Mass spectrometry of organic compounds of group V elements 7—N-alkoxyamines

The suggestion of participation of the participation Ione electron pair of the nitrogen atom in amine-type stabilization has been confirmed by a decrease in amine-type fragmentation and a drastic change in the decomposition routes under electron impact of N-alkoxyamines.     

Atropoenantiomerism of the Z-adduct of 2,3-diethoxycarbonyi-6,6-dimethyl-5,6-dihydro-4-pyridone with dimethyl acetylenedicarboxylate: synthesis and structure in solution and in the crystal

The title adduct (1) was synthesized, and its conformationally and configurationally rigid chiral structure in solution and in the crystal was established by NMR spectroscopy and by X-ray structural analysis. Atropoenantiomers of1 were observed by the¹H NMR method in the presence of a chiral shift reagent. A barrier to their interconversïon was determined, G^x > Z5 kcal mol^–1 (200 °C).Translated fromItvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1796–1799, July, 1996.     

Asymmetric nitrogen

The possibility of tranferring chirality from nitrogen to carbon by a three-step transformation of racemic dimethyl 1-methoxyaziridine-2,2-dicarboxylate into 3-amino-2-chloromethyl-2-methoxyaminopropan-1-ol was demonstrated. The first representative of 1-silyloxyaziridines,viz., dimethyl 1-(tert-butyldimethylsilyloxy)aziridine-2,2-dicarboxylate, was synthesized by acidolysis or thermolysis of triazoline, obtained by the reaction oftert-butyldimethylsilyloxime of dimethy mesoxalate with CH₂N₂     

Mass spectrometry of organic compounds in the group V elements—I: Straight chain aliphatic derivatives

Comparative investigations of the mass spectra of eEH₂, Me₂EH, Et₂EH(E = N, P); Me₃E, Et₃E(E = N, P, As, Sb, Bi). (n-Pr)₃E(E = Sb, Bi); (n-Bu)₃E(E = P, As); (n-C₅H₁₁)₃As and (n-C₆H₁₃)₃As as well as Et₂AsBr have been carried out. Deuteroanalogues, metastable transitions and low voltage spectra were used for elucidation of the fragmentation paths. The mass spectra of MeN(CH₂)₂ and CD₃N(CH₂)₂ were studied to analyse the structure of the fragments. The main degradation path of amines, i.e. α-cleavage, was shown to be untypical for P, As, Sb and Bi derivatives.     

2-Carbamoylaziridine (Leakadine): diastereoselective transformations and stereoelectronic effect*

Diastereoselective transformations of Leakadine were discovered: dimerization during melting or heating in CHCl₃ with the formation of one diastereomer. The obtained dimer reacts with methyl isocyanate under mild conditions with the formation of an N-methylcarbamoyl derivative – also in the form of one diastereomer. In the diastereoselective reaction of Leakadine with dimethyl formamide dimethyl acetal, 2-dimethylamino-1,3-diazabicyclo[3.1.0]hexan-4-one was obtained. The reaction of Leakadine with perfluoroisobutylene was studied.