Tetramethylphosphorodiamidic fluoride

Compound (V) (see p. 88) is a less active inhibitor in vitro than its toxicity might suggest. As has already been pointed out it is a quick-acting poison. Oxidation by permanganate in this case is very slow, but here also an alkali-labile material of increased inhibiting power is produced, but in small yield. 

Compound (V) is used as an insecticide and is marketed as a 50 per cent solution under the name of hanane, which also contains 5 per cent of OJVI.P.A. Hanane properly placed at the roots of cocoa trees kills mealy-bugs in the crown of the tree without harming beneficial insects such as ants which effect pollination. Five hundred trees infested with mealy-bugs were treated 10 per cent of the trees, chosen at random, were cut down before treatment and after treatment, and the number of mealy-bugs counted under a binocular microscope. After 6 weeks only thirty-five mealy-bugs were present on the treated trees as opposed to 42,971 counted before treatment in the untreated portion, a reduction of 99-9 per cent. It is well known that several species of mealy-bug, especially Pseudococcus ujalensis, transmit strains of swollen shoot virus, which kill the cocoa tree in 2-4 years. Thus the spread of the disease can be effectively controlled by this systemic insecticide (see also p. 171). 

This compound was designated E-600 by Schrader, who prepared it by the reaction of sodium p-nitrophenate on diethyl phosphorochloridate in xylene  

It can also be made by nitrating diethyl phenyl phosphate be-low 0°. It is a red oil, almost insoluble in water, and Schrader found it effective against aphids, while Ball and AUen proved it active against the housefly, milkweed bug and cockroach. Later work showed it active against the two-spotted spider mite. 

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Fig. 14. Inhibition of horse-serum cholinesterase by various compounds. Incubated for 15 min. at 20° before addition of 2 mg. of acetylcholine chloride. A, di-isopropyl phosphorofluoridate B, di ec.-butyl phosphorofluoridate C, eserine D, diphenyl phosphorofluoridate E, dithioethyl phosphorofluoridate F, tetramethylphosphorodiamidic fluoride O, diethyl ALmethylphosphor-amidate.

Later, American workers2 described the preparation of this type of compound by a method which necessitated the loss of two-thirds of the fluorine concerned in the reaction. They prepared tetramethylphosphorodiamidic fluoride (bisdimethyl-aminofluorophosphine oxide) (II) by the action of phosphorus oxyfluoride on the calculated quantity of dimethylamine. In addition, it should be emphasized that phosphorus oxyfluoride is a gas and is more difficult than the liquid phosphorus oxydichlorofluoride to manipulate. In Report no. 14 on fluoro-phosphonates to the Ministry of Supply3 it was shown that our reaction could also be applied to the preparation of tetramethyl-... 

It was found that tetramethylphosphorodiamidic fluoride (bisdimethylaminofluorophosphine oxide) was very toxic and had a l.d. 50 of the order of 1-0 mg./kg. for subcutaneous injection into mice the concentration for rabbits was higher at 3 0 mg./kg. (intravenously). The Cambridge figure for toxicity by inhalation agreed with that found by American workers, the L.c. 50 for mice being 0 095 mg./l. for a 10 min. exposure. We also carried out experiments with four human observers exposed to a concentration of one part in a million for 5 min. No effects of any kind were noted in particular, myotic action was absent. In this report, therefore, the highly toxic compound... 

N, N,N,N-TETRAMETHYLPHOSPHORODIAMIDIC FLUORIDE see BJE750 TETRAMETHYLPLUMBANE see TDR500 TETRAMETHYLPYRAZINE seeTDUSOO... 

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