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A double γ-cyclodextrin host bridged with a disulfide bond included two molecules of methyl orange with an association constant (1.06×1011 M−2) which is the largest value ever reported for 1 : 2 (host : guest) bindings of γ-cyclodextrin, demonstrating the collaboration of the two cyclodextrin parts on guest binding.

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1983, 480. DOI:10.1002/anie.198304800

The synthesis and properties of the titled compound (9) are described; (9) was prepared by the thermolysis of the vinyl azide (5) in 70% yield, and no furopyrrole derivatives were formed.

An X-ray structural analysis of all-cis-diepoxy[15]annulenone (1) revealed that (1) exists in two different conformations, each of which possesses a saucer-like three-dimensional geometry, like that of the polyaromatic 14π hydrocarbon corannulene (5).

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1983, 243. DOI:10.1002/anie.198302430

Mercapto[15]annulenone (4) has been prepared from annulenone (2) as a tautomeric mixture with the keto-tautomer (5) in 65% yield; it was found that (4) proved to be diatropic and exists as a rapid equilibrium mixture of (4a) and (4b).

The title compounds were prepared by the Beckmann rearrangement of diepoxy[15]- and triepoxy[17]-annulenone oximes (2) and (11), respectively; 4:7,10:13-diepoxy-1-aza[16]annulene (5) exists as two tautomers, the keto form (5a) and the dipolar form (5b), forming a paratropic 16π system; 3:6,9:12,15:18-triepoxy-2-chloro-1-aza-[18]annulene (12) proved to be strongly diatropic (18π).

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1983, 471. DOI:10.1002/anie.198304710

Mono-trans-hydroxy[15]annulenone (6) forms a keto-enol tautomeric mixture with the keto tautomer (7) in CH2Cl2; (6) was rapidly isomerized into the cis-enol (8) on dissolution in dimethylformamide, dimethyl sulphoxide, and MeOH, indicating that the intramolecular H-bond of (6) is easily broken owing to the motional freedom of the segment on which the OH group was introduced.

A double cyclodextrin host (3b) shows the largest association constant reported for a modified cyclodextrin (Kass.= 2 030 000 mol–1 dm3; with ethyl orange); the greater (×224) degree of association of this guest with (3b) as compared with β-cyclodextrin, demonstrates the full collaboration of the two binding sites.