An efficient synthesis of O,O- Di Propyl (E)-2-[1-methyl 2-oxopropylidene]phosphorohydrazidothiolate (E) Oxime and Its Analogues: A Potential Marine Toxin

Abstract

An efficient method for the synthesis of Ptychodiscus brevis toxin O,O- di n-propyl (E)-2-[1-methyl 2-oxopropylidene]phosphorohydrazidothiolate (E) oxime (TG-1) and its analogues has been developed using thermally stable and recyclable silica gel and Na₂SO₄ as a condensing agent and water scavenger, respectively. The compounds were evaluated against fish Rasbora daniconius by determining the LC₅₀ and LC₉₀ values. The results of biological evaluation showed that these compounds have high degree of toxicity.

Keywords:

• Fish toxin
• phosphoric acid hydrazides
• ptychodiscus brevis
• thiophosphoric acid hydrazide

Notes

^aIsolated yield

^bDean- Stark receiver was used and reaction was found incomplete in 2 h

^cin ³¹PNMR, a signal of diethyl thiophosphoric acid hydrazide (δ 73.20) disappeared, and a new signal at δ 68.43 appeared in entry 6

^da metal complex formed within 30–45 min

^ethe reaction mixture was refluxed up to 10 h.

^aAll the reactions were performed using equimolar ratios of reactants and the condensing agent in acetonitrile at reflux temperature. The spectral data of all the compounds were found comparable with literature values

^bdiphenyl phosphorohydrazidate was used at the place of diethyl phosphorohydrazidate.

^aIsolated yield

^aIsolated yield, All the above reactions were performed by using 10 mole % of SiO₂-Na₂SO₄ in acetonitrile. The reactions were monitored by silica TLC and ³¹P NMR.

^aThe compound was dissolved in DMSO.