Search

The reactions of a series of phosphylating agents (RR'P(O)X) with ethanolamine have been examined, and relative yields of the products from the nucleophilic amino and hydroxyl moieties determined. In general the amount of O-phosphylation increased as R and R' were changed from dimethylamino through alkoxy to methyl and as the leaving group (X) was changed from OP(O)RR' TO CN. The only exceptions occurred when R was dimethylamino and X was Cl. When X was F, only O-phosphylation was observed. Thus, a wide range of essentially continuously varying selectivities was found. The results are discussed in terms of the amount of charge transfer involved in the formation of the transition state which is assumed to be determined by the electrophile. When the charge transfer is small, the contributions to the activation energy of such factors as solvation and ionization potential of the nucleophile are most important, resulting in N-phosphylation. As the amount of charge transfer increases, the energy of bond formation becomes the dominant factor and O-phosphylation is preferred. (Author), Presented at meeting of the Chemical Institute of Canada (52nd) Montreal, Quebec. May 1969.

The kinetics of the hydrolysis of N,N-dimethyl-2-phenylaziridinium ion (DPA) have been studied over the pH range 5.5-8.0 as have the kinetics of the interaction of DPA with bovine erythrocyte acetylcholinesterase. The enzyme is initially inhibited reversibly and subsequently irreversibly towards acetylcholine hydrolysis. Between pH values of 6.0 and 8.0 the kinetics of the irreversible inhibition are consistent with either of two kinetically indistinguishable mechanisms, one involving transformation of the initial reversible complex and the other an independent attack on the uncomplexed enzyme. The first mechanism gives rise to a first-order rate constant which is comparable with that for the hydrolysis of DPA but which increases with decreasing pH; an acidic group on the enzyme with pK(a) between 6.0 and 7.0 may be involved. The second-order rate constant arising from the second treatment goes through a maximum at pH 7.3. At pH 5.5 the kinetics are not consistent with either mechanism. (Author)

When N-(2-methylsulfonylphenyl)hydroxylamine was treated with dilute sodium hydroxide solution the major product was always 2,2'-di(methylsulfonyl)azoxybenzene (1). At room temperature other significant products were 2-hydroxy-2'-methylsulfonylazoxybenzene (2) and 2-methylsulfonylnitrobenzene (3), while (2) was also formed at reflux together with small amounts of 2-hydroxy-2'-methylsulfonylazobenzene, 2-methylsulfonylaniline (4), 3-methylsulfonyl-3'-nitro-4-amino-4'-hydroxybiphenyl, and (3). The compounds (1), (2), and (4) were also obtained when 2-methylsulfonylnitrosobenzene (4) was boiled with alkali. The decomposition of N-(4-methylsulfonylphenyl)hydroxylamine in dilute alkali at room temperature gave a quantitative yield of 4,4'-di(methylsulfonyl)azoxybenzene (5) and at reflux, mixtures of (5) and 4,4'-di(methylsulfonyl)azobenzene were obtained. The modes of formation of the various products from the two hydroxylamines are discussed. (Author)

The preparation of some p-(omega-dimethylaminoalkyl)- and p(omega-dimethylaminoalkoxy)-2oximinoacetophenones and their methiodides is described. No general method was found for synthesis of shortchain (Co, C1, C2) p-(omega-dimethylaminoalkyl)-2oximinoacetophenones. The longer-chain compounds (C3, C4) were prepared by a method which would appear to be general. Omega-Phenyl-1-haloalkanes undergo Friedel-Crafts acylation to yield p-(omega-haloalkyl)acetophenones. These were converted to the dimethylamino compounds, which, subsequently, yielded 2oximinoacetophenones. No method of preparation of p-(2'-dimethylaminoethyl)-2-oximinoacetophenone was found. Synthesis of p-(omega-dimethylaminoalkoxy)-2oximinoacetophenones was accomplished using mixed alpha,omega-dihaloalkanes and p-hydroxyacetophenone. The p-(omega-haloalkoxy)-acetophenones from these reactants were first converted to oximes and then to the dimethylamino compounds. Syntheses of p-(omegadimethylamino-ethoxy, -propoxy, -butoxy, and -pentoxy)2-oximinoacetophenones were achieved. That of p(dimethylaminomethoxy)-2-oximinoacetophenone was unsuccessful. (Author), Pub. in Canadian Journal of Chemistry v40 p1547-53 1962 (Copies available only to DDC users).

Nuclear magnetic resonance was to follow the decomposition of aqueous solutions of 2-methyl-delta 2-oxazoline (0.29 M) at constant pH values in the range - 1 to 14. The decomposition is first order with respect to total oxazoline at any specific pH, but deviates from the simple reaction of water with the protonated species above pH 5. At neutral pH values this is shown to be partially due to a second reaction involving 2-methyl-delta 2-oxazoline and O-acetylethanolamine which yields N-2-acetoxyethyl N'2-hydroxyethyl acetamidate. The decrease in rate constant at pH < 2 is accounted for by variation in the water concentration, which is related to the acidity function. A kinetic expression is derived for the decomposition over the whole pH range studied. The decomposition of the amidate is also discussed., Pub. in Canadian Journal of Chemistry v41 p1662-70 1963. (Copies available only to DDC users).