Monday, March 1, 2010

conquest of complex natural products seas.

Formation of the ring conquest clues mengkokohkan complex natural products seas.

With the help of crystallization capture reaction, a team led by Phil S. Portrayal of Scripps Research Institute has completed the first total synthesis palau'amine, a sea of natural products has attracted the attention of a group of synthetic chemicals worldwide

Isolated from sponges Stylotella agminata in waters near the Pacific Ocean in the Republic of Palau, is an alkaloid compound palau'amine very impressive. This alkaloid has eight adjacent stereogenic centers and has a large number of nitrogen reactif half. This is also a very large poles, which can make it very complicated to manipulate synthetic intermediate. The challenge to make a structure of this complex has become the intrigues among chemists more than a few decades.

Until now, "hexacyclic ring system previously unheard of palau'amine and poor physical properties have eroded the synthetic effort totaldi several leading laboratories around the world," said Larry E. Overman, an organic chemist at the University of California, at Irvine, who has worked palau'amine family and relatives in pyrrole-imidazole alkaloids.

Greatest chemical challenges of palau'amine is at the core of a very tenuous, that features a unique trans junction between the two rings of five tribes. This feature is one of several recent revisions of palau'amine structure proposed by an international team in 2007 (C & EN, Mar.. 5, 2007, p. 12). Revision is the key in solving this synthetic, but also a variety of synthetic principle which is a typical laboratory cirri Baran. For example, a route to palau'amine, the Scripps team innate reactivity using nitrogen heterocycle, and minimize the use of protective groups (C & EN June 4, 2007, p. 38).

After several attempts to create a tenuous core failed, Baran, a graduate student Ian B. Seiple, researchers postdoktoral Su Shun, and several colleagues tried a different crystallization strategies. They think that the hypothetical molecule with a large ring, they gave diman nickname "macro-palau'amine", directed by crystallization palau'amine along the major ring. Their strategy worked, but they are not up to further investigate this attack lines almost two years.

Overman said that the crystallization step "shows the retrosynthetic analysis of innovative and mechanistic thinking that underpins the success of a series of synthetic amazing total in this field of Baran group."

Scripps team does not make natural products via cyclizations biomimetic proposals, said Daniel Romo of the University of Texas A & M, who is also working on this alkaloid family. "Together - together with their success strategies elegant, this success inspired a question about how if palau'amine can be made naturally."

Baran emphasized that this work unfinished. His team was working on an enantioselective version of this synthetic gram scale in order to obtain the material. Although previous reports on the promising biological activities of palau'amine not yet succeeded completely, these and other structures which are similar to testing a fertile land for several chemical strategies.

Formation of the ring conquest clues mengkokohkan complex natural products seas.

With the help of crystallization capture reaction, a team led by Phil S. Portrayal of Scripps Research Institute has completed the first total synthesis palau'amine, a sea of natural products has attracted the attention of a group of synthetic chemicals worldwide

Isolated from sponges Stylotella agminata in waters near the Pacific Ocean in the Republic of Palau, is an alkaloid compound palau'amine very impressive. This alkaloid has eight adjacent stereogenic centers and has a large number of nitrogen reactif half. This is also a very large poles, which can make it very complicated to manipulate synthetic intermediate. The challenge to make a structure of this complex has become the intrigues among chemists more than a few decades.

Until now, "hexacyclic ring system previously unheard of palau'amine and poor physical properties have eroded the synthetic effort totaldi several leading laboratories around the world," said Larry E. Overman, an organic chemist at the University of California, at Irvine, who has worked palau'amine family and relatives in pyrrole-imidazole alkaloids.

Greatest chemical challenges of palau'amine is at the core of a very tenuous, that features a unique trans junction between the two rings of five tribes. This feature is one of several recent revisions of palau'amine structure proposed by an international team in 2007 (C & EN, Mar.. 5, 2007, p. 12). Revision is the key in solving this synthetic, but also a variety of synthetic principle which is a typical laboratory cirri Baran. For example, a route to palau'amine, the Scripps team innate reactivity using nitrogen heterocycle, and minimize the use of protective groups (C & EN June 4, 2007, p. 38).

After several attempts to create a tenuous core failed, Baran, a graduate student Ian B. Seiple, researchers postdoktoral Su Shun, and several colleagues tried a different crystallization strategies. They think that the hypothetical molecule with a large ring, they gave diman nickname "macro-palau'amine", directed by crystallization palau'amine along the major ring. Their strategy worked, but they are not up to further investigate this attack lines almost two years.

Overman said that the crystallization step "shows the retrosynthetic analysis of innovative and mechanistic thinking that underpins the success of a series of synthetic amazing total in this field of Baran group."

Scripps team does not make natural products via cyclizations biomimetic proposals, said Daniel Romo of the University of Texas A & M, who is also working on this alkaloid family. "Together - together with their success strategies elegant, this success inspired a question about how if palau'amine can be made naturally."

Baran emphasized that this work unfinished. His team was working on an enantioselective version of this synthetic gram scale in order to obtain the material. Although previous reports on the promising biological activities of palau'amine not yet succeeded completely, these and other structures which are similar to testing a fertile land for several chemical strategies.

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