Potential antifungal activity and structure-activity relationships of some2-amino acid substituted benzo-1,3,2-dioxaphospholene, oxazaphospholine and diazaphospholine 2-ones

Application of various organophosphorus compounds as fungicides and their s tructure-activity relationships have been studied extensively e.g. O,O-bisa ryl alkyl phosphonates (Roy et al. 1996) diaryl dichloromethyl phosphonodit hioates (Roy and Mukejee 1975), and alkyl phenyl (dichloromethyl) phosphona tes (Dureja et al. 1980). Recently, groups of potential fungicides have bee n developed derived from diamines (Havis et al. 1996), o-phenylene-diamines (Khan et al. 1995), and o-aminophenols (Bravo and Late 1996). It was also reported that incorporating an amino acid (Chen et al. 1994) or peptide moi ety in drugs or toxic agents facilitates carrying these chemicals into the cells of the organisms, which leads, in the case of toxicants, to their int racellular accumulation causing cell death (Yadav et al. 1996; Menton et al . 1986). In addition, incorporating an amino acid moiety in toxicants is ex pected to yield nontoxic metabolites upon hydrolysis in plants or soils. Co upling the above information with our desire to develop effective agricultu ral pesticides (Ali and Mostafa 1999; Ismail et al. 1993; Ali and Mohamed 1 999) prompted us to examine the recently reported 2-amino acid substituted benzo-1,3,2-dioxaphospholene, oxazaphospholine and diazaphospholine 2-ones (Ali 1999) as fungicides against Alternaria cucumerina and Fusarium pallido roseum and study their structure-activity relationship.