Nitroso Group Transfer from SubstitutedN-Methyl-N-nitrosobenzenesulfonamides to Amines. Intrinsic and Apparent Reactivity

Abstract

We have studied the nitroso group transfer from substituted N-methyl-N-nitrosobenzenesulfonamides to primary and secondary amines, observing that the rate of the reaction increases as a consequence of the presence of electron withdrawing groups on the aromatic ring of the nitrosating agents. The rate constants determined for the nitroso group transfer, ktr, give good Bronsted-type relationships between log ktr (rate constant for nitroso group transfer) and pKaR2NH2+ and pKaleaving group. The study of the nitrosation processes of secondary amines catalyzed by ONSCN and denitrosation catalyzed by SCN-, in combination with the formation equilibrium of ONSCN, has enabled us to calculate the value of the equilibrium constant for the loss of the NO+ group from a protonated N-nitrosamine (pKNOR2N+HNO), which can be defined by analogy with pKaR2NH2+. The value of pKNOX-NO for the loss of the NO+ group from an N-methyl-N-nitrosobenzenesulfonamide was obtained in a similar way. By using values of delta pKNO = pKNOR2N+HNO - pKNOX-NO, we were able to calculate the equilibrium constant for the nitroso group transfer and characterize the transition state. On the basis of Bronsted-type correlations, we have obtained values of beta nuclnorm and alpha lgnorm approximately equal to 0.55, showing a perfectly balanced transition state. In terms of the Marcus theory, the calculation of the intrinsic barriers for the nitroso group transfer reaction shows that the presence of electron withdrawing groups on the aromatic ring of the N-methyl-N-nitrosobenzenesulfonamides does not cause these barriers to vary.

Nitrite Ionic Liquids (IL‐ONO and [bmim]NO2) as Effective Nitrosonium Sources for the Synthesis of α‐Oximinoketones under Mild Heterogeneous Conditions

“…Nitrosation chemistry is very attractive for organic and biological chemists [9][10][11] and many works have been reported about the synthetic and mechanistic aspects of nitrosation or transnitrosation. [12,13] Nitrous acid is the most general reagent which is used for nitrosation and is generated from sodium nitrite and a mineral acid. [14,15] Alkyl nitrites, [16,17] nitrosyl salts, [18,19] Fremy's salt, [20] bis(triphenylphosphine)nitrogen (1＋) nitrite, [21] alkyl thionitrite and thionitrate, [22] polymer-supported nitrosation reagent, [23] nitrosonium ethyl sulfate, [24] and [NO ＋ •Crown• 3 2 H(NO ) -] [25] have been used as nitrosating agents.…”

Use of polymeric nitrosation reagents for the N‐nitrosation of secondary amines under mild and heterogeneous conditions

“…4 N-nitrosation of amines is an important reaction in organic synthesis. N-nitrosoamines have drawn considerable interest in recent years mainly due to their strong mutagenic and carcinogenic properties, 5 it has also been found that these compounds have vasorelaxant activity have been used as pesticides.…”

Nitrosation of Amines in Non‐Aqueous Solvents − Difference Between N−N=O and O−N=O Nitroso Donors

“…[8] Nitroso group transfer can also take place with an N-nitroso donor, NϪNϭO, as in the case of the N-nitrososulfonamides. [9] In an aqueous medium the mechanism of nitroso group transfer from alkyl nitrites [10] or N-nitrososulfonamides [11] to amines takes places in a concerted manner (Scheme 3). The nitroso group transfer occurs in the slow step and the protonation of X Ϫ and deprotonation of N-nitrosamine occur subsequently.…”