Hitoshi Takeshita

Mesogenic Properties of Bis(5-Alkoxytropolonato)Metals

Abstract Bis(5-alkoxytropolonato) metallomesogens showed mesogenic properties when the central metal ion was a copper whereas the corresponding zinc complex was not mesogenic. The X-ray diffraction study indicated the mesophases were a smectic B phase and a higher ordered phase such as a crystal B or a smectic G phase.

High-pressure cycloaddition reactions of 3-bromo-1,5-azulenequinone and 3-bromo-1,7-azulenequinone with dienophiles

The high-pressure Diels–Alder reaction of 3-bromo-1,5-azulenequinone and 3-bromo-1,7-azulenequinone with several dienophiles under 300 MPa pressure gave 1∶1 [4xa0+xa02] cycloadducts in good yields. Bromoazulenequinones reacted with dienophiles on the seven-membered ring in such a way as not to produce a cyclopentadienone moiety.

9-Deoxy-15-hydroxy- and 9-deoxy-19-hydroxycotylenol

The title analogs (both C 21 H 34 O 4 ) of cotylenol, a plant-growth regulator, both have a chair-sofa eight-membered ring, which has been recognized as important for the biological activity of this class of compounds.

1-(8,8-Dicyanoheptafulven-3-yl)aza-15-crown-5 ether

The title compound, C 20 H 25 N 3 O 4 , forms a head-to-tail association of two nearly parallel molecules. The bond lengths in the conjugated system indicate a highly polar electronic structure induced by the mesomeric effects of the dialkylamino and dicyano groups.

Photoaddition Reaction of 5,5-Dimethylcyclohexane-1,3-dione with Quadricyclane

The photoproducts identified from dimedone and quadricyclane were not cycloadducts, but the substituted nortricyclane derivatives, being conxad trasting to those from methyl 2,4-dioxopentanoate and quadricyclane. Among the photoproducts obtained from 1 and B, there were products derived from the ketonic tautomer of Band 1. Therefore, it is worth investigating a photoreaction of 1 with other ,B-dikexad tones having more ketonic contribution in the excited state. This in mind, we have investigated the photoaddition reaction of 5,5-dimethylcyclocexane-1,3-dione (2), dimedone, with 1 as described herein. The DV-light irradiation of 2 with excess 1 in ethyl acetate gave a complex mixture, from which 3 to 6 were separated by means of the column chromatography and HPLC. The IH NMR of the major product, 3 (a colorless oil, 13%, IH NMR 0=0.91 (3H, s), 1.12 (3H, m), 1.20 (3H, s), 1.25 (2H, m), 1,28 (lH, t,)=5.5 Hz), 1.78 (lH, dm,)=16.0 Hz), 2.78 (dm,)=16.0 Hz), and 9.24 (lH, s, OOH). l3e NMR 0= 11.2, 11.5, 11.8, 26.0, 30.1, 30.7, 31.2, 32.3, 34.6, 50.9, 52.1, 99.2,203.7, and 204.0. MS m/z, 248 (5),247 (13),205 (10), 153 (13),143 (14),121 (23),93 (lOO), and