A. A. Fomichev

Synthesis and transformations of 1-methyl-4-azafluorene

By means of catalytic dehydrocyclization of dimethyl-substituted 2-phenylpyridines in a pyridine ring to 1(2,3)methyl-4-azafluorenes with subsequent oxidation, synthesis of alkaloid onychine — 1-methyl-4-azafluorene — several of its isomers were achieved. Using 1-methyl-4-azafluorene, we obtained a C9 furfurylidene product, substituted tetrahydroindine[1,2-b]pyridine and NH-indine[1,2-b]-pyridine. We obtained 7-nitro-1-methyl-4azafluorene by nitration of onychine and oxidation of nitro-substituted azafluorene; this indicates an identical orientation of 4-azafluoren(one) and fluoren(one) during nitration.

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.

New method for the synthesis of pyrido[1,2-a]benzimidazole

A catalytic method for the conversion of α-(phenylamino)pyridines to pyrido-[1,2-a]benzimidazoles was developed.

1-Methyl(benzyl)-2,5-dimethyl-4-N-[aryl(alkyl)amino]piperidines and their acyl derivatives

N-Substituted γ-aminopiperidines and their benz- and propioamides have been synthesized from γ-piperidones. The stereoisomeric amines and amides have been separated and identified.

9-IMINO(AMINO)-10-SILA-2-AZAANTHRACENES

Abstract9-Imino derivatives of dihydrosilaazaanthracenes were obtained from 10,10-diorganosila-2-azaanthrones. It was shown by PMR spectroscopy that they exist in the form of Z and E isomers. The azomethines were reduced to secondary amines, from which the N-acyl derivatives were obtained.

NMR spectral parameters of 1-chloroaziridine

l-Chloroaziridine is a classical case of hindered nitrogen inversion. Doubt has been cast on the PMR data obtained for this compound (3Jtran s = 2.54, 2j = -1.72 Hz) [i] since these coupling constants are significantly less than for l-chloro-2-methylaziridine [2] and other aziridines [3]. We obtained the following parameters by analyzing the PMR spectra at 400 MHz in CDCI 3 using the PANIC iteration program. These parameters differ significantly from those obtained by Pauelsen and Greve [i].

INVESTIGATION OF THE STEREOCHEMISTRY OF N-SUBSTITUTED 2,5-DIMETHYL-4-PIPERIDINONES BY NMR-SPECTROSCOPY

The conformations of the cis and trans isomers of N-substituted 2,5-dimethyl-4-piperidinones were studied by means of the1H and13C NMR parameters. It was established that in the case of bulky and electron-acceptor substituents attached to the N atom the cis isomers are virtually completely represented by the chair (2a,5e) conformation, while the trans isomers are characterized by the chair (2e,5e) ⇄ twistboat (2a,5e) ⇄ chair (2a,5a) conformational equilibrium. It is demonstrated that 1-tert-butyltrans-2,5-dimethyl-4-piperidinone hydrochloride has the twist (2a,5e) conformation.

9-Diazo-10,10-dimethyl-9,10-dihydro-10-sila-2-azaanthracene and 10,10-dimethyl-4′-oxospiro[9,10-dihydro-10-sila-2-azaanthracene-9,2′-azetidine]

The synthesis of the first representative of diazo compounds in the dihydrosilaazaanthracene series and a spiro compound with dihydrosilaazaanthracene and azetidine fragments was realized.

Reaction of 9-diazo-4-azafluorene with unsaturated compounds and cyclic ketones

Spiro[4-azafluorene-9,1′ cyclopropanes] were obtained by the reaction of 9-diazo-4-azafluorene with various alkenes in the form of a mixture of geometrical isomers differentiated according to the position of the substituents in the cyclopropane ring and also also according to position relative to the pyridine ring. In the reaction of 9-diazo-4-azafluorene with cyclopentanone, di(4-azafluorene-9 nyl) oxide is formed, while from its reaction with cyclohexanone, 2′-oxo-spiro[4-azafluorene-9,1′-cycloheptane] is obtained.

4′-Bromo(and azido)-10,10-dimethylspiro[9,10-dihydro-10-sila-2-azaanthracene-9,2′-tetrahydrofuran]

Dehydrobromination of 10,10-dimethyl-9-(2,3-dibromoprop-1-y1)-9,10-dihydro-10-sila-2-aza-9-anthrol with butyllithium follows two routes to give the Z- and E-isomers of furan ring-brominated spiro(dihydrosilaazaanthracene-9,2′-tetrahydrofuran), and the cis- and trans-isomers of 10,10-dimethyl-9-(3-bromoallyl)-9,10-dihydro-10-sila-2-aza-9-anthrol. Analogous compounds have been obtained bearing an azidogroup in the tetrahydrofuran ring, and a spiran with a dihydrofuran fragment. The pure isomers have been isolated, and their structures established.