Directed 2-azonia-[3,3]-sigmatropic rearrangements. a convenient preparation of substituted 1-azaspiro[4,5]decanes

3-Acetylpyrrolidines are prepared from 5-methyl-5-vinyloxazolidines in a reaction which involves a directed 2-azonia-[3,3]-sigmatropic rearrangement.     

The preparation of 8-[4-[4-(2-pyrimidinyl)-1-piperaziny]butyl]-8-azaspiro[4,5] decane-7,9-dione hydrochloride

8-[4-[4-(2-Pyrimidinyl)-1-piperaziny]butyl]-8-azaspiro [4,5] decane-7,9-dione hydrochloride (buspirone hydrochloride) was obtained in one pot with a 51.8% overall yield. The key intermediate, 1-(2-pyrimidinyl) piperazine, was synthesized through chlorination and cyclization condensation reaction with diethanolamine as initial material. This modified protocol has the notable advantages of mild reaction condition, convenient operation, and high overall yield.     

Quaternization of 1H-imidazo[4,5-b]pyridine and 4-methyl-4H-imidazo[4,5-b]pyridine

Unsubstituted imidazo[4,5-b]pyridine adds methyl iodide to the pyridine N atom. Treatment of the resulting iodide with base forms 4-methyl-4H-imidazo[4,5-b]pyridine. This nucleophile can readily add methyl iodide to form only one salt, 1,4-dimethylimidazo[4,5-b]pyridinium iodide.L. M. Litvinenko Institute of Physical Organic Chemistry and Coal Chemistry, Ukraine Academy of Sciences, Donetsk 340114. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1232–1233, September, 1994. Original article submitted june 17, 1994.     

Stereoselective synthesis of 2e-phenyl-4e-hydroxy-1-azaspiro[5.5]undecane

6-Phenylspiro(1-aza-7-oxabicyclo[2.2.1]heptane-2-cyclohexane) was synthesized by cyclization of N-benzylidene-1-allyl-1-cyclohexylamine N-oxide, and its reduction splitting yielded 2e-phenyl-4e-hydroxy-1-azaspiro[5.5]undecane.Russian People's Friendship University, Moscow 117198. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 77–80, January, 1998.     

Synthesis of methyl-1,6-dioxaspiro[4,5]decanes using organoselenium mediated cyclization reactions

Three naturally occurring methyl-1,6-dioxaspiro[4.5]decanes have been prepared in good yield using organoselenium mediated reactions during the crucial cyclization process.     

Asymmetric synthesis of 1-azaspiro[4.5]decanes via intramolecular dipolar cycloaddition of nitrones containing the bornane-10,2-sultam chiral auxiliary

The intramolecular 1,3-dipolar cycloaddition of a cyclic nitrone, prepared by an asymmetric electrophilic enolate hydroxyamination using the (2R)-bornane-10,2-sultam chiral auxiliary, proceeds to give bridged and fused cycloadducts with total diastereocontrol. Reduction of the fused isoxazolidine provides a 1-azaspiro[4.5]decane as a potential intermediate in the asymmetric synthesis of the cylindricine alkaloids.     

Synthesis of 1-substituted 2,9,10-trioxatricyclo[4.3.1.0]decanes

A series of 1-alkyl- and 1-alkenyl-2,9,10-trioxatricyclo[4.3.1.0^3,8]decanes, models for the core orthoester structural moiety of resiniferatoxin and synaptolepis factors, was prepared by a transetherification reaction of (±)-all-cis-cyclohexane-1,2,4-triol and trimethyl orthocarboxylates. The synthesis of the starting trimethyl orthocarboxylates is also given in detail.     

Derivatives of benzo[4,5]cyclohepta[1,2-b]thiophene. 4. Synthesis of 1-(9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophen-4-yl)-3-alkylaminoazetidines

Thirteen 1-(9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophen-4-yl)-3-alkylaminoazetidines 11 have been synthesized in three steps from 4-amino-9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophene ( 6 ), which was obtained from the reduction of either 4-azido 4 or 4-hydroxyimino 5 derivatives. All the compounds have been evaluated as potential antidepressive agents.     

Synthesis of 4-methyl-1H-imidazo[4,5-c]quinoline

A four-step synthesis of 4-methyl-1H-imidazo[4,5-c]quinoline from 2-methyl-3-nitro-4-oxo-1,4-dihydroquinoline is developed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 231–232, February, 1989.     

Methylation of 1-oxo-4-hydroxypyridazino[4,5-b]-quinoxaline

The methylation of 1-oxo-4-hydroxypyridazino[4,5-b]quinoxaline (I) with methyl iodide and diazomethane under various conditions was studied. The structures of the disodium and disilver salts of I were established by means of spectrophotometric methods of analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1418–1420, October, 1973.     

Acylation of 1-oxo-4-hydroxypyridazino[4,5-b]quinoxaline

Monoacyl and diacyl derivatives were obtained, depending on the reaction conditions, by reaction of 1-oxo-4-hydroxypyridazino[4,5-b]quinoxaline with acylating agents. Reductive acetylation leads to compounds with three acetyl groups. The structures of all of the compounds obtained were confirmed by their IR and UV spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 407–410, March 1977.     

Synthesis and Antimycobacterial Activity of New 2-Hydroxy-N-(3-oxo-1-thia-4-azaspiro[4.4]non-4-yl)/(3-oxo-1-thia-4-azaspiro[4.5]dec-4-yl)-2,2-diphenylacetamide Derivatives

Summary. 2-Hydroxy-2,2-diphenylacetohydrazide (2), cyclic ketones, and mercaptoalkanoic acids were converted into 2-hydroxy-N-(3-oxo-1-thia-4-azaspiro[4.4]non/[4.5]dec-4-yl)-2,2-diphenylacetamide derivatives (3, 4) in a one pot procedure. Compounds 3 and 4 were tested for in vitro antimycobacterial activity against M. tuberculosis H37Rv. The compounds were found to provide 0–86% inhibition of mycobacterial growth in the primary screen conducted at 6.25 μg/cm³.     

Derivatives of benzo[4,5]cyclohepta[1,2-b]thiophene. 1. Synthesis and cyclization of N-(9,10-dihydro-4H-benzo[4,5]cyclohepta-[1,2--6]thiophene-4-ylmethyl)amides

Starting from ketone III several acyl derivatives of 4-aminomethyl-9,10-dihydro-4H-benzo[4,5]cyclohepta-[1,2--6]thiophene (VII) have been synthesized. The intramolecular cyclization of some of these new amides through the Bischler-Napieralski reaction is described.     

Some properties of 1-oxo-4-hydroxypyridazino[4,5-b]quinoxaline

The dissociation constants of 1-oxo-4-hydroxypyridazino[4,5-b]quinoxaline were measured by potentiometric titration. It is shown that this compound is a dibasic acid. Its reaction with organic bases, acids, alkalis, and oxidizing agents was studied. Its aminomethylation, hydroxymethylation, and cyanoethylation were also investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 402–406, March, 1977.     

Synthesis of 1,6,7-trioxa-spiro[4.5]decanes

As potential antimalarial agents, four novel spiro-peroxides were designed and synthesized with the peroxy bond introduced employing the Kobayashi’s methodology (with modifications). The results showed that by using cyclic hemiketal as substrates the incorporation of the hydroperoxyl group could be achieved in high yields without recourse to the expensive Sc(OTf)₃ catalyst.