Silver phosphoryl compounds

Silver(diazomethyl)phosphoryl compounds may also be synthesized by treatment of the corresponding diazophosphoryl compound with silver oxide. The thermally stable phosphoryl derivatives undergo electrophilic substitution with alkyl iodides73 but, unlike the carbonyl-substituted derivatives, also undergo electrophilic diazoalkane substitution with a variety of Hiickel aromatic salts (Scheme 1.31).74—79... 

In contrast to diazomethane, a-diazo- S-carbonyl and - S-phosphoryl compounds cannot be halogenated by the direct methods mentioned above, but the corresponding a-mercury-bis(a-diazo-yff-carbonyl) (9.4) or (a-diazo-a-silver-)ff-phosphoryl) derivatives (9.6) must be synthesized first. The metallated compounds 9.4 and 9.6 react with molecular bromine and iodine or with other halogenation reagents, like sulfuryl chloride or cyanogen chloride. The compounds 9.5 and 9.7 are obtained in a yield of 30-90% (Schollkopf et al., 1968, for ethyl diazoacetate Regitz et al., 1979c, for diazophosphoryl compounds). 

Phenanthridine (74) was converted by NBS into the 2-bromo derivative (40%) (55JA6379), but the bromine-sulfuric acid-silver sulfate reagent gave low yields of 1-, 4-, and 10-bromophenanthridines in the ratio (1 6.4 9.5), a reactivity order which contrasts with that found in nitration (1 > 10 > 4 > 2) (69AJC1105). Phosphoryl chloride converted phenanthridine 5-oxide into the 6-chloro derivative, but when that position was blocked by a phenyl substituent, the reductive chlorination process gave a 2-chloro compound (84MI2). 

Compound (1) phosphorylates phosphate monoesters and alcohols, although with the latter a considerable excess of alcohol is necessary to obtain satisfactory yields. In the absence of mercuric ions the milder phosphorylating species (3) can be isolated which converts monoalkyl phosphates to pyrophosphate diesters in good yield but does not react appreciably with alcohols unless catalytic amounts of boron trifluoride are added. Amine salts of (3) are converted to phosphoramidates on heating. In the presence of silver ions, O-esters of thiophosphoric acid behave as phosphorylating agents and a very mild and convenient procedure suitable for preparing labile unsymmetrical pyrophosphate diesters, such as the... 

Synthesis of Phosphoric Acids and Their Derivatives. - A series of monoalkyl and dialkyl phosphorus acid chiral esters have been synthesised for use as carriers for the transport of aromatic amino acids through supported liquid membranes. The compounds acted as effective carriers but enantio-separation was at best moderate. A range of phosphono- and phosphoro-fluoridates have been prepared by treatment of the corresponding thio- or seleno- phosphorus acids with aqueous silver fluoride at room temperature (Scheme 1). In some cases oxidation rather than fluorination occurred. Stereospecifically deuterium-labelled allylic isoprenoid diphosphates, e.g. (1), have been synthesised from the corresponding deuterium-labelled aldehyde by asymmetric reduction, phosphorylation and Sn2 displacement with pyrophosphate (Scheme 2). ... 

Butyrylcholinesterase occurs in the liver and at the motor endplates in muscle fibers and at synapses together with aeetylcholinesterase (Silver 1974). It is estimated that approximately 15% of total cholinesterase activity in the nervous system is due to the nonspecific cholinesterase activity in some of the white matter (Ecobichon and Joy 1982), and the synthesis of this nonspecific cholinesterase occurs in the liver. Several organophosphorus compounds can react and phosphorylate acetylcholinesterase carbamate ester compounds can carbamylate the enzyme, so both can inhibit the acetylcholinesterase. 

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