Phosphorochloridic acid, diethyl ester

Diethyl chlorophosphate Phosphorochloridic acid, diethyl ester (3,9) (814-49-3)... 

Diethyl chlorophosphate Phosphorochloridic acid, diethyl ester (8,9) (814-49-3) Isoamyl nitrite Nitrous acid, isopentyl ester (8) Nitrous acid, 3-methylbutyl ester (9) (110-46-3)... 

In preparation for the eventual removal of the undesired oxygen function at C-10 of 313 via a Birch reduction, the phenol 313 was phosphorylated with diethyl phosphorochloridate in the presence of triethylamine to give 314, which underwent stereoselective reduction with sodium borohydride with concomitant N-deacylation to deliver the amino alcohol 315. N-Methylation of 315 by the Eschweiler-Clarke protocol using formaldehyde and formic acid followed by ammonolysis of the ester group and acetylation of the C-2 hydroxyl function afforded 316. Dehydration of the amide moiety in 316 with phosphorus oxychloride and subsequent reaction of the resulting amino nitrile 317 with LiAlH4 furnished 318, which underwent reduction with sodium in liquid ammonia to provide unnatural (+)-galanthamine. 

Appropriate quenching of a reductively formed lithium enolate with a carboxylic acid anhydride, chloride, methyl chloroformate or diethyl phosphorochloridate yields the corresponding enol esters, enol carbonates or enol phosphates. These derivatives may be transformed into specific alkenes via reductive cleavage of the vinyl oxygen function, as illustrated by the example in Scheme 8. 

Propyne stirred 1-2 hrs. at room temp, with ethylmagnesium bromide in ether until no more ethane is evolved, added dropwise with stirring at 0° to an ethereal soln. of diethyl phosphorochloridate, stirring continued 1 hr. at 0° and 1 hr. at room temp. diethyl propynylphosphonate. Y 76%. F. e. s. M. S. Chattha and A. M. Aguiar, J. Org. Chem. 36, 2719 (1971) 1-acetylenethionophosphonic acid esters, R-C=C-PS(OR )2, similarly in the presence of a catalytic amount of pyridine s. ibid. 36, 2720. 

Interconversion of Carboxylic Acid Derivatives. Diethyl phosphorochloridate is useful for activation of carboxylic acids toward nucleophilic attack. Subsequent treatment of the phosphate ester with thallium sulfides produced thiol esters." Variations"" on this theme included prior formation of a heterocyclic phospho-nate followed by treatment with alcohols, amines, or thiols, thus providing a racemization-free method to prepare esters, amides, and thiol esters, respectively (eq 9),""" ... 

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