V. N. Voznesenskii

ASYMMETRIC NITROGEN .57. INVESTIGATION OF THE STEREOCHEMISTRY OF AZIRIDINECARBOXYLIC ACID-DERIVATIVES BY NMR

ConclusionsThe preferred trans configuration of 1,2-disubstituted aziridines and cis configuration of NH-aziridine-2-carboxylic esters were established by means of the1H and13C NMR spectra and the two-dimensional NOESY and COSY-45 spectra.

1H,13C NMR spectral data for α-, β-, and γ-lewisites and identification ofcis, trans, trans-γ-lewisite as a new isomer

The1H and13C NMR spectral parameters of α-, β-, and y-lewisites1–5 were obtained and a new isomer,cis,trans,trans-γ-lewisite5, was isolated and identified on the basis of chemical shifts, relative intensities of the signals, and the intra-chain (3Jhh,3Jch) and interchain (3Jcasch) coupling constants.

Acetyl chloride-3,5-di(tert-butyl)-4-hydroxy-N,N-dimethylbenzylamme salt in the benzylation of organic and inorganic sulfur-containing compounds

The reactions of the quaternary acylammonium salt formed on treatment of3,5-di-tertbutyl-4-hydroxy N,N-dimethylbenzylamine with acetyl chloride, with various organic and inorganic sulfur-containing compounds were studied. The possibility of using this salt for the introduction of a sterically hindered phenol moiety in various sulfur-containing compounds was shown.

Determination of configuration of products of nucleophilic addition to activated acetylenes by the NMR method

ConclusionsIt was shown that the stereospecificity of SSCC3C,Htrans > 3JC,Hcis is applicable as a configurational test for di- and trisubstituted alkenes R2E(Y)C=C(X)H with various heteroatomic substituents (E=N, P, S) and activating groups (X=CO2Alk, CN at Y=H, and X=Y=CO2Alk, CN, CF3).

Structure of products of the reaction of 2-cyanoaziridine with carbonyl compounds

The structure of azimexone (3), the product of the reaction of 2-cyanoaziridine with acetone, was confirmed on the basis of1H and13C NMR spectra. The formation of this product is accounted for by the α-aziridinoalkylating action of an intermediate containing a good leaving iminoyloxy group. Similar reactions were observed for 1-chloromethylaziridine and a 1-aziridinylmethylammonium salt (6), but not for 1-methoxymethylaziridine (7) and 1-aziridinemethanol.

Geminal systems. 50. Solvolysis of 1-tosyloxy-Δ2-1,2,3-triazoline-5,5-dicarboxylate esters and the structure of the solvolysis product, O-tosyl-N-α,α-bis(ethoxycarbonyl)-β-methoxyethylhydroxylamine

Solvolysis of 1-tosyloxy-Δ2-1,2,3-triazoline-5,5-dicarboxylic acid esters (1) occurs via elimination of N2 and leads predominantly to N-β-hydroxylethyl-O-tosylhydroxylamines (II), whose structure was determined unequivocally by x-ray structural analysis. The mechanism of solvolysis of triazolines (I) is discussed, along with the structural characteristics and stabilization factors of the O-tosylhydroxylamine products (II).

Automatic assembly of framework structures

Conclusions1.The automatic assembly of dilactones from α,α′-dihydroxyglutaric acids and their derivatives is controlled not only by configuration (from the d, ℓ and not the meso form) but also by conformation and is not realized in the presence of α,α′-substituents having predominantly pseudoequatorial orientation in the corresponding monolactone. Thus, γ-crotonolactone is formed instead of the expected dilactone during the thermolysis of d,ℓ-α,α′-dihydroxyglutaric acid.2.The diastereomers of α,α′-dibromoglutaric acid and the d,ℓ-forms (in contrast to the meso form) of α,α′-dihydroxyglutaric acid and their esters are conformationally uniform in the case where there is no intramolecular hydrogen bond.3.The meso forms of the conformationally uniform α,α′-disubstituted glutaric acids differ from the d,ℓ-forms in the nonequivalence of the JCH spin-spin coupling constants with the protons of the CH2 group.4.Pseudoaxial preference was detected for the CO2H and CO2Me groups in trans-2-hydroxy-4-carboxy-γ-butyrolactone and its methyl ester respectively.

Asymmetric nitrogen. 68. Geminal systems. 42. Diastereomeric NH-dialkoxyamines with an asymmetric nitrogen atom in an open chain

Conclusions1.For the first time a diastereomerically enriched acyclic NH-dialkoxyamine with asymmetric nitrogen atom in the NH group was obtained.2.By low-temperature PMR spectra the diastereomers of a 1,1-dialkoxyurea with asymmetric amid enitrogen atom were observed.