Trans-nerolidol

The plant is strongly aromatic on account of an essential oil which comprises cis-a-ocimene (25.11%), 3,7-dimethyl-l,6-octadien-3 ol (16.85%), and trans-nerolidol (13.89%), hence the use of the plant in aromatherapy. A methanolic extract of bark of Litsea cubeba (Lour.) Pers. and its fractions (0.01 mg/mL) from bark inhibit NO and PGE2 production in LPS-activated RAW 264.7 macrophages without significant cytotoxicity at less than 0.01 mg/mL concentration. The methanol extract decreased the enzymatic activity of myeloperoxidase (0.05 mg/mL). These findings suggest that L. cubeba is beneficial for inflammatory conditions and may contain compound(s) with anti-inflammatory properties (63). Can we expect the vasorelaxant laurotetanine (64) isolated from the plant to exert such activity ... 

Industrial synthesis of nerolidol starts with linalool, which is converted into ger-anylacetone by using diketene, ethyl acetoacetate, or isopropenyl methyl ether, analogous to the synthesis of 6-methyl-5-hepten-2-one from 2-methyl-3-buten-2-ol. Addition of acetylene and partial hydrogenation of the resultant dehydroner-olidol produces a mixture of cis- and trans-nerolidol racemates. 

Scheme 23.13 Biocatalytic-chemocatalytic reaction sequence to produce a-sinensal from trans-nerolidol. 1 Aspergillus niger sp., Aspergillus niger ATCC 9142, Rhodococcus rubropertinctus DSM 43197 2 chemical conversion steps...

As a further Wittig synthon isopropylidene-triphenylphosphorane was used for the preparation of trans 2,6-famesol and trans-nerolidol 236) which are structurally related to one another like linalool and geraniol. 

The utility of haloboration-conjugate addition sequence has been demonstrated in the selective synthesis of several natural products such as sulcatol, trans-geranylacetone, and trans-nerolidol (Scheme 13.4) [20]. 

Biotransformation of linalool gave both tetrahydrofurans and tetrahydropyranes, but the biotransformation of trans-nerolidol discussed above produced only tetrahydrofurans. A set of homologous dimethylalkadienes were used as substrates to be epoxidized with the fungus Diplodia gossypina. It turned out that dimethylhexa-2,4-diene 53 could not form any tetrahydrofuran probably because the second double bond could not be attacked (Fig. 8). All the other hydrocarbons like 47 and 50 formed the tetrahydrofuran derivative (49 and 52) and sometimes also the tetrahydropyrane compound, but in much lower yields. 

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