1.3.5- Tris cyclohexane-2,4,6-trione

Scheme 11. Chelated structures of cyclohexane- and cyclopentane-1.2.3-trione tris (phenylhydrazones).270 271...

Phloroglucinol, which is regarded as the tri-enol form of cyclohexane-1,3,5-trione, gives the hexahydrate of the corresponding perfluoro-trione upon fluorination in formic acid (Fig. 31) [93] (see 3.1.1.2 for a discussion of the fluorination of carbonyl compounds). 

Cl5H12CI2S, cis-2,2-Dipheny1-3,4-dichlorothietane, 4IB, 409 Cl5H12O3S6, 2,4,6-Tris(1,3-dithiolan-2-ylidene)-cyclohexane-1,3,5-trione, 46B, 361... 

Upon alkaline fusion of lupulone the following acids and ketones have been obtained, in addition to carbon dioxide acetic acid and 5-(3-methyl-2-butenyl)-2,10-dimethylundeca-2,9-dien-6-one 5-methyl-4-hexenoic acid and 3-(3-methyl-2-butenyl)-6-methyl-5-hepten-2-one 2-(3-methyl-2-butenyl)-5-methyl-4-hexenoic acid and 6-methyl-5-hepten-2-one (see also 14.4.). The position of the double bonds in these compounds has been confirmed by ozonolysis, whereby only acetone was isolated, The same result has been obtained by direct ozonization of lupulone (9,10). Consequently, lupulone is the enolized 2-(3-methylbutanoyl)-4,6,6-tris-(3-methyl-2-butenyl)-cyclohexane-1,3,5-trione (23, Fig. 77). The structure has been proved by synthesis (see 11.4.). 

Colupulone was discovered when the hydrogenolysis of hop beta acids afforded a tribenzoate with a melting point of 134°C (11,12). The hydrogenolysis product yielding this particular tribenzoate is 4,6-bis(3-methylbutyl)phlorisobutyrophenone (171, Fig. 78). Oxidation and subsequent alkaline hydrolysis gave dihydrocohumulinic acid (172, Fig. 78). It was deduced that the substrate is 4,6,6-tris(3-methyl-2-butenyl)-2-(2-methylpropanoyl)-cyclohexane-1,3,5-trione (170, Fig. 78) or colupulone, by analogy with cohumulone (8, Fig. 7) (see 2.1.2.). The structure has been confirmed by synthesis (see 11.4.). 

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