Bond Scission in Sulfur Compounds. Part X. The Hydrazinolysis of Methyl p-Nitrophenyl Sulfate

Abstract

ERWIN BUNCEL and CLAUDIO CHUAQUI. Can. J. Chem. 53, 1275Chem. 53, (1975. Reaction of methyl p-nitrophenyl sulfate with the hydrazine-hydrazine hydrochloride system in methanol gives rise to different types of behavior depending on the state of ionization of the reagent. For the H2NNH2/H2NNH3+ combination the observed reaction is conversion of methyl p-nitrophenyl sulfate to p-nitrophenyl sulfate ion (alkyl-oxygen scission). For the H2NNH3+/+H3NNH3+ combination, or with +H3NNH3+ alone, one observes the consecutive processes methyl p-nitrophenyl sulfate + p-nitrophenyl sulfate ion + p-nitrophenol (alkyl-oxygen followed by sulfur-oxygen scission). For the alkyl-oxygen scission process, i.e. nucleophilic displacement on the alkyl carbon, the observed pseudo first-order rate constant is given by the contributions of several nucleophilic species; k,,,. A method for the dissection of k,,, into the constituent terms is given. The sulfur-oxygen scission process is an acid catalyzed reaction and the measured kinetic data have been utilized for the derivation of the pK. of +H3NNH3+ in methanol. Rate data for the conversion of sodium p-nitrophenyl sulfate to p-nitrophenol in methanol containing HCI have also been determined in this connection.ERWIN BUNCEL et CLAUDIO CHUAQUI. Can. J. Chem. 53, 1275Chem. 53, (1975. La riaction du p-nitrophinyl sulfate de methyle avec le systime hydrazine -chlorhydrate d'hydrazine dans le mkthanol donne lieu a differents types de reaction dependant de I'Ctat d'ionisation du reactif. Pour la cornbinaison H2NNH2/H2NNH3 +, la reaction observte est la transformation du p-nitrophknyl sulfate de mkthyle en ion p-nitrophenyl sulfate (scission alkyle-oxygene). Pour la combinaison H 2 N N H 3 + / + H 3 N N H 3 + ou avec +H3NNH3+ seul, on observe des rkactions consecutives allant du p-nitrophknyl sulfate de methyle + I'ion p-nitrophknyl sulfate + p-nitrophenol (scission alkyle-oxygene suivie par une scission soufreoxygene). Pour le processus de scission alkyle-oxygene, i.e. le deplacement nuclCophile sur le carbone de la chaine alkyle, la constante de vitesse du pseudo premier ordre qui est observee est obtenue a partir des contributions de plusieurs espkes nucleophiles; k,,, = k,,, + kc,-IC1-1 + ~H~N N~~+ [ H~N N H~+ ] + ~H~N N H~[ H~N N H~] .Ondonne une methode pour ladissection du k,,, en ses termes constituants. Le processus de scission soufre-oxygene est une rkction acido catalyske et on a pu utiliser les valeurs cinetiques mesurkes pour dtterminer les valeurs de pK, du +H3NNH3+ dans le mkthanol. A cet effet on a aussi determine la vitesse de transformation (dans du methanol contenant du HCI) du p-nitrophknyl sulfate de sodium en p-nitrophenol.[Traduit par le journal]Methyl p-nitrophenyl sulfate is the first member of the family of mixed alkyl aryl sulfates to be subjected to intensive investigation. This particular substrate offers several possible electrophilic centers in its reactions with nucleophiles: the alkyl carbon, the sulfonyl sulfur, and the aryl carbon. So far we have reported on ...

Bond scission in sulfur compounds. 13. Reactivity-selectivity correlations. 3. The .alpha. effect at saturated carbon. Reactivity studies of methyl phenyl sulfates with nucleophiles

“…Thus a new class of methyl derivatives which has been available to us are the mixed alkyl aryl sulfates, and we had found, for example, that methyl p-nitrophenyl sulfate reacts with nucleophiles such as methoxide and halide ions solely at the methyl carbon, with ArOS03-as the leaving group. [34][35][36] In addition, reaction of a series of substitued aryl methyl sulfates shows interesting behavior in relation to the re- [Nu] varied over the range 1 X 10"3 to 30 X 10"3 M, de-pending on the reactivity of Nu. Data for Cl" and Na" are from ref activity-selectivity principle (RSP).2 It thus appeared possible that a study of the a effect with these alkyl aryl sulfates could lead to useful information, especially through variation of the substituent in the aryl moiety.…”

The acidolysis of p-nitrophenyl sulfate. A kinetic spectrophotometric method for evaluation of pKa

“…We reported recently on the kinetic study of o methyl p-nitrophenyl sulfate with some nucleo- [I] o ,~ philic reagents in methanol (1)(2)(3). It was found that a reagent HNu causes two reaction stages to rates was given (4) for the case that kA and kB (+SO>) are comparable in magnitude.…”

“…It was found that a reagent HNu causes two reaction stages to rates was given (4) for the case that kA and kB (+SO>) are comparable in magnitude. +H3NNH3+ combination, or with +H3NNH3+ An interesting situation arose when the re-alone in methanol solvent (3). In such systems action was performed with the H2NNH3+/ the methanolysis reaction (HNu = CH30H) Can.…”

Ultraviolet spectrometry

“…Applications of ultraviolet spectrophotometry to kinetic studies continue to be reported in significant numbers. The types of reactions followed include the hydration of pteridine ( 181) and 1-alkynylamines (232), the hydrolysis of tolunitrile (35) and phenyl substituted 2-methoxy-l,3dioxolanes (43), the addition of alcohols to substituted benzylideneanilines (164), the solvolysis of 5-iodocytosine (74), the hydrazinolysis of methyl-p-nitrophenyl sulfate (34), the dehalogenation of halogenated uracils (194), the acylation of ascorbic acid in water (175), the reaction of cyclic anhydrides with anhydrous acetic acid (86), the ozonolysis of acetylenes (147), the aromatization of 4-carboxybenzene oxide (187), the reaction of iodate with iodide (205), the oxidation of sulfite by hydrogen peroxide (97), the complexation of copper(II) with a variety of ligands (190), the ligand substitution reactions of nickel and cobalt ions (42), the formation of zinc salicylaldehyde Schiff Bases (141), and the reduction of americum(VI) by neptunium(V) (248). The rate of electron transfer from sodium anthracenide to cis-stilbene, leading to the isomerization of the latter, was measured (128).…”