Mellein derivatives

Many other mellein derivatives have been found. One of the more common is 5-methylmellein (6). It has been isolated from the almond pathogen Fusicoccum amygdali (ref.48), Hypoxylon and Numularia spp. (ref.49, 50), Phomopsis oblonga (ref.14), Valsa ceratosperma (ref.51), plants of Semecarpus spp. (ref.52), fungus-infected wood (ref. 53), and the heartwood of the Fijian species Euphorbia fidjiana (ref.54). 

A recent synthesis of mellein involves a Diels-Alder reaction, which gives the expected 1,2,3-trisubstituted benzene derivative... 

Figure 4, Preparation of isocoumarin derivatives mellein and 8-methoxyisocoumarin...

A previously identified derivative of mellein, 3,4,6-trihydroxymellein (24), was isolated from the mycelium of a Penicillium found in marine sediment collected in Japan (colorless prisms extraction yield 380 mg/l). This substance, which was also detected in the corresponding culture medium in association with a new compound, acetophtalidin (25), was difficult to extract but could be produced by heating trihydroxymellein in an acid medium [73]. (/ )-5-Methylmellein (21a) has recently been... 

Carpenter R C, Sotheeswaran S, Sultanbawa M U S, Balasubramaniam S 1980 (-)-5-Methyl-mellein and catechol derivatives from four Semecarpus species. Phytochemistry 19 445-447... 

Most of the natural isocoumarins are derived biosynthetically from acetate via the acetate-polymalonate pathway 293, 294). Mellein (19) is formed from acetate and malonate, as in Scheme 3 140). The early reduction of two of the carbonyl groups in the polyketone chain has been indicated by results of CD3COOH feedings ). Loss of the oxygen function at C-6 of an isocoumarin is quite common but loss of the hydroxyl group at C-8 never occurs in those isocoumarins derived from acetate, presumably as a consequence of the cyclization mechanism 293). 

Mellein (19) causes inhibition of growth of corn seedUngs (90) and has been found recently in several insects. The defensive secretion of termites (41) and Australian onerine ants (52), the mandibular gland secretion of carpenter ants (48) and the male hair pencils of the oriental fruit moth (19) all contain mellein (19). There is no evidence that mellein acts as a sex attractant the insect irritant or insecticidal properties of mellein are implicated (121). 8-Hydroxyisocoumarin (14) and its dihydro derivative (13) are found in the defensive secretion of the tem-brionid beetle, Aspena pubescens (175). 

Melanoxin, Y5 Melianone, T51 Melittoside, T15 Mellein, 5-methyl, Y2 Mellein, Y2 Mellitoxin, T31 Meloscine, K31 p-menthane derivatives, T4-5 Menthiafolin, T13 Methofuran, Cl Menthol, A26 Menthone, Cl orrho-menthone, T16 Menthylamine, T4 Menthyl chloride, T4 Mephenesin, All Meroquinene, A32 Mesembrene, K20 Metabolite C, T17 ... 

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