98234-53-8Relevant academic research and scientific papers
Synthesis and Enzymatic Studies of Isoprenoid Thiolo Bisubstrate Analogues
Ramamoorthy, Gurusankar,Phan, Richard M.,Poulter, C. Dale
, p. 5093 - 5100 (2016/07/06)
Chain elongation prenyltransferases catalyze the addition of the hydrocarbon moiety of allylic isoprenoid diphosphates to the carbon-carbon double bond in isopentenyl diphosphate (IPP) in the primary building reactions in the isoprenoid biosynthetic pathway. Bis-O-diphosphate analogues 3-OPP/OPP, 4-OPP/OPP, and 5-OPP/OPP and bis-thiolodiphosphate bisubstrate analogues 3-SPP/SPP, 4-SPP/SPP, and 5-SPP/SPP were synthesized. The analogues 4-OPP/OPP, 5-OPP/OPP, 4-SPP/SPP, and 5-SPP/SPP were excellent competitive inhibitors of avian farnesyl diphosphate synthase with KI = 1.0 ± 0.12 μM, KI = 0.5 ± 0.2 μM, KI = 0.7 ± 0.3 μM, and KI = 2.9 ± 0.27 μM, respectively, whereas, analogues 3-OPP/OPP and 3-SPP/SPP displayed mixed type inhibition with KI = 1.4 μM and KI = 5.5 μM, respectively.
Total synthesis of Japanese Hop Ether using an efficient intramolecular Pauson-Khand reaction
Caldwell, John J.,Cameron, Iain D.,Christie, Steven D. R.,Hay, Alastair M.,Johnstone, Craig,Kerr, William J.,Murray, Anthony
, p. 3293 - 3296 (2007/10/03)
The naturally occurring monoterpene Japanese Hop Ether has been synthesised in 14 steps in an overall yield of 29%. The key step of the synthesis, an intramolecular Pauson-Khand reaction, has been shown to proceed in good to excellent yield under mild N-oxide promotion conditions and with complete retention of alkene stereochemistry (for both cis- and trans-alkenes) in the product cyclopentenone. Georg Thieme Verlag Stuttgart.
Stereocontrolled synthesis of cyclic ethers by intramolecular hetero- Michael addition. 5. Synthesis of all diastereoisomers of 2,3,5,6- tetrasubstituted tetrahydropyrans
Betancort,Martin,Padron,Palazon,Ramirez,Soler
, p. 4570 - 4583 (2007/10/03)
A systematic approach to the enantiomeric synthesis of all possible diastereoisomers of 2,6-dialkyl3,5-dioxytetrahydropyrans is described. The key step in the described methodology is the intramolecular cyclization of enantiomerically enriched (≤95% ee) 7-hydroxy-4-(benzoyloxy)-2,3unsaturated esters. In fused systems, six of the eight diastereoisomers for one enantiomeric series were synthesized using this procedure as a key step. Using those with the suitable stereochemistry, the two left were synthesized by simple chemical transformations: in one case by the basic isomerization of the carbon with the (methoxycarbonyl)methyl substituent or by a Mitsunobu inversion of a secondary alcohol available from the benzoyloxy group, in the remaining one by a consecutive sequence of oxidation and reduction reactions again over the free secondary alcohol. The stereochemistry of the intramolecular hetero-Michael addition leading to 2,3-disubstituted tetrahydropyrans is highly predictable when kinetic conditions (low temperature and sodium or potassium bases) are used and can be rationalized by invoking a model of a chair-like transition state in which the benzoyloxy group is located in the equatorial mode and the stereochemical course of the approach of the α,β-unsaturated ester is controlled by the geometry of the double bond. As a rule of thumb, the cyclization using E double bonds yielded cis-2,3-disubstituted tetrahydropyrans, while (Z)-unsaturated esters yielded the trans compounds. This empirical rule is followed in highly substituted systems, leading to fused 2,3,5,6-tetrasubstituted tetrahydropyrans, with the same absolute configuration in the carbon where the nucleophilic oxygen is located and the one where the benzoyloxy group is located. Those systems having opposite configurations yield the same trans2,3-disubstituted compound. The isomerization under thermodynamic conditions (room or higher temperature with excess of base) of the diastereoisomers with the (methoxycarbonyl)methyl substituent in the axial mode led quantitatively to those in which such a group was located equatorially. The scope and limitations of the method are described in both the synthesis of the unsaturated precursor and the stereochemistry reached in the cyclization step.
Stereocontrolled synthesis of cyclic ethers by intramolecular hetero-Michael addition. 3. Enantiomeric synthesis of highly functionalized and fused tetrahydropyrans
Palazon,Soler,Ramirez,Martin
, p. 5467 - 5470 (2007/10/02)
A methodology based on intramolecular hetero-Michael addition of properly functionalized alkoxy-γ-benzoyloxy-α,β-unsaturated esters for the synthesis of highly substituted and fused poly-tetrahydropyran nuclei of marine polyether toxins with absolute control of all the stereocentres is described.
ENANTIOMERIC SYNTHESIS OF POLYSUBSTITUTED FURANES BY STEREOSELECTIVE INTRAMOLECULAR BROMOETHERIFICATION
Tonn, C. E.,Palazon, J. M.,Ruiz-Perez, C.,Rodriguez, M. L.,Martin, V. S.
, p. 3149 - 3152 (2007/10/02)
The stereoselectively controlled synthesis of 2,5 dialkyl,3-substituted furanes by enantioselective construction of chiral alkenols and stereoselective bromocyclization is described.
Synthesis of 1,2-Dihydropyridines, 2,3-Dihydro-4(1H)-pyridinone, and 1,2,3,4-Tetrahydropyridines via N-Acyl N,O-Hemiacetal Formation
Roduit, Jean-Paul,Wyler, Hugo
, p. 403 - 414 (2007/10/02)
New procedures are described for the synthesis of α,β-ethylenic and acetylenic aldehydes from 2-butene- and 2-butyne-1,4-diol, respectively (see Scheme 1).These are applied to the preparation of a particular δ-acetylamino-α,β-ethylenic aldehyde ((E)-5) as well as of its acetylenic analogue 15.On heating in the presence of a silyl enol ether, the former undergoes a complete dehydrative cyclization affording the N-acetyl-1,2-dihydropyridine 19.The addition of HCl to aldehyde (E)-5 results in the production of the 4-chloro-1,2,3,4-tetrahydropyridine 22 which is hydrolyzed to the corresponding alcohol 23 on silica gel.Similarly, the addition of HCl or HBr to the δ-acetylamino-α,β-acetylenic aldehyde 15 leads to the previously unknown 4-halo-1,2-dihydropyridines 26; these are easily hydrolyzed to the 2,3-dihydro-4(1H)-pyridinone 27.The ring-forming process involves a N-acyl N,O-hemiacetal as intermediate which is eventually dehydrated.
