Structure and Conformational Analysis of 5,5-Bis(bromomethyl)-2-(4-methoxyphenyl)-1,3-dioxane

The structure of 5,5-bis(bromomethyl)-2-(4-methoxyphenyl)-1,3-dioxane has been studied by ¹H and ¹³C NMR and X-ray diffraction. Molecules of the title compound exist in the chair conformation with equatorial orientation of the methoxyphenyl substituent. The dioxane ring inversion path, free conformational energy, and optimal conformation of the aryl group have been determined by computer simulation in terms of the DFT PBE/3ζ method. The calculation results are consistent with the X-ray diffraction data.     

Structure and Conformational Analysis of 5,5-Bis(bromomethyl)-2-methyl-2-phenyl-1,3-dioxane

Russian Journal of General Chemistry - The structure of 5,5-bis(bromomethyl)-2-methyl-2-phenyl-1,3-dioxane 1 has been studied by means of 1H and 13C NMR spectroscopy as well as X-ray diffraction...     

Synthesis of allylic thiocyanates and novel 1,3-thiazin-4-ones from 2-(bromomethyl)alkenoates and S-nucleophiles in aqueous medium

Allylic thiocyanates and novel heterocycles containing the 1,3-thiazin-4-one core are easily obtained in high yields and mild conditions by nucleophilic displacement of 2-(bromomethyl)alkenoates (derived from Morita-Baylis-Hillman adducts) with sulphur-centred nucleophiles in aqueous acetone at 25 °C. Treatment of allylic bromides with NaSCN gave the corresponding (Z)-2-(thiocyanomethyl)alkenoates, while the reaction with thiourea followed by a basic work-up selectively produced (5Z)-2-amino-5-arylidene-1,3-thiazin-4-ones. The structural assignments were confirmed by X-ray diffraction analysis.     

Structure and Conformational Analysis of 5,5-Bis(bromomethyl)-2-[4-(dimethylamino)phenyl]-1,3-dioxane

Russian Journal of Organic Chemistry - The structure of 5,5-bis(bromomethyl)-2-[4-(dimethylamino)phenyl]-1,3-dioxane, a promising reagent for fine organic synthesis and a potential bactericidal...     

Structure and Conformational Analysis of 5,5-Bis(bromomethyl)-2-phenyl-1,3-dioxane

The structure of 5,5-bis(bromomethyl)-2-phenyl-1,3-dioxane was investigated by the methods of 1Н, ¹³С NMR spectroscopy and X-ray analysis. The molecule exists in the chair conformation with the equatorial phenyl group. The routes of interconversion of the ring, free conformational energy and optimal conformation of the phenyl group were determined using computer modeling by the method of DFT (PBE/3ξ). The results are consistent with the data of X-ray analysis.     

Synthesis of 2-spiro-(1,2-dihydroperimid-2-yl)-5,5-dialkyl-2,3,5,6-tetrahydropyrrolo[2,1-a]-isoquinolin-3-ones

2,3-Dioxpyrrolo[2,1-a]isoquinolines react with 1,8-naphthalenediamine in 2-propanol in the presence of p-toluenesulfonic acid to give 2-spiro-(1,2-dihydroperimid-2-yl)-5,5-dialkyl-2,3,5,6-tetrahydro-pyrrolo[2,1-a]isoquinolin-3-ones whose structure was confirmed by X-ray analysis. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1849–1854, December, 2008.     

Synthesis of 1,3-dialkyl-5-(hetaryl-1-yl)-1,3-dihydrobenzimidazol-2-ones

Reactions of 5-amino-1,3-dialkyl-1,3-dihydrobenzimidazol-2-ones with 2,5-dimethoxytetrahydrofuran and 2,6-dimethyl-γ-pyranone led to the formation of 1,3-dialkyl-1,3-dihydro-5-(pyrrol-1-andл)benzimidazol-2-ones and 1-(1,3-dialkyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)-2,6-dimethylpyridin-4-ones.     

A new approach towards 2-amino-1-aryloxy-3-methoxypropanes from 1-arylmethyl-2-(bromomethyl)aziridines

1-Arylmethyl-2-(bromomethyl)azirdines were converted into the corresponding 2-(aryloxymethyl)aziridines upon treatment with the appropriate potassium phenoxides in DMF/acetone in excellent yields, followed by regioselective ring opening towards N,N-di(arylmethyl)-N-(2-bromo-3-aryloxypropyl)amines using benzyl bromide in acetonitrile. Treatment of the latter β-bromoamines with sodium methoxide afforded the desired 2-amino-1-aryloxy-3-methoxypropanes as the major compounds (49-58%) besides the isomeric 3-amino-1-aryloxy-2-methoxypropanes in minor quantities (9-15%).     

Synthesis of isoquinoline derivatives of quinoxalin-2-one from pyrrolo[2,1-a]isoquinoline-2,3-diones and o-phenylenediamine

Reactions of 5,5-dialkyl-2,3,4,5-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-diones with o-phenylenediamine in the presence of a catalytic amount of hydrogen chloride or p-toluenesulfonic acid involved opening of the pyrrole ring with formation of 3-(3,3-dialkyl-1,2,3,4-tetrahydroisoquinolin-1-ylidenemethyl)quinoxalin-2(1H)-ones. The presence of an enamine fragment in the products was confirmed by reaction with oxalyl chloride.     

Novel synthesis of 2-aminopentanedinitriles from 2-(bromomethyl)aziridines and their transformation into 2-imino-5-methoxypyrrolidines and 5-methoxypyrrolidin-2-ones

1-Arylmethyl-2-(bromomethyl)aziridines were transformed into 2-[N-(arylmethyl)amino]pentanedinitriles upon treatment with an excess of potassium cyanide in DMSO through an unprecedented and peculiar reaction mechanism, involving base-induced ring opening of intermediate 2-(cyanomethyl)aziridines into allylamines, followed by migration of the double bond out of the conjugation towards aldimines via enamine intermediates. The resulting aminopentanedinitriles served as substrates for the synthesis of novel 2-imino-5-methoxypyrrolidines upon treatment with sodium methoxide in methanol, which were either acetylated at the free imino group to afford the more stable N-acetylimino derivatives or hydrolyzed towards the corresponding synthetically relevant 5-methoxypyrrolidin-2-ones.     

Structure and Conformational Analysis of 5,5-Bis(bromomethyl)-2,2-diphenyl-1,3-dioxane

Russian Journal of Organic Chemistry - The structure of 5,5-bis(bromomethyl)-2,2-diphenyl-1,3-dioxane was studied by 1H and 13C NMR spectroscopy and X-ray analysis. Its molecules in crystal adopt a...     

Tri-component reaction of 2-alkyl-4,5-dichloropyridazin-3(2H)-ones: synthesis of 5-cyano-5-(pyrimidin-2-yl)-2,7-dialkyl-5H-dipyridazino-[4,5-b:4,5-e]-4H-thiopyran-1,6-dione and 2-(4-cyanophenoxy) pyrimidine

Reaction of 2-alkyl-4,5-dichloropyridazin-3(2H)-ones with p-cyanophenol and 2-mercaptopyrimidine in the presence of base gave 2,4,5-trisubstituted-pyridazin-3(2H)-ones 4-9, 2-(4-cyanophenoxy)pyrimidine (10) and 5-cyano-5-(pyrimidin-2-yl)-2,7-dialkyl-5H-dipyridazino[4,5-b:4,5-e]-4H-thiopyran-1,6-diones 11 as a novel heterocycle.     

Novel diastereoselective synthesis of bicyclic beta-lactams through radical cyclization and their reduction toward 2-(1-alkoxy-2-hydroxyethyl)piperidines and 2-(1-alkoxy-2-hydroxyethyl)azepanes

1-Allyl- and 1-(3-phenylallyl)-substituted 4-(2-bromo-1,1-dimethylethyl)azetidin-2-ones were transformed into 3-substituted 7-alkoxy-5,5-dimethyl-1-azabicyclo[4.2.0]octane-8-ones through radical cyclization by means of n-tributyltin hydride and AIBN in toluene with excellent diastereocontrol (>or=99%). The radical cyclization of 4-(2-bromo-1,1-dimethylethyl)-1-(2-methylallyl)azetidin-2-ones afforded 8-alkoxy-3,6,6-trimethyl-1-azabicyclo[5.2.0]nonan-9-ones in good diastereomeric excess (75-78%). The reductive ring opening of 1-azabicyclo[4.2.0]octane-8-ones and 1-azabicyclo[5.2.0]nonan-9-ones with lithium aluminum hydride resulted in novel 2-(1-alkoxy-2-hydroxyethyl)piperidines and -azepanes, which were isolated as single isomers.     

Ring opening reactions of 1-arenesulfonyl-2-(bromomethyl)aziridines

The reactivity of 1-arenesulfonyl-2-(bromomethyl)aziridines with respect to lithium dialkylcyanocuprates and lithium dialkylcuprates (Gilman reagents) has been evaluated for the first time, pointing to the conclusion that these substrates can be applied successfully as synthetic equivalents for the 2-aminopropane dication synthon towards 2-alkylaziridines and α-branched N-tosylamides in good yields.     

Synthesis of alkyl 2-(bromomethyl)aziridine-2-carboxylates and alkyl 3-bromoazetidine-3-carboxylates as amino acid building blocks

A short synthesis of alkyl 2-(bromomethyl)aziridine-2-carboxylates and alkyl 3-bromoazetidine-3-carboxylates was developed involving amination, bromination, and base-induced cyclization of alkyl 2-(bromomethyl)acrylates. These new small ring azaheterocyclic α- and β-amino acid derivatives are promising synthons as demonstrated by their transformation to 2-(aminomethyl)aziridine-2-carboxylates and 3-aminoazetidine-3-carboxylates.     

Synthesis and structure of 1,3-dialkyl-4-(sulfonylimino)imidazolidin-2-ones

The reactions of 1,3-dialkyl-4,5-dihydroxyimidazolidin-2-ones with alkyl sulfamides have been studied and previously undescribed 1,3-dialkyl-4-(alkylaminosulfonylimino)imidazolidin-2-ones have been obtained. The structure of 1,3-dimethyl-4-(benzenesulfonylimino)imidazolidin-2-one was investigated by X-ray structural analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1159–1166, August, 2007.     

Highly substituted cyclohexanes: strong proximity effects influence synthetic access to 1,3,5-tris(bromomethyl)-1,3,5-trialkylcyclohexanes (alkyl = methyl, n-propyl)

1,3,5-Tris(bromomethyl)-1,3,5-trialkylcyclohexanes (alkyl = methyl, n-propyl) were prepared. These are the first examples of 1,3,5-tris(halomethyl)-1,3,5-trialkylcyclohexanes. One synthetic method directly converted the corresponding triols with PPh₃Br₂, where an excess of the bromination reagent and high temperature (175 °C) were required. Stoichiometric use of PPh₃Br₂ under mild conditions, successfully employed for the synthesis of the parent tris(bromomethyl)cyclohexane, did not lead to the desired tribromides but rather to cyclic ethers. Proximity effects triggered by the 1,3,5-alkyl groups strongly influence the reactivity of such highly substituted cyclohexanes. An alternative synthetic access to the tris(bromomethyl) compounds was also developed, using 1,3,5-tris(triflatomethyl)-1,3,5-trialkylcyclohexanes (triflato = F₃CSO₃) as synthetic intermediates. An X-ray crystal structure of 1,3,5-tris(bromomethyl)-1,3,5-trimethylcyclohexane was obtained.     

Single step synthesis of 2,3-dialkyl-6-nitro-quinazolin-4(3H)-imines and 3,5-dialkyl-9-nitro-imidazo[1,2-c]quinazolin-2(3H)-ones

A single step synthesis of 2,3-dialkyl-6-nitro-quinazolin-4(3H)-imines and 3,5-dialkyl-9-nitro-imidazo-[1,2-c]-quinazolin-2(3H)-ones from simple carbonyl compounds, primary amines or amino acid methyl esters and 2-azido-5-nitro-benzonitrile was developed. Key intermediates were N,N′-disubstituted amidines obtained by rearrangement of 4,5-dihydrotriazoles; the new heterocyclic rings were formed by spontaneous intramolecular reaction of the amino and cyano groups which are present in the intermediates.     

Chemistry of iminofurans: XI. Synthesis,structure, and cyclization of 4-substituted 2-(aroylhydrazinylidene)-4-oxobutanoic acids

Aromatic hydrazides reacted with 4-aryl-2-hydroxy-4-oxobut-2-enoic and 2-hydroxy-5,5-dimethyl- 4-oxohex-2-enoic acids to give 4-aryl-2-(2-aroylhydrazinylidene)-4-oxobutanoic and 5,5-dimethyl-2-(aroylhydrazinylidene)- 4-oxohexanoic acids. The products were found to exist in solution as mixtures of Z/E-hydrazinylidene and cyclic dihydropyrazole tautomers, and they underwent intramolecular cyclization to 5-aryland 5-tert-butyl-3-(aroylhydrazinylidene)furan-2(3H)-ones by the action of acetic anhydride.     

Selective monoalkylation of phosphorus-substituted CH acids with (bromomethyl)- and 1,4-bis(bromomethyl)benzenes

C-Alkylation of phosphorus-substituted CH acids with various substituted (bromomethyl)arenes under phase transfer catalysis conditions (K₂CO₃/MeCN) proceeds with high selectivity (75—100%) as monoalkylation.