Yoshimasa Fukazawa

Azulenophanes V synthesis and physical properties of [2](5,7)azuleno[2]para- and metacyclophanes

Abstract The title compounds 3 and 4 were synthesized by the usual dithia[3.3]phane coupling and photodesulfurization route. Investigation of their physical properties established their molecular dimension and conformation. Transannular interaction disclosed by their electronic spectra was explained by MO calculations.

[4](2,7)troponophane

Abstract The title compound 5 and its dehydro analog 6 were synthesized from 10 and 9, respectively, and their physical properties were examined. Tropone ring in these compounds are deeply bent to tub shapes and conjugation of the carbonyl group is greatly reduced.

Distorted tropones—[3]- and [4](2,7)troponophanes with an extra ethano bridge

Four distorted tropones with bicyclic bridges were synthesized and their structures and physical properties investigated. They represent most distorted examples of tropone and exhibit abnormalities in various spectra and the decarbonylation reaction.

Naphtho[1,8-ab:4,5-a′b′]diazulene, the first nonalternant isomer of dibenzopyrene

Abstract The title compound was synthesized by the transannular reaction of [2.2](1,3)azulenophane and subsequent dehydrogenation. It exhibits characteristic electronic absorption bands extended to near IR region (~1400 nm) and its PMR spectrum indicates the presence of large ring current. MO calculations suggest no bond alternation in the entire π system.

Structures of xantholides A and B, two new guaianolides from xanthium canadense mill.

Abstract The structures of xantholides A and B were deduced on the basis of IR and NMR spectra, and confirmed by X-ray analysis. Xantholide A inhibited the larval growth of Drosophila melanogaster.

[2]Paracyclo[2](3,7)-p-tropoquinonophane

Abstract The title compound 1 a novel cyclophane containing p-tropoquinone, was synthesized starting from 5-methoxytropolone and its physical properties were discussed comparing with those of 3,7-dimethyl-p-tropoquinone and p-benzoquinonophane. The reduced quinone character exhibited by 1 was ascribed to the intramolecular CT interaction and the deformation of the quinone ring.

Azulenophane VI. Conformation of dithia[3.3]azulenophanes

Abstract Conformation of seven dithia[3.3]azulenophanes was investigated by PMR spectroscopy to disclose the presence of syn forms for all cases. This was attributed to the tortional strain in bridges. The syn/anti ratio is also affected to minor extent by the intramolecular dipole-dipole interaction between two dipolar aromatic rings.

[3]Parycyclo− and [3]metacyclo[3](3,7)-p-tropoquinonophanes

Abstract The title phanes were synthesized. Examination of their physical properties including X-ray crystallography disclosed that 1) the p-tropoquinone ring is still bent in both compounds though to a lesser extent than in the corresponding [2.2]phanes, 2) the metacyclo compound prefers syn conformation in solution, and 3) the intramolecular CT interaction is very similar in two compounds.

Formation and rearrangement of tricyclo[7.1.1.04,10undeca-2,4,6,8-tetraen-10-ol, novel pathway from bicyclo[4.4.1]undeca-1(10),2,4,8-tetraen-11-one to 4-methylazulene

Abstract By the action of LDA bicyclo[4.4.]udeca-1(10),2,4,8-tetraen-11-one was found to undergo transannular cyclization to form a unique tricyclic hydroxydihydroazulene which cleaves a CC bond by [π8s+σ2s] electrocyclic process and eventually give 4-methylazulene.

A bridged triptycene-intramolecular diels-alder reaction of 16,19-dimethoxy-[2](9,10)anthraceno[2]paracyclophane

Abstract A bridged triptycene was obtained by intramolecular cycloaddition reaction of 16,19-dimethoxy[2](9,10)anthraceno[2]paracyclophane followed by acid-catalyzed elimination of methanol. Internal strain in this molecule was disclosed by X-ray crystallographic analysis.