Synthesis and Biological Activities of New HMG-CoA Synthase Inhibitors: 2-Oxetanones with a Side Chain Containing Biphenyl, Terphenyl or Phenylpyridine
“…Terphenyl acids and phospholipid derivatives were synthesized as shown in Scheme . The general synthetic approach is based on methods previously described in the literature. − Specific details of the syntheses are available as Supporting Information. 1 1 2 …”
This paper reports the synthesis of a series of amphiphiles (fatty acids and phosphatidylcholine derivatives)
containing phenyl, biphenyl, and terphenyl chromophores inserted in the hydrocarbon chain and a study
of their self-assembly in Langmuir−Blodgett films and aqueous dispersions. As observed and reported
earlier for amphiphiles containing trans-stilbene, styrylthiophene, or azobenzene chromophores, several
of the biphenyl and terphenyl derivatives show strong evidence of ground state association to form “H”
aggregates characterized by a blue shift in absorption and a structured, red-shifted fluorescence. The
phenyl amphiphiles show different behavior, suggesting that, even for pure films or bilayers, there is very
little or no ground state association. For the biphenyl and terphenyl phospholipids, aqueous suspensions
obtained by sonication are closed bilayer vesicles similar in size to those formed from the corresponding
saturated phospholipids. The overall results of the present study indicate that biphenyl and terphenyl
amphiphiles undergo aggregation processes to form compact arrays formally similar to those observed
with stilbene, tolan, azobenzene, and squaraine derivatives but that the aromatic−aromatic interactions
are considerably weaker than those for the more extended aromatics and lead to less distortion of the
assembly structure.
“…Terphenyl acids and phospholipid derivatives were synthesized as shown in Scheme . The general synthetic approach is based on methods previously described in the literature. − Specific details of the syntheses are available as Supporting Information. 1 1 2 …”
This paper reports the synthesis of a series of amphiphiles (fatty acids and phosphatidylcholine derivatives)
containing phenyl, biphenyl, and terphenyl chromophores inserted in the hydrocarbon chain and a study
of their self-assembly in Langmuir−Blodgett films and aqueous dispersions. As observed and reported
earlier for amphiphiles containing trans-stilbene, styrylthiophene, or azobenzene chromophores, several
of the biphenyl and terphenyl derivatives show strong evidence of ground state association to form “H”
aggregates characterized by a blue shift in absorption and a structured, red-shifted fluorescence. The
phenyl amphiphiles show different behavior, suggesting that, even for pure films or bilayers, there is very
little or no ground state association. For the biphenyl and terphenyl phospholipids, aqueous suspensions
obtained by sonication are closed bilayer vesicles similar in size to those formed from the corresponding
saturated phospholipids. The overall results of the present study indicate that biphenyl and terphenyl
amphiphiles undergo aggregation processes to form compact arrays formally similar to those observed
with stilbene, tolan, azobenzene, and squaraine derivatives but that the aromatic−aromatic interactions
are considerably weaker than those for the more extended aromatics and lead to less distortion of the
assembly structure.
“…15 Omura has described a number of highly active simpler analogues. [16][17][18][19][20] We now report a concise asymmetric synthesis of 1233A (1) from three fragments plus CO 2 (Scheme 1) in which all three stereogenic centres are secured by asymmetric methods.…”
Key steps in a synthesis of the cholesterol biosynthesis inhibitor 1233A include: (a) asymmetric 1,4-reduction of an α , βunsaturated ester using an enantiopure semicorrin (Pfaltz reduction); (b) a Cu(I)-mediated coupling of an iodoalkene and an alkenylstannane to generate a diene; (c) an asymmetric Lewis acid catalysed [2+2] cycloaddition of (trimethylsilyl)ketene to an aldehyde mediated by an enantiopure bis(sulfonamide) ligand.
“…Intermolecular coupling of 2-halopyridines to other aryl halides has attracted considerable interest. Most methods involve a stepwise process in which anions are generated from one aryl halide either through bromo−lithium exchange with n -butyllithium 3 or tert -butyllithium − or Grignard reaction with magnesium metal. , The anions formed are thus quenched with trialkyltin halides to form arylstannanes 3 or exchanged with zinc chloride to form arylzinc halides. − The arylstannanes or arylzinc halides are then coupled with the other aryl halide catalyzed by palladium to form the cross-coupled products. Many functional groups are not tolerated during anion generation.…”
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