Δ4-9-Methyloctalin-3,8-dione

Total synthesis of (+/-)-13-methoxy-15-oxozoapatlin, a rearranged kaurane diterpenoid

A 21-step linear synthesis of the structurally novel and biologically intriguing diterpenoid (+/-)-13-methoxy-15-oxozoapatlin (6) is described. Of particular note in this work is the development of a new method for the construction of the functionalized bicyclo[3.2.1]octane unit present in the target substance.

The effect of substitution patterns on the release rates of opioid peptides DADLE and [Leu5]-enkephalin from coumarin prodrug moieties

A coumarin-based prodrug system has been developed in our laboratory for the preparation of esterase-sensitive prodrugs of amines, peptides, and peptidomimetics. The drug release rates from this prodrug system were found to be dependent on the structural features of the drug moiety. The effect of the phenyl ring substitutions on the release kinetics of such prodrugs of model amines was examined recently and it was found that appropriately positioned alkyl substituents on the phenyl ring could help to facilitate the release. Aimed at further understanding the structure-release rate relationship of the coumarin-based cyclic prodrugs, we synthesized and examined a series of substituted coumarinic acid derivatives of opioid peptides, DADLE, and [Leu(5)]-enkephalin.

Biosynthesis of beta-substituted furan skeleton in the lower furanoterpenoids: a model study

Furanoterpenes are widely distributed in the plant kingdom. In this study we have carried out enzymatic synthesis of simple furan compounds from the molecules containing an alpha-isopropylidene ketone unit and the role of cytochrome P450 in this biotransformation has been conclusively established. Eight model compounds (acyclic, monocyclic, and bicyclic, 1-8), having an alpha-isopropylidene ketone unit, were synthesized and incubated with PB-induced rat liver microsomes in the presence of NADPH and O(2). GC-MS and NMR analyses of the product(s) indicated the formation of corresponding furano derivatives (11-18). Cytochrome P450 inhibitors, metyrapone, SKF-525, and carbon monoxide, inhibited the formation of furan (8) to 76, 62, and 97%, respectively. Incubation of dehydrofukinone (7), a naturally occurring terpene, with purified cytochrome P450, NADPH-cytochrome P450 reductase, and dilaurylphosphatidylcholine in the presence of NADPH and O(2) resulted in the formation of 10 and furanodehydrofukinone (19). Based on these observations, we propose one of the probable biosynthetic routes for lower furanoterpenoids in higher plants.