High-performance affinity purification for identification of 15-deoxy-Δ 12,14 -PGJ2 interacting factors using magnetic nanobeads.

Prostaglandin J2 (PGJ2) family have been reported to show various kinds of biological activities. Considerable progress has been made toward understanding the mechanism of adipogenesis, however, the mechanisms of other actions of PGJ2 family remain controversial. The 15-deoxy-Δ(12,14) -PGJ2 (15d-PGJ2) is one of the members of PGJ2 family, and is known as a ligand for peroxisome proliferator-activated receptor γ (PPARγ), which promotes the expression of the crucial genes for adipogenesis. In this study, we found that 15d-PGJ2 did not stimulate PPARγ-mediated gene expression in HEK293 cells whereas 15d-PGJ2 transactivated PPARγ-dependent transcription in other cell lines. Moreover, we confirmed that 15d-PGJ2 suppressed the growth of HEK293 cells. These observations suggest that 15d-PGJ2 shows another biological activity e.g. growth inhibition in HEK293 cells via unknown receptor for 15d-PGJ2. The aim of this study is to develop and validate effective purification system for PGJ2 interacting factors (PGJIFs). We have recently developed high performance magnetic nanobeads. In this study, we have newly developed 15d-PGJ2-immobilized beads by conjugating 15d-PGJ2 to the surface of these nanobeads. Firstly, we showed that PPARγ specifically bound to 15d-PGJ2-immobilized beads. Secondly, we newly identified voltage dependent anionic channel 1 (VDAC1) as new PGJIF from crude extracts of HEK293 cells using this affinity purification system. These data presented here demonstrate that 15d-PGJ2-immobilized beads are effective tool for purification of PGJIFs directly from crude cell extracts.

Construction of a quaternary carbon at the carbonyl carbon of the cyclohexane ring.

High S(N)2' selectivity in the allylic substitution of cyclohexylidene ethyl picolinates with copper reagents prepared from RMgBr and CuBr.Me(2)S was realized by addition of ZnX(2) (X = I, Br, Cl). Furthermore, ZnX(2) accelerated the reaction with the bulky iPr reagent.

2,6-Disubstituted and 2,2,6-trisubstituted piperidines from serine: asymmetric synthesis and further elaboration.

4-Hydroxy-3,4-dihydro-2H-pyridine-1-carboxylic acid benzyl esters, which are readily prepared from serine and terminal acetylenes, undergo Claisen rearrangement to piperidine derivatives when heated with butyl vinyl ether in the presence of Hg(OAc)(2) and Et(3)N. This route to optically pure piperidines having substituents alpha to nitrogen is general, and the rearrangement products are versatile intermediates for making a broad range of amines containing a substituted piperidine subunit.

Total synthesis of the marine alkaloid halichlorine: development and use of a general route to chiral piperidines.

The total synthesis of the marine alkaloid halichlorine is described, based on an approach that involves constructing the fully substituted asymmetric center at an early stage. The five-membered ring is formed by 5-exo-trig radical cyclization and the unsaturated six-membered ring by a process that formally represents a sequential combination of conjugate addition and S(N)2' displacement-a method that is general for making bicyclic compounds with nitrogen at a ring fusion position. A formal synthesis of (+)-halichlorine is also reported, based on the development of a general method for preparing optically pure piperidines. The key step of this method, which was used to make one of our intermediates, is the Claisen rearrangement of a 4-vinyloxy-3,4-dihydro-2H-pyridine-1-carboxylic acid benzyl ester. Such O-vinyl compounds are easily generated in situ from the corresponding alcohols, which are themselves readily assembled from serine and terminal acetylenes.

New general method for regio- and stereoselective allylic substitution with aryl and alkenyl coppers derived from Grignard reagents.

Allylic substitution with sp(2)-carbon reagents (aryl and alkenyl anions) was realized by using allylic picolinates and copper reagents derived from RMgBr and CuBr x Me(2)S to afford anti S(N)2' products regio- and stereoselectively. Steric and electronic factors in the reagents and the size of the methylene substituents around the allylic moiety marginally affected the selectivity. The reaction system was compatible with alkyl reagents as well. Furthermore, the substitution was applied to construction of a quaternary center and synthesis of (-)-sesquichamaenol. Electron-withdrawing nature of the pyridyl group and chelation of the C(=O)-C(5)H(4)N to MgBr(2) generated in situ were found to be responsible for the high efficiency of the substitution.

Picolinoxy group, a new leaving group for anti SN2' selective allylic substitution with aryl anions based on Grignard reagents.

The picolinoxy group was found to be an extremely powerful leaving group for allylic substitution with aryl nucleophiles derived from ArMgBr and CuBr*Me2S. The substitution proceeds with anti SN2' pathway and with high chirality transfer. The electron-withdrawing effect of the pyridyl group and chelation to MgBr2 are likely the origin of success. Results suggesting these effects were obtained.

Mercury-free preparation and selective reactions of propargyl (and propargylic) Grignard reagents.

ZnBr2 was found to catalyze formation of propargyl and propargylic Grignard reagents, and thus put an end to the standard method using a mercury catalyst. The Grignard reagents were submitted to addition reaction with carbonyl compounds and allylation with the cyclic monoacetate to afford the propargyl-type products selectively. Furthermore, the product from the monoacetate was transformed to an acetylene analogue of 2-(5,6-epoxyisoprostane A2)phosphorylcholines.

Nickel-catalyzed coupling producing (2Z)-2,4-alkadien-1-ols, conversion to (E)-3-alkene-1,2,5-triol derivatives, and synthesis of decarestrictine D.

The 3-alkene-1,2,5-triol structure is not only a major framework of biologically important molecules but also a new functional-group-rich unit for synthesis of polyols and sugars. A method furnishing such triol derivatives 8 was developed and successfully applied to synthesis of decarestrictine D (18). First, coupling reaction of the unprotected alcohols 2 with borates 4 was investigated to produce the dienyl alcohols 6 with NiCl2(dppf) in Et2O/THF (5:1) at room temperature. The hydroxyl-group-directed epoxidation of 6 followed by palladium-catalyzed reaction with AcOH (Scheme 1) furnished 3-alkene-1,2,5-triol derivatives 8. Since each step proceeded with high stereo- and regioselectivities, the stereochemistry of 8 has been correlated with the olefin geometry of 6. With the above transformation in mind, synthesis of the full carbon skeleton of decarestrictine D (18) could be designed easily and was completed successfully. Furthermore, a new seco acid 19b with the MOM protective group for the three hydroxyl groups was found to afford macrolide 48 in a yield higher than those reported previously.