Synthesis of inhibitors of 2,3-oxidosqualene-lanosterol cyclase: conjugate addition of organocuprates to N-(carbobenzyloxy)-3-carbomethoxy-5,6-dihydro-4-pyridone.
摘要:
Synthesis of ammonium ion analogues of the first cationic intermediate, 5, presumed to be formed during the cyclization of 2,3-oxidosqualene by 2,3-oxidosqualene-lanosterol cyclase are reported. The required 2,3-substituted-4-piperidinols are prepared by conjugate addition of higher order alkyl (2-thienyl)(cyano)cuprates to 1-(carbobenzyloxy)-3-carbomethoxy-5,6-dihydro-4-pyridone. The nitrogen protecting group (carbobenzyloxy) is key to the synthesis in that it allows the conjugate addition to proceed in high yield and is easily converted to the required N-methyl group in the final products. The key terpenoid side chain appended to C-2 of the piperidinols was constructed from homofarnesyl bromide and 1,5-difunctionalized homoisopentenyl derivatives prepared by zirconium-catalyzed carboalumination of protected 1-butyn-4-ol.
Synthesis of inhibitors of 2,3-oxidosqualene-lanosterol cyclase: conjugate addition of organocuprates to N-(carbobenzyloxy)-3-carbomethoxy-5,6-dihydro-4-pyridone.
摘要:
Synthesis of ammonium ion analogues of the first cationic intermediate, 5, presumed to be formed during the cyclization of 2,3-oxidosqualene by 2,3-oxidosqualene-lanosterol cyclase are reported. The required 2,3-substituted-4-piperidinols are prepared by conjugate addition of higher order alkyl (2-thienyl)(cyano)cuprates to 1-(carbobenzyloxy)-3-carbomethoxy-5,6-dihydro-4-pyridone. The nitrogen protecting group (carbobenzyloxy) is key to the synthesis in that it allows the conjugate addition to proceed in high yield and is easily converted to the required N-methyl group in the final products. The key terpenoid side chain appended to C-2 of the piperidinols was constructed from homofarnesyl bromide and 1,5-difunctionalized homoisopentenyl derivatives prepared by zirconium-catalyzed carboalumination of protected 1-butyn-4-ol.
Amidrazone and Amidoxime Inhibitors of Squalene Hopene Cyclase
作者:Bruce Ganem、Yaohua Dong、Yi Feng Zheng、Glenn D. Prestwich
DOI:10.1021/jo990237h
日期:1999.7.1
The cyclization of squalene catalyzed by the enzyme squalene-hopene cyclase (SHC) leads to the hopanoid family of pentacyclic triterpenes, which are widely found in bacteria as membrane constituents. SHC mediates a cascade of regio- and stereoselective cyclizations that has triggered considerable interest in understanding the enzyme's mechanism of action. This paper reports synthetic studies leading to the preparation of trienylamidrazone 8, trienylamidoxime 9, and tetraenylamidoxime 10 corresponding to a partially cyclized squalene chain. All three compounds displayed significant levels of inhibition when assayed against SHC, with 9 being more active than 8, and amidoxime 10 being the most potent. Detailed profiles of their inhibition kinetics are also presented.
Synthesis of inhibitors of 2,3-oxidosqualene-lanosterol cyclase: conjugate addition of organocuprates to N-(carbobenzyloxy)-3-carbomethoxy-5,6-dihydro-4-pyridone.
作者:Dharmpal S. Dodd、Allan C. Oehlschlager
DOI:10.1021/jo00036a008
日期:1992.5
Synthesis of ammonium ion analogues of the first cationic intermediate, 5, presumed to be formed during the cyclization of 2,3-oxidosqualene by 2,3-oxidosqualene-lanosterol cyclase are reported. The required 2,3-substituted-4-piperidinols are prepared by conjugate addition of higher order alkyl (2-thienyl)(cyano)cuprates to 1-(carbobenzyloxy)-3-carbomethoxy-5,6-dihydro-4-pyridone. The nitrogen protecting group (carbobenzyloxy) is key to the synthesis in that it allows the conjugate addition to proceed in high yield and is easily converted to the required N-methyl group in the final products. The key terpenoid side chain appended to C-2 of the piperidinols was constructed from homofarnesyl bromide and 1,5-difunctionalized homoisopentenyl derivatives prepared by zirconium-catalyzed carboalumination of protected 1-butyn-4-ol.