Potassium phosphoramidate

Condensation of sodium phenoxide witli 2,2,2-trifluoroethyl iodide gives a product of direct substitution in a low yield, several other ethers are formed by eliminatton-addition reactions [7] Use of mesylate as a leaving group and hex amethyl phosphoramide (HMPA) as a solvent increases the yield of the substitution [S] Even chlorine can be replaced when the condensation is performed with potassium fluoride and acetic acid at a high temperature [9] (equations 6-8)... 

Powerful evidence for the intermediacy of a metaphosphorimidate of type 189 nevertheless comes from the product spectrum obtained on reaction of 202 with KOH in ethanol or propanol. The principal products dimethyl sulfide and potassium O-ethyl (or propyl) phosphoramidate can be readily rationalized in terms of the reaction sequence presented in the Scheme 138). 

Ammonium hydrogen phosphoramidate (11.4 g., 0.1 mole) is dissolved in 20 ml. of 50% potassium hydroxide solution and warmed to 50-60° for 10 minutes to expel ammonia. The solution is cooled to 5-10°, neutralized to pH 6 (Alkacid test paper) with glacial acetic acid, and treated with 1 1. of ethanol to precipitate the potassium salt which is filtered with suction, washed successively with alcohol and ether, and air-dried. Yield is 8.1 g. (60%). Anal. Calcd. for KHP03NH2 N, 10.37 P, 22.93. Found N, 10.4 P, 22.7. 

Potassium hydrogen phosphoramidate is a white, crystalline compound that is moderately soluble in water and insoluble in alcohol. The x-ray diffraction2 and infrared absorption3 data have been published. 

In a companion paper Price and Akkapeddi [22] report the kinetics of base initiated polymerization of epoxides in DMSO and hexamethyl-phosphoramide (HMPT). The initiator is potassium t-butoxide. Second order rate coefficients for (R,S)—PO were about double those for (+)—(R) or (—)—(S) monomer. They conclude that the steric factor favouring alternation of isotactic and syndiotactic placement of the t-BuEO also influences PO. Chain transfer to solvent (DMSO) was also studied. For PO polymerization in DMSO they obtain k = 1.5 x 10 exp(—17,200/RT). However, due to some erratic results they are not very confident about the accuracy. In HMPT rates are about three fold faster than in DMSO k = 7.3 X 10 exp(—16,300/RT). Three other epoxides were also studied in HMPT EO, k = 2.75 x 10 exp(-13,300/RT) t-BuEO, fe = 2.0 x 10 exp(-17,100/RT) phenylglycidyl ether (PGE), fc = 5.4 x 10" ... 

The allylic alcohols (23), formed by 1,2-addition of 2-lithiodithians to a,j8-unsaturated ketones, have been shown to undergo [1,3] rearrangement to afford their respective Michael addition products on treatment with potassium hydride in HMPA-THF or tris(pyrrolidinyl)phosphoramide-THF (Scheme 23). Of... 

Milatovic, D., Johnson, M.K., 1993. Reactivation of phosphoramidated acetylcholinesterase and neuropathy target esterase by treatment of inhibited enzyme with potassium fluoride. Chem. Biol. Interact. 87, 425-430. 

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