Diquaternary salts. I. Preparation and characterization of the diquaternary salts of some diazines and diazoles

Abstract

hydrogen and the -NCX group could be through the orbitals of the C=X bond. However, this formulation leaves unanswered the fact that only HNCO and HNCS are detected in the products, although under the conditions of our analysis, namely, at least 25% decomposition and in a 10-cm ir gas cell, this could be accounted for if the rate constant of isomerization of these species is at least twenty times larger as that for elimination. We plan to do more work along these lines and to extend the investigation to the isoselenocyanates.An indication of the degree of polarity of the reaction is obtained from Table VI where a similar effect of amethylation on rate is observed for isocyanates and isothiocyanates suggesting identity of mechanism. The absolute magnitude of this effect, although com-parable with that found in the acetates, is much less than in the case of alkyl halides, a reaction regarded as quasiheterolytic.19Experimental Section An all-glass apparatus of conventional design was used. The reaction vessel was a cylinder of about 380-ml capacity and fitted with a glass-diaphragm gauge which allowed the kinetics to be followed manometrically. The temperature of the fumance was kept constant within 0.2°b y means of an RT5 Mk.2 temperature controller from Associated Electrical Industries, England.Reagents.-Isopropyl and ieri-butyl isocyanates were laboratory reagents from K & K Laboratories, Inc., that had been (19) A. Maccoll, Chem. Rev,, 69, 32 (1969).

Novel synthon for incorporating 1,3-dimethyl-imidazolium group into molecular architecture

“…Although the methylation of N-1 proceeds smoothly even at low temperature, alkylation of the tertiary N-3 requires prolonged heating at high temperature for several days, 16 apparently due to reduced nucleophilicity of the N-3 atom. 17 In this communication we describe an effective method to prepare imidazoliums by using trimethyloxonium salts, also known as Meerwein salt 18 , which has been used previously to quaternize a variety of heterocyclic amines. 17, 19 We also report solvent dependent tautomerism of the synthesized compounds and their ability to participate in different reactions.…”

Quaternary 4-Amino-1,2,4-triazolium Salts: Crystal Structures of Ionic Liquids and N-Heterocyclic Carbene (NHC) Complexes

“…Interestingly, the reaction of 1-methyl-1,2,4-triazole with Me 3 O + BF 4 − under forceful conditions is known to produce 1,2,4-trimethyl-1,2,4-triazolium dications [33]. Preliminary experiments with Me 3 O + BF 4 − in dichloromethane showed that 4-amino-1,2,4-triazole gave mixtures of at least mono-, di-and trimethylated products of not yet fully known constitution.…”

Thiadiazoles

“…Methylation with iodomethane occurs at N4; when trimethyloxonium tetrafluoroborate is used as methylating agent, the reaction takes place at both nitrogen atoms, leading to the diquaternary salt 390 (Scheme 14.105) [213]. Reaction of 3-amino-1,2,4-thiadiazole (396) with trimethyloxonium tetrafluoroborate occurs at N2 to yield the thiadiazolium salt, which, on basification, undergoes a Dimroth rearrangement to give the 5-methylamino derivative 397 (Scheme 14.108) [215].…”