3-Azabicyclo[3.3.1]nonane Derivatives: IV. Synthesis of Amino Acids with 3-Azabicyclo[3.3.1]nonane Fragment

A series of 1.5-dinitro-3-azabicyclo[3.3.1]non-6-enes was prepared by reduction of 1-R-2,4- and 1-R-3,5-dinitrobenzenes with potassium borohydride followed by Mannich reaction with formaldehyde and amino acids. The molecular structure of (6-bromo-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-3-yl)acetic acid was studied by X-ray diffraction analysis. The mechanism of decomposition under electron impact was determined for (7-methoxy-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-3-yl)acetic acid.     

Selective reduction of 6-substituted 1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes

Reduction of 6-substituted 1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes gives either saturated 1,5-diamino-3-azabicyclo[3.3.1]nonane or unsaturated 1,5-diamino-3-azabicyclo[3.3.1]non-6-enes, depending on the conditions and nature of substituent in the substrate.     

Reactions of 3-substituted 3-azabicyclo[3.3.1]nonan-9-ones with nitrogen-containing nucleophiles

Condensation of 3-substituted 3-azabicyclo[3.3.1]nonan-9-ones with hydroxylamine and hydrazine hydrate gave the corresponding oximes, hydrazones, and azines. Reductive amination of the title compounds in the presence of sodium triacetoxyhydridoborate led to the formation of 3-substituted 3-azabicyclo[3.3.1]nonan-9-amines which were converted into the corresponding dihydrochlorides by treatment with dry hydrogen chloride. Treatment of 3-tert-butoxycarbonyl derivatives with HCl under analogous conditions was accompanied by elimination of the tert-butoxycarbonyl group to produce 3-azabicyclo[3.3.1]nonan-9-amine dihydrochlorides.     

VI. Synthesis of Heterocyclic Analogs of γ-Aminobutyric Acid from 3,5-Dinitrobenzoic Acid

A series of 7-carboxy-3-R-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes was synthesized by reduction of 3,5-dinitrobenzoic acid with sodium borohydride followed by Mannich reaction with formaldehyde and primary amines. The mechanism of decomposition under electron impact of the 3-azabicyclo[3.3.1]nonane was established. Enthalpies of formation of compounds synthesized were calculated by semiempirical PM3 method.     

Synthèse facile de dérivés du diphényl-2,4-aza-3-bicyclo[3.3.1]nonane et du diphényl-7,8-aza-8-bicyclo[4.3.1]décane

Facile synthesis of derivatives of 2,4-diphenyl-3-azabicyclo[3.3.1]nonane and 7,9-diphenyl-8-azabicyclo[4.3.1]decane The facile synthesis of hydantoins, cyanhydrins and aminonitriles derived from 2,4-diphenyl-3-azabicyclo[3.3.1]nonanone and 7,9-diphenyl-8-azabicyclo[4.3.1]decanone is described. Configurations at C(9) or C(10) of the new compounds wth pharmaceutical and synthetical utility is deduced from their spectral properties.     

Conformational and configurational studies on 3-azabicyclo[3.3.1]nonane (3-abn) derivatives and related systems employing carbon-13 NMR spectroscopy

The ¹³C nmr spectra of 4 cis-2,4-diphenyl-3-azabicyclo[3.3.1]nonanes, 11 cis-2,4-diaryl-3-azabicyclo[3.3.1]-nonan-9-ones, 26 cis-2,4-diaryl-3-azabicyclo[3.3.1]-nonan-9-ols or acetates thereof, 5 cis-2,4-diaryl-3-azabi-cyclo[4.3.1]decan-10-ones or -10-ols and 5 cis-2,4-diphenyl-3-aza-7-thiabicyclo[3.3.1]nonan-9-ones, -9-ols or 9-yl acetates have been recorded. Except for the 7-thia compounds, which appear to exist mainly in the configuration and conformation with the nitrogen-containing ring in the boat form, these compounds seem to exist overwhelmingly in chair-chair conformations. The configuration of the 9-ols and their acetates (syn or anti to the nitrogen-containing ring) has been deduced from the spectra. In a number of cases, the structures assigned differ from those earlier postulated. Broadening of one set of aryl signals (probably those due to the ortho carbons) in the case of N-methyl (but not N-H) compounds without ortho substituents is ascribed to restricted phenyl rotation.     

Synthesis and structure of 7-alkoxyalkyl-3-thia-7-zabicyclo[3.3.1]nonan-9-ones and several of their derivatives

New 7-alkoxyalkyl-3-thia-7-azabicyclo[3.3.1]nonan-9-ones were synthesized by the double Mannich cyclization of tetrahydrothiopyran-4-one with suitable alkoxyalkylamines and paraformaldehyde in acetous methanol. Wolff-Kishner decarbonylation of these bicyclic ketones gave 7-alkoxyalkyl-3-thia-7-azabicyclo[3.3.1]nonanes. The reduction of 7-alkoxyalkyl-3-thia-7-azabicyclo[3.3.1]nonan-9-ones by alkali metal hydride complexes leads to a mixture of two stereoisomeric secondary alcohols, which are epimers at C₍₉₎. Active analgesic, antiarrhythmic, and antibacterial compounds were found among these products. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 585–592, April, 2006.     

Synthesis and properties of 3-substituted 3-azabicyclo-[3.3.1]nonan-9-amines

Catalytic hydrogenation of 3-benzyl- and 3-tert-butoxycarbonyl-3-azabicyclo[3.3.1]nonan-9-one oximes over Raney nickel gave the corresponding 3-substituted 3-azabicyclo[3.3.1]nonan-9-amines which were converted into amides via reactions with acetyl and chloroacetyl chlorides and maleic and succinic anhydrides, into Schiff bases by condensation with benzaldehyde and 4-chlorobenzaldehyde, and into isothiocyanates by treatment with thiophosgene in the presence of K₂CO₃. 3-Benzyl- and 3-tert-butoxycarbonyl-3-azabicyclo-[3.3.1]nonan-9-yl isothiocyanates readily reacted with methanol, aniline, and sodium azide to produce methyl thiocarbamate, thiourea, and dihydrotetrazole-5-thione derivatives having a 3-azabicyclo[3.3.1]nonane fragment.     

Chlorination features of 1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes

The electrophilic chlorine addition to 3-substituted 1,5-dinitro-3-azabicyclo[3.3.1]-non-6-enes in the tetrachloromethane is accompanied at an intramolecular 3,7-cyclization giving 6-chloro-3-R-1,5-dinitro-3-azoniatricyclo[3.3.1.03,7]nonane chlorides. The reaction of the tricyclic quaternary ammonium salts with sodium methoxide leads to the formation of dealkylated and dehydrohalogenated products, 3-substituted 8-chloro-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes, bicyclic products with a halogen atom in an allyl position with respect to the double bond.     

Cu(i)-catalyzed atom transfer radical cyclization of trichloroacetamides tethered to electron-deficient, -neutral, and -rich alkenes: synthesis of polyfunctionalized 2-azabicyclo[3.3.1]nonanes

A novel synthetic entry to 2-azabicyclo[3.3.1]nonanes based on a copper(i)-catalyzed intramolecular coupling of amino-tethered trichloroacetamides and unsaturated nitriles, esters and alkenes, as well as enol acetates, is described. A study of the reaction conditions and the scope of the process is reported.     

Spectroscopic study of 3-methyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-α(β)-ols

3-Methyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-α(β)-ols have been synthesized and studied by ir, ¹H and ¹³C nmr spectroscopy. In deuteriochloroform and perdeuteriobenzene solutions, these compounds adopt a flattened chair-chair conformation in which the cyclohexane ring is more flattened. From the ¹H and ¹³C nmr data, several stereoelectronic effects have been deduced. The complete and unambiguous assignment of all protons of the 3-azabicyclo[3.3.1]nonane system, not described up to date, has been carried out.     

3-Azabicyclo[3.3.1]nonane Derivatives: VIII. Synthesis and Properties of 6(7)-R-3,3-Dimethyl-1,5- dinitro-3-azoniabicyclo[3.3.1]non-6-ene Iodides

N-Alkylation of 6(7)-R-1,5-dinitro-3-methyl-3-azabicyclo[3.3.1]non-6-enes with methyl iodide afforded a series of quaternary ammonium salts whose yield depended on the solvent polarity and character of substituents located in positions 6 or 7 of substrate. The presence of electron-withdrawing groups reduced the yield of the target products compared to unsubstituted compound, whereas the electron-donor substituents increased the yield. As shown by the X-ray diffractionstudy the congormation of the substances was not changed in the course of quaternization. The DTA-TG analysis revealed that in the first stage of thermolysis the 6(7)-R-3,3-dimethyl-1,5-dinitro-3-azoniabicyclo[3.3.1]non-6-ene iodides suffer dealkylation. Two fragmentation paths of compounds synthesized under electron impact were observed: elimination either of methyl iodide or aziridinium cation.     

Nitrogen is a requirement for the photochemical induced 3-azabicyclo[3.3.1]nonane skeletal rearrangement!

Specific 3-azabicyclo[3.3.1]nonane derivatives undergo skeletal cleavage when subjected to light or Lewis acidic conditions affording novel heterotricycles, which is in stark contrast to 3-oxabicyclo[3.3.1]nonanes.     

Dirhodium(II)‐Catalyzed Annulation of Enoldiazoacetamides with α‐Diazoketones: An Efficient and Highly Selective Approach to Fused and Bridged Ring Systems

A dirhodium(II)‐catalyzed annulation reaction between two structurally different diazocarbonyl compounds furnishes the donor–acceptor cyclopropane‐fused benzoxa[3.2.1]octane scaffold with excellent chemo‐, regio‐, and diastereoselectivity under exceptionally mild conditions. The composite transformation occurs by [3+2]‐cycloaddition between donor–acceptor cyclopropenes generated from enoldiazoacetamides and carbonyl ylides formed from intramolecular carbene–carbonyl cyclization in one pot with one catalyst. The annulation products can be readily transformed into benzoxa[3.3.1]nonane and hexahydronaphthofuran derivatives with exact stereocontrol. This method allows the efficient construction of three fused and bridged ring systems, all of which are important skeletons of numerous biologically active natural products.     

Synthesis of enantiopure 2-azabicyclo[3.3.1]nonanes by a radical ring closure

The first synthesis of enantiomerically pure 2-azabicyclo[3.3.1]nonanes by an intramolecular radical reaction of the trichloroacetamido group bearing an (S)-N-1-phenylethyl substituent with the silyl enol ether moiety in compounds 7 is described. The procedure allows the two enantiomers of the 2-azabicyclo[3.3.1]nonane-3,6-dione, 3 and ent-3, to be prepared separately. β-Lactam 8 and normorphan 9 are also formed from 7 through an initial radical translocation process in the cyclization step.     

Synthèse de spirohydantoines dérivées du diphényl-2,4-aza-3-bicyclo-[3.3.1]nonane et du diphényl-7,9-aza-8-bicyclo[4.3.1]decane par réaction de Bucherer dans la N,N-diméthylformamide: Influence de la température et cours stéréochimique. Communication préliminaire

Synthesis of Spyrohydantoines Derivatives of 2,4-Diphenyl-3-azabicyclo[3.3.1]nonane and 7,9-Diphenyl-8-azabicyclo[4.3.1]decane via Bucherer Reaction in N,N-Dimethylformamide: Influence of the Temperature and Stereochemical Path The unreactives ketones related to 2,4-diphenyl-3-azabicyclo [3.3.1]nonan-9-one to the Bucherer reaction in usuals conditions show excellent reactivity in DMF. as unique solvant. The stereochemical paths of these reactions and the synthetic utility of the temperature modification are described.     

Reactions of N-substituted 3-azabicyclo[3.3.1]nonan-9-ones with N,N-, N,S-, and N,O-binucleophiles

Condensation of N-substituted 3-azabicyclo[3.3.1]nonan-9-ones with difunctional N,N-, N,S-, and N,O-centered nucleophiles (o-phenylenediamine, 1,2-diphenylethane-1,2-diamine, 2-aminobenzenethiol, cysteine, 2-aminophenol, serine) gave the corresponding spiro heterocyclic compounds fused at the C⁹ atom. Treatment of N-tert-butoxycarbonyl-substituted spiro compounds with anhydrous hydrogen chloride resulted in elimination of the tert-butoxycarbonyl group with formation of spiro[3-azabicyclo[3.3.1]nonane-9,2′-azole] hydrochlorides.     

Ene Reductase Enabled Intramolecular β-C−H Functionalization of Substituted Cyclohexanones for Efficient Synthesis of Bridged Bicyclic Nitrogen Scaffolds

Herein we report that ene reductases (EREDs) can facilitate an unprecedented intramolecular β-C−H functionalization reaction for the synthesis of bridged bicyclic nitrogen heterocycles containing the 6-azabicyclo[3.2.1]octane scaffold. To streamline the synthesis of these privileged motifs, we developed a gram-scale one-pot chemoenzymatic cascade by combining iridium photocatalysis with EREDs, using readily available N-phenylglycines and cyclohexenones that can be obtained from biomass. Further derivatization using enzymatic or chemical methods can convert 6-azabicyclo[3.2.1]octan-3-one into 6-azabicyclo[3.2.1]octan-3α-ols, which can be potentially utilized for the synthesis of azaprophen and its analogues for drug discovery. Mechanistic studies revealed the reaction requires oxygen, presumably to produce oxidized flavin, which can selectively dehydrogenate the 3-substituted cyclohexanone derivatives to form the α,β-unsaturated ketone, which subsequently undergoes spontaneous intramolecular aza-Michael addition under basic conditions.     

3-Azabicyclo[3.3.1]nonane Derivatives: V. Synthesis of 7-Polyfluoroalkoxy-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes

A number of 7-polyfluoroalkoxy-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes were synthesized by reduction of 3,5-dinitrophenyl polyfluoroalkyl ethers with sodium tetrahydridoborate, followed by the Mannich reaction with formaldehyde and primary amines.     

3-Azabicyclo[3.3.1]nonane Derivatives: IX. Synthesis and Molecular Structure of 3-Azabicyclo[3.3.1]nonane-1,5-diamines in Solution and in Solid State

During catalytic reduction with hydrogen on nickel of a series of 3-substituted 1,5-dinitro-3-azabicyclo-[3.3.1]non-6-enes alongside nitro groups reduction occurred also hydrogenation of the double bond. New diamines of the 3-azabicyclo[3.3.1]nonane series were synthesized, and their structure was established by means of IR, ¹H and ¹³C NMR spectroscopy and X-ray diffraction study.