Seiji Ide

Synthesis and binding properties of calix[4]arene dual porphyrin conjugate: tweezers for DABCO

A dual porphyrin system built on a calix[4]arene spacer was prepared and the corresponding Zn(II) complex 4 showed a marked affinity for 1,4-diazobicyclo[2.2.2]octane (DABCO) as compared with other amines.

Synthesis, conformational studies and inclusion properties of O-benzylated calixarene analogues of trihydroxy[3.3.3]metacyclophanes

O-Benzylation of the flexible macrocycle 1 with benzyl bromide in the presence of NaH in THF under reflux afforded a mixture of two conformers of the tri-O-benzylated products, cone-2a and partial-cone-2a in a ratio of 20∶80 in 80% yield. In contrast, O-alkylation of the triol 1 with 2-(chloromethyl)pyridine in the presence of NaH resulted in exclusive formation of cone-2b. Only when the template metal can hold the 2-pyridyl group(s) and the oxide group(s) on the same side of the [3.3.3]metacyclophane ring, is the conformation immobilized in the cone form. The template effect of the sodium cation plays an important role in this benzylation.The two-phase solvent extraction data indicated that tris(2-pyridylmethoxy)[3.3.3]metacyclophanes 2b show strong Ag+ affinity, high Ag+ selectivity being observed for both cone-2b and partial-cone-2b. 1H NMR Titration of cone-2b with AgSO3CF3 clearly demonstrates that a 1∶1 complex is formed with retention of the original symmetry. The pyridine moiety underwent conformational changes upon Ag+ complexation with the original outward orientation of the ring nitrogen changing to an inside orientation toward the cyclophane cavity.

Synthesis of 5-formyl-17-nitrocalix[4]arenes in the 1,3-alternate conformation

Three 1,3-alternate-5-formyl-17-nitrocalix[4]arenes (4, 5, 7) bearing two propoxyl groups at one side (at 25 and 27 positions) and two benzyloxyl or propoxyl groups at the other side were synthesized.

No scrambling in the synthesis of meso -substituted porphyrins from one dipyrromethane and aryl aldehydes

The cross-condensation of dipyrromethane 1 and aryl aldehydes in the presence of trichloroacetic acid in CH2 Cl2 afforded non-scrambled products in good yields for the first time.

The metal template effect on O -alkylation of hexahomotrioxacalix[3]arene with 4-(chloromethyl)pyridine to afford tris[(4-pyridylmethyl)oxy]hexahomotrioxacalix[3]arenes and their conformational studies

O-Alkylation of the flexible macrocycle 1 with 4-(chloromethyl)pyridine gave di- and tri-O-alkylated products with cone or partial-cone conformation which ratio was affected by NaH or alkali metal carbonates used as a base.

Medium-sized Cyclophanes. Part 42.1Synthesis of [2.n]Metacyclophan-1-ones and[2.n]Metacyclophane-1,2-diones

Acetolysis of 10-endo,11-exo-dibromo-6,14-di-tert-bu tyl-9,17-dimethyl[3.2]metacyclophane cis-3b afforded the corresponding 10,11-diacetoxy derivative cis-5b with retention of configuration, whereas in the case of [4.2]metacyclophane cis-3c the same stereoselectivity was not observed: the diacetoxy derivatives 5 were converted into a 10,11-dione 10b and a 11,12-dione 10c via hydrolysis followed by Swern oxidation of dihydroxy derivatives 7b and 7c.