Transformations of 4,5-Substituted (4S,5S)-2,2-Dimethyl-1,3-dioxolanes

(4S,5S)-4,5-Bis(hydroxymethyl)-2,2-dimethyl-1,3-dioxolane treated with trifluoromethanesulfonyl chloride in pyridine undergoes tandem substitution of one hydroxy group by a triflate group, and the other by pyridinium moiety. In neutral solvents the (4S,5S)-4,5-bis(hydroxymethyl)-2,2-dimethyl-1,3-dioxolane dilithium salt reacts with trifluoromethanesulfonyl chloride affording both triflates and chlorides and also suffers a cleavage of the dioxolane ring followed by transformations of acyclic products. A triflate cationic complex rhodium cyclooctadiene (4S,5S)-2,3-dihydroxy-1,4-bis(dimethylamino)-2,3-O-isopropylidenebutane was prepared and used as catalyst for hydrogenation of -acetamidocinnamic and itaconic acids.     

Synthesis of new imidazo[4,5-d][1,3]diazepine derivatives from 5-amino-4-(cyanoformimidoyl)imidazoles

N¹-[(Z) -2- Amino-1,2-dicyanovinyl]formamidines 1a-d react readily with tosyl isocyanate to form novel 8-amino-3-substituted-5-oxo-7-tosylaminoimidazo[4,5-d][1,3]diazepines 6a-d rather than the 6-cyano-2-oxopurine derivatives 5a-d expected. Compound 5a has been synthesized from 1a by reaction with ethyl chloroformate and base-catalyzed cyclization of the resultant 5-ethoxycarbonylamino-4-(cyanoformimidoyl)imidazole. Treatment of the 5-amino-4-cyanoimidazoles 7a and b with tosyl isocyanate under similar conditions gives the 4-cyano-5-(3′-tosylureido)imidazoles 8a and b , which on treatment with ethanolic ammonia cyclizes to the corresponding isoguanines 10a and b .     

2-[Hydroxy(dialkyl)methyl]-4-aryl-6,6-disubstituted 4,5-dihydro-6H-1,3,4-oxadiazinones-5

The reactions of arylhydrazides of dialkylglycolic acids with chlorides of -halocarboxylic acids, followed by cyclization, yielded 2-[hydroxy(dialkyl)methyl]-4-aryl-6,6-disubstituted 4,5-dihydro-6H,1,3,4-oxadiazinones-5.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 896–897, July, 1984.     

5-Methyl-4H-1,3-dioxins,new chiral building blocks: transformation into (R)- and (S)-4-hydroxymethyl-4-methyl-1,3-dioxolanes via oxidation and rearrangement and determination of the absolute configuration

5-Methyl-4H-1,3-dioxins obtained by asymmetric double-bond isomerization have been transformed into 4-hydroxymethyl-4-methyl-1,3-dioxolanes by m-chloroperbenzoic acid oxidation, ring contraction and reduction. The stereochemical course of this transformation has been studied, while the relative configuration of the intermediate oxidation product and the absolute configuration of the resulting camphanyl ester of 2-tert-butyl-4-hydroxymethyl-4-methyl-1,3-dioxolane was established by X-ray crystallography. From these results, the absolute configuration of the dioxins has been deduced.     

Direct enantioselective approach to oxazolo[4,5-e]isoindoles from [(S)R]-1-aminosubstituted-4-(p-tolylsulfinyl)-1,3-butadienes

The enantioselective construction of [3aS,5aR,8aR,8bR]-1-(p-methoxyphenyl)-3a,7-dimethyl-3a,5a,8b,8a-tetrahydro-1H-oxazolo[4,5-e]isoindole-2,6,8-trione is achieved from enantiopure [(S)R]-(1E,3E)-2-methyl-1-(p-methoxyphenyl)amino-4-(p-tolylsulfinyl)-1,3-butadiene and N-methylmaleimide through a short sequence involving a Diels–Alder reaction, a sulfoxide–sulfenate rearrangement and intramolecular cyclization.     

Totally selective reaction of CO2 with enantiopure amino epoxides under mild reaction conditions. synthesis and synthetic applications of enantiopure (4R,1'S)- or (4S,1'S)-4-(1-Aminoalkyl)-2-oxo-1,3-dioxolanes

The reaction of chiral (2R,1'S)- or (2S,1'S)-2-(1-aminoalkyl)epoxides 1 or 2 with CO2, generated from acidic treatment of an aqueous solution of NaHCO3 at room temperature, efficiently afforded enantiopure cyclic carbonates 3 or 4, respectively, with total selectivity. Compounds 3 and 4 were readily transformed into the corresponding diols 7 and 8 by reaction with LiAlH4 or by basic hydrolysis. When compounds 3 or 4 were allowed to react with methyllithium at -78 degrees C, O1-acetylalkane-1,2-diols 9 and 10 were obtained with total or high selectivity.     

Synthesis and rearrangement of [1,1′-bicyclobutyl]-1-ols and spiro[3.4]octan-5-ols: a general access to bicyclo[3.3.0]octenes (hexahydropentalenes)

Several new Grignard reagents based on substituted cyclobutanes have been generated and added to cyclobutanones to yield mono- to trimethylated [1,1′-bicyclobutyl]-1-ols. Mono- to trimethylated spiro[3.4]octan-5-ols have been prepared from the parent ketone via alkylation and/or addition reactions. Upon treatment with acid, all [1,1′-bicyclobutyl]-1-ols and spiro[3.4]octan-5-ols rearrange to yield a single bicyclo[3.3.0]octene.     

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.     

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 1,3-dialkyl-5-(pyrrol-1-yl)-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-ones

Russian Journal of Organic Chemistry -     

Synthesis of 1-[4-(1,3-diaryl-4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-5-yl)-2,3,5,6-tetrafluorophenyl]piperidin-4-ols and their acrylates

(4-Hydroxypiperidin-1-yl)tetra- and -octafluorochalcones reacted with phenylhydrazine in acetic acid to give mixtures of polyfluoro-1,3,5-triaryl-4,5-dihydro-1H-pyrazoles and their O-acetyl derivatives. Analogous reactions in ethanol afforded in satisfactory yields 1-[4-(1,3-diaryl-4,5-dihydro-1H-pyrazol-5-yl)-2,3,5,6-tetrafluorophenyl]piperidin-4-ols which were treated with acryloyl chloride to obtain the corresponding acrylates that are promising as monomers for the preparation of fluorescent films.     

Novel bent-shaped liquid crystalline compounds II. Synthesis and properties of the 1,3-bis4-[4-(4-alkyloxybenzoyloxy)benzylidene]aminophenoxypropan-2-ols

A series of new symmetric dimer compounds was synthesized, constaining 2-hydroxy-1,3-dioxypropylene as the central linkage and terminal alkyl chains with different lengths. The chemical structures of the liquid crystal dimers (2ES-n) were examined by FTIR and ¹H NMR spectroscopy. Their mesomorphism, thermodynamic properties and optical textures were investigated by differential scanning calorimetry, polarizing optical microscope and X-ray diffraction. For homologues with terminal propyloxy and butyloxy chains, no liquid crystalline phase was observed. Homologues with pentyloxy and hexyloxy terminal chains showed nematic phases, while those with heptyloxy, octyloxy, nonyloxy and decyloxy terminal chains displayed nematic phases and smectic phases. The results confirmed that the liquid crystalline phase changes from nematic to smectic as the terminal chain length increases.     

A convenient synthesis of enantiopure (4aS,7aR)-1,4,4a,7a-tetrahydrocyclopenta[c]pyran-3,7-dione

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New liquid crystalline 3-methyl-6-(4-substituted phenyl)-4,5-dihydrobenzo [ d ] isoxazoles and 3,5-disubstituted 4,5-dihydroisoxazoles: synthesis and mesomorphic properties

The synthesis and mesomorphic properties of new liquid crystalline 3-methyl-6-(4-substituted phenyl)-4,5-dihydrobenzo [ d ] isoxazoles and 3,5-disubstituted 4,5-dihydroisoxazoles are reported. These compounds have been synthesized by the reaction of 6-(4-substituted phenyl)-3-acetyl cyclohex-2-enones with hydroxylamine hydrochloride and of the corresponding oximes with unsaturated compounds in the presence of N -chlorosuccinimide and triethylamine, respectively.