Synthesis of 7H-tetrazolo[1,5-c]pyrrolo[3,2-e]pyrimidines and their reductive ring cleavage to 4-aminopyrrolo[2,3-d]pyrimidines

Some new 7,9-disubstituted 7H-1,2,3,4-tetrazolo[1,5-c]pyrrolo[3,2-e]pyrimidines 5 have been synthesized either by diazotization of 4-hydrazino-5,7-disubstituted-7H-pyrrolo[2,3-d]pyrimidines 4 obtained by hydrazinolysis of 4-chloro-5,7-disubstituted-7H-pyrrolo[2,3-d]pyrimidines 3 or via a substitution reaction between 3 and sodium azide. 5,7-Disubstituted-7H-pyrrolo[2,3-d]pyrimidin-4(3H)-ones 2 were obtained by cyclocondensation of 2-amino-3-cyano-1,4-disubstituted pyrroles 1 with formic acid which on chlorination using phosphorus oxychloride afforded 3 . A novel route for the synthesis of 4-amino-5,7-disubstituted-7H-pyrrolo[2,3-d]pyrimidines 6 by the reductive ring cleavage of 5 has been reported.     

Synthesis and molecular structure of a substituted 8-oxa-10-azatricyclo [7.3.1.0]tridecatetraene

10,11-Dimethyl-9-(coumarin-3 -yl)-12-ethoxycarbonyl-8-oxa-10-azatricyclo[7,3,1.0^2.7]trideca-2,4,6-11-tetraene was isolated from the mixture of products from the condensation of salicyl aldehyde with acetoacetic ester and methylamine. Its molecular structure has been established by x-ray crystallography.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 259–264, February, 1996.     

Synthesis and Structure of 8-Methyl-2-methylene-1,4,6,9-tetraoxaspiro[4.4]nonane

By reacting propylene carbonate with epichlorohydrin 8-methyl-2-chloromethyl-1,4,6,9-tetra- oxaspiro[4.4]nonane was obtained that afforded 8-methyl-2-methylene-1,4,6,9-tetraoxaspiro[4.4]nonane on dehydrochlorination. The spirocompounds synthesized are composed of stereoisomers mixtures containing: cis,syn-, cis,anti-, trans,syn-, trans,anti-isomers and cis,syn-, cis,anti-isomers, respectively. These isomers are distinguished by a different orientation of substituents in positions 2 and 8 with respect to two five-membered rings.     

Synthesis of N-ethoxycarbonyl-7-azabicyclo[4.2.1]nonane and N-ethoxycarbonyl-9-azabicyclo[4.2.1]nonane

The synthesis of N-ethoxycarbonyl-7-azabicyclo[4.2.1]nonane and N-ethoxycarbonyl-9-azabicyclo[4.2.1]nonane, starting from bicyclo[5.1.0]octan-2-one, is described. The key step is the cyclopropyl ring fission by pyridinium chloride.     

Synthesis of dispiro[2.1.3.1]nonane and trispiro[2.1.1.37.15.13]-dodecane

Russian Journal of Organic Chemistry -     

Synthesis of novel piperazine based building blocks: 3,7,9-triazabicyclo[3.3.1]nonane, 3,6,8-triazabicyclo[3.2.2]nonane, 3-oxa-7,9-diazabicyclo[3.3.1]nonane and 3-oxa-6,8-diazabicyclo[3.2.2]nonane

The preparation of four novel bridged piperazine building blocks is described: 3,7,9-triazabicyclo[3.3.1]nonane 1, 3-oxa-7,9-diazabicyclo[3.3.1]nonane 2, 3,6,8-triazabicyclo[3.2.2]nonane 3 and 3-oxa-6,8-diazabicyclo[3.2.2]nonane 4. The scaffold of 1 was synthesized from N,N′-dibromobenzenesulfonamide and ethyl acrylate. Compound 2 may be prepared from identical starting materials or alternatively from α,α′-diglycerol. Compounds 3 and 4 were identified as side products from possible aziridinium intermediates.     

Synthesis of 6-phenyl-3-azabicyclo[4.2.1]nonane

The synthesis of the title compound was achieved in five steps in 19% overall yield. The key step was an intramolecular Mannich reaction.     

Synthesis of 4-azatricyclo[4.3.1.13,8] undecane (4-azahomoadamantane)

Efficient routes for the synthesis of 4-azahomoadamantane (V) via the Beckmann and Schmidt rearrangements are described. The lactam III is unusual in that it forms a stable crystalline hydrochloride IV.     

Synthesis and structure of new 3,7-diazabicyclo[3.3.1]nonane derivatives

Aminomethylation of triethylammonium 4-aryl-3,5-dicyano-6-oxo-1,4,5,6-tetrahydropyridin-2-olates and their sulfur and selenium analogs, as well as the structure of formed products, were studied in details. The reaction is of general character and leads to the formation of 7-substituted 9-aryl-2,4-dioxo-, 9-aryl-4-oxo-2-thioxo-, 9-aryl-4-oxo-2-selenoxo-3,7-diazabicyclo[3.3.1]nonane derivatives or their salts. The structures of ethyl 9-(2-chlorophenyl)-5-cyano-7-(4-methylphenyl)-2-oxo-4-thioxo-3,7-diazabicyclo[3.3.1]nonane-1-carboxylate (as a complex with N-methylmorpholine) and triethylammonium salt of 7-benzyl-4-oxo-2-selenoxo-9-(2-thienyl)-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarbonitrile were studied by X-ray crystallography.     

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.     

Synthesis and Stereochemistry of Some 3-Azabicyclo[3.3.1]nonane Derivatives

Michael reactions of methyl (ethyl) 1-benzyl-4-oxopiperidine-3-carboxylates with a number of ,-unsaturated carbonyl compounds result in formation of 6- and 6,8-substituted methyl (ethyl) 3-benzyl-9-oxo-3-azabicyclo[3.3.1]nonane-1-carboxylates. Stereochemical aspects of these reactions were studied, and some further transformations of the products were performed.     

Enantioselective Synthesis of 3- Azabicyclo[4.3.0]nonane Alkaloids

The stereospecific synthesis of the monoterpene alkaloids (?)-α-skytanthine ((?)- 2 ), (?)-N -demethyle-δ-sky-tanthine((?)- 7 ), and (+)-epidihydrotecomanine (+)- 4 was achieved from a common intermediate 22 , which in turn was obtained from (1R,4S,1′S)-2-(1′-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene (10) ,via a ketene aza-Claisen rearrangement. The piperidine derivative (+)- 31 , formally the aza-analogue of (+)-isoiridomyrmecin, was also obtained from the same intermediate 22 .     

Pyrolysis of 8,8-dimethyl-8-sila-2,3,4,5-tetrathiabicyclo[4.3.0]nonane

Conclusions The main products of the pyrolysis of 8,8-dimethyl-8-sila-2,3,4,5-tetrathiabicycIo-[4.3.0]nonane at 400 are 1,1-dimethylsilacyclopent-3-ene and 1,1-dimethyl-1-sila-2-thiacyclo-hexa-3, 5-diene, and at 600 carbon disulfide and thiophene; silacyclopentene is the sole reaction product, characteristic for the mass-spectrometric decomposition of the initial tetrasulfide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No, 4, pp. 902–905, April, 1986.     

The synthesis of 1,2-diazabicyclo[3,3,1]nonane and 1,9-diazabicyclo-[4,3,0]nonane. iv

The new bicyclic systems 1,2-diazabicyclo[3,3,1]nonane and 1,9- diazabicyclo [4,3,0]nonane have been synthesized from 2- (and 3-) piperidineacetic acid via their nitroso-derivatives, and 3-oxo-1,2 diazabicyclo [3,3,1]nonane and 8-oxo-1,9-diazabicyclo[4,3, 0]nonane.For Part III, see [3].     

Synthesis of 1,10-phenanthrolines fused with bicyclo[3.3.0]octane and bicyclo[3.3.1]nonane frameworks

Reactions of bicyclo[3.3.1]nonane-2,6-dione and bicyclo[3.3.0]octane-3,7-dione with 8-amino-7-quino-linecarbaldehyde under basic conditions led to fused nonplanar compounds with one or two 1,10-phenanthroline moieties. The novel heterocyclic systems bicyclo[3.3.1]nonano[2,3-b]bis[1,10]-phenanthroline, cis-bicyclo[3.3.0]octano[3,2-b:7,6-b']bis[1,10]phenanthroline, bicyclo[3.3.1]nona-no[2,3-b:6,7-b']bis[1,10]phenanthroline, and 8H-9,16-methanoindolo[2',3':5,6]cycloocta[1,2-b]bis-[1,10]-phenanthroline have been synthesized and characterized.     

Synthesis and Some Reactions of New N-[Aryl(Benzyl,Cyclohexyl, Propyl)sulfonyl]-4-azatricyclo[5.2.1.02,6]dec-8-enes

A synthesis was accomplished of 4-azatricyclo[5.2.1.02,6]dec-8-ene by aminolysis of bicyclo[2.2.1]hept-2-ene-endo,endo-5,6-dicarboxylic acid anhydride followed by transformation of amidoacid into imide that was subsequently reduced by lithium aluminum hydride. The reaction of the key tricyclic amine with sulfonyl chlorides afforded N-[aryl(benzyl, cyclohexyl, propyl)sulfonyl]-4-azatricyclo[5.2.1.02,6]dec-8-enes.The sulfonamides were subjected to epoxidation with perphthalic acid. By reaction of sulfonamides with p-nitrophenyl azide triazolines were obtained. The structure of compounds synthesized was confirmed by IR, ^1Hand ¹³ NMR spectra.