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727acts similarly to ATP in regard to chelation with The infrared evidence indicates the P-0-P and ^Ilg++ as observed in infrared spectra. However, the purine nucleus are involved in the complex for-Szent-Gyorgyi concludes that chelation with mation with -1Ig++ and that the two former groups l l g t t is possible only with ATP and not with ADP, should be within the same molecule; however, it but the present results suggest that ATP and A4DP does not clearly demonstrate whether the complexform similar types of chelates. since the first and ing is intramolecular or intermolecular. I t is possecond phosphate groups are to both sible that the purine nucleus of one molecule can complex with the P-0-P of another through M g T + XTP and ADP, it suggests that these groups are and still maintain the 1 :1 ratio of Mg++ to nucleoinvolved in the complex formation. I t is interesttide, Either a dimer or a polymer could satisfy divalent cation to transfer the terminal phosphate, not clarify the point. It is hoped that future ina phosphate group6 the divalent cation is again re-complexing is intra-or intermolecular.ing to Point Out that not Only does ATP require a this condition and the present investigation does but in enzymatic reactions in which -ADP accepts quired for the operation. vestigations UTill be able to determine whether the SASKATOOS, SASK., CANAD-4 [COSTRIBUTIOX FROM THE RESEARCH LABORATORIES, ETHYL CORPORATIOS]The synthesis of aryl phosphorodichloridates by the reaction of phenols with phosphoryl chloride is readily catalyzedThe yield of dicliloridate is decreased by the presence of electron-withdrawing substituents such High yields of dialkyl aryl phosphates have been obtained by treating the dichloridate with IVith excess of alkoxide, the product yield is reduced chiefly by an The kinetics of the reactions of dialkyl aryl phosphates and by aluminum chloride. as chlorine in the aryl group. sodium methoxide under controlled PH coriditions. ester interchange reaction which yields trimethyl phosphate. trimethyl phosphates with sodium methoxide and sodium phenoxide are discussed.-Although phosphate esters have been the subject of intensive study for more than a c e n t~r y ,~'~ the preparation in high yield of mixed alkyl aryl phosphates presents a number of problems of interest from a synthetic, kinetic and mechanistic standpoint. Dialkyl aryl phosphates may be synthesized by the reaction of a phenol with a dialkyl phosphorochloridate, (RO)*POCl, or of an alcohol with an aryl phosphorodichloridate, XrOPOC12, usually in the presence of a base or acid acceptor.Of four methods considered? for the preparation of (RO)?POCl, the reaction of an alcohol with phosphoryl chloride was found suitable for the formation of alkyl phosphorodichloridate, ROPOCl?,5,6 but not for the monochloridate. A more attractive route for the latter was stated to involve the reaction sequence 3CnHjOH + PCli + (CnHj0)zPHO + CnHsCl + 2HC1 (CzHjO)?PHO + Cln + (CaHjO)aPOCl + HC1(1)(2) wherein step 1 probably involves cleavage by hydrogen chloride o...

Therefore the indications are that the transitory phosphorylation product is either unstable or remains enzyme-bound. The results presented support the concerted mechanism shown below.