Stability, Toxicity, and Reaction Mechanism with Esterases of Certain Carbamate Insecticides

Degradation of carbamate herbicides in soil

“…Earlier observations by Casida and Augustinsson (1959) indicated the site of attack on N-methylcarbamates was at the ester rather than the amide bond, since both I-naphthyl and p-nitrophenyl N-methylcarbamate and the acetate of 1-naphthol orp-nitrophenol were cleaved by albumin. Products resulting from a n initial attack at the ester linkage would probably be the enol, carbonate ion, and alkylamine, with methylisocyanate as a possible intermediate according to Aeschlimann and Reinert (1931) and Casida et al (1959Casida et al ( ,1960. Methylcarbamic acid also might be formed a s an intermediate, rather than the methylisocyanate.…”

The Electronic Structure of Carbamate Derivatives as the Inhibitors of Cholinesterase

“…We calculated the total it electron density and the superdelocalizability for a nucleo philic reactivity on various positions of several substituted phenyl N-metyl carbamates and found that the total it electron density of the ethereal oxygen atoms and, though in the lesser degree, that of the carbonyl oxygen atoms had almost linear correlation with the house-fly brain cholinesterase inhibitory potency observed by Kolbezen et al There have been some indications that the binding of some of the phenyl carbamates such as prostigmine requires the basic group in the esteratic site of the enzyme (14), and furthermore, that some of the carbamates might form the carbamoyl derivatives of the cholinesterase at its esteratic site (5,11,12,(15)(16)(17)(18) in a manner similar to that in which the dialkyl phosphates phosphorylate the enzyme.…”

DIE WIRKUNG KOMBINIERTER ANWENDUNG INSEKTIZIDER PHOSPHORSÄUREESTER UND CARBAMATE AUF DROSOPHILA MELANOGASTER1

“…• ~ 60- .~ 40" AUGUSTINSSON • JOHNSSON 1960, CASIDA 1963. ES konnte je,d,och auch eine der Phosphorylierung der AChE entsprechende Carbamylierung bei Electrophorus electricus nachgewiesen werden, die durch Hydroxylamin aber nicht durch 2-PAM (Pyridin-2raldoxim methyljodid) reaktiviert werden konme (WILSON, HATCH & GINSBURO 1960).…”