SYNTHESIS OF NEW DERIVATIVES OF 3-AZABICYCLO[3.3.1]NONANES BASIS ON N-(2-HYDROXY-3,5-DINITROPHENYL)ACETAMIDE σ-ADDUCT

Abstract

A number of new derivatives of N-(3-R-1,5-dinitro-8-oxo-3-azabicyclo[3.3.1]non-6-en-7-yl)acetamides have been synthesized by Mannich condensation of hydride σ-adduct of the N-(2-hydroxy-3,5-dinitrophenyl)acetamide with formaldehyde and primary amines. The synthesis was carried out with two stages. In the first stage, under the action of sodium tetrahydride borate on a solution of N-(2-hydroxy-3,5-dinitrophenyl)acetamide, the C = C bonds of the aromatic ring were reduced to form a 3-charge hydride adduct. The resulting diaduct was isolated from the solution and, while cooling with ice, was introduced into Mannich-condensation with formaldehyde and a solution of the primary amine or amino acid. When the reaction mixture was acidified with dilute orthophosphoric acid to pH 4–5, precipitates of the target products precipitated. After recrystallization from ethanol, the yield of the target products, depending on the substituent at the nitrogen atom, ranged from 55 to 90%. This method is distinguished by relative simplicity, availability of reagents and allows under mild conditions to transfer from the aromatic system activated by nitro groups to 3-azabicyclo[3.3.1]nonane derivatives, containing promising from the point of view of further functionalization nitro, carbonyl and amino groups. The structure of the compounds obtained was proved by IR, 1H-, 13C-, two-dimensional correlation NMR spectroscopy, as well as elemental analysis data. In the IR spectra of the obtained substances, the characteristic absorption bands of amide I (1629-1633 cm-1) and amide II (1560-1570 cm-1), as well as antisymmetric (1549-1556 cm-1) and symmetric (1370-1377 cm-1) oscillations of nitro groups were observed. In the NMR spectra in the weakest field, the broadened signal of the proton NH is observed (δ 9.51-9.57 ppm), followed by the singlet signal of the proton at the double bond (δ 8.15-8.16 ppm). The protons of the methylene groups of the bicyclic system are diastereotopic. Therefore, their signals are mutually split into broadened doublets located in the region of 2.66–3.46 ppm.