20503-92-8

The condensation reactions of β- and γ-amino alcohols containing phenyl or (η6-arene) tricarbonylchromium substituent with formaldehyde, acetaldehyde, benzaldehyde, and (η6-benzaldehyde)tricarbonylchromium were studied. The resulting 1,3-oxazolidine and 1,3-oxazinane products were isolated in a pure form and identified by different physicochemical methods. The effect of (η6-arene)tricarbonylchromium moiety on the reaction process was demonstrated.

Cumene hydroperoxide (CHP) is widely used in chemical processes, mainly as an initiator for the polymerization of acrylonitrile-butadiene-styrene. It is a typical organic peroxide and an explosive substance. It is susceptible to thermal decomposition and is readily affected by contamination; moreover, it has high thermal sensitivity. The reactor tank, transit storage vessel, and pipeline used for manufacturing and transporting this substance are made of metal. Metal containers used in chemical processes can be damaged through aging, wear, erosion, and corrosion; furthermore, the containers might release metal ions. In a metal pipeline, CHP may cause incompatibility reactions because of catalyzed exothermic reactions. This paper discusses and elucidates the potential thermal hazard of a mixture of CHP and an incompatible material's metal ions. Differential scanning calorimetry (DSC) and thermal activity monitor III (TAM III) were employed to preliminarily explore and narrate the thermal hazard at the constant temperature environment. The substance was diluted and analyzed by using a gas chromatography spectrometer (GC) and gas chromatography/mass spectrometer (GC/MS) to determine the effect of thermal cracking and metal ions of CHP. The thermokinetic parameter values obtained from the experiments are discussed; the results can be used for designing an inherently safer process. As a result, the paper finds that the most hazards are in the reaction of CHP with Fe2+. When the metal release is exothermic in advance, the system temperature increases, even leading to uncontrollable levels, and the process may slip out of control.

N-Phenyl- and N-alkyl-oxazolidines react with alkyl chlorosilanes in the presence of electron rich aromatic compounds with the formation of the expected Mannich bases: 2-methoxycarbonyl-3-methyloxazolidine also reacts with 2-methylfuran in the presence of thionyl chloride to give an a-amino acid derivative: the iminium salt derived from 1,3-dimethylimidazolidine was also shown to react with 2-methylfuran.

Oxazolidines, obtained by the condensation of aldehydes with 2-anilino-1-alkanols, react with the Refortmatsky reagent derived from ethyl bromoacetate under mild reaction conditions to afford ethyl 3-(2-hydroxyalkyl)aminoalkanoates.

Thermolysis of oxazolidines leads to azomethine ylids via cycloreversion.In the liquid phase, these intermediates then give 1-3 dipolar cycloaddition; in the gaseous phase, they lead to aziridines.With an alkyl group in position 2, we observed also the formation of enamines.The effect of substituents on both the cycloreversion reaction and the evolution of azomethine ylids was studied.The mechanism of the process tautomerism aziridine -> azomethine ylid -> enamine is discussed.Keywords - azomethine ylids / oxazolidines / cycloreversion / aziridines / enamines / tautomerism

Formaldehyde reacts with α-amino acids and electron deficient alkenes to produce pyrrolidines.Azomethine ylides involved as intermediates in these reactions have been generated from isolated oxazolidin-5-ones which can be considered as the direct precursors of these ylides.

The reactions of N,N-dimethylaniline derivatives (1) with cumene hydroperoxide in acetonitrile at 100 deg C produce significant amounts of the corresponding N-aryloxazolidine (6).Oxazolidine formation occurs by addition of α-aminomethyl radicals (7) to formaldehyde to give the alkoxy radical (8), followed by intramolecular 1,6 H-atom abstraction, oxidation, and cyclization.The results of labeling experiments and the dependence of the oxazolidine yield on the formaldehyde concentration support this mechanism.Alkoxy radical 8 was generated by an alternative route anddoes give the oxazolidine.Radical addition to the carbonyl carbon of formaldehyde is a reflection of the electron-rich, nucleophilic nature of the α-aminomethyl radical 7 and rapid trapping of the resulting alkoxy radical 8 via intramolecular H-atom abstraction through a six-membered transition state.