. He writes about. The poem, the novel, or the play must be given to him; criticism exists by the grace of other men’s genius. By virtue of style, criticism can itself become literature. But usually this occurs only when the writer is acting as critic of his own work or as outrider to his own poetics, when the criticism of Coleridge is work in progress or that of T.S. Eliot propaganda.”
—George Steiner (b. 1929)