Vol 53, No 3 (2017)

An efficient procedure has been developed for the synthesis of N,N′-(2,5-dithiaalkane-α,ω-diyl)bis-(N′-allylthioureas) by thiomethylation of N-substituted ureas and thioureas with α,ω-alkanedithiols and N,N,N′,N′-tetramethylmethanediamine in the presence of cesium carbonate as catalyst.

Hydrolytic cleavage of cage γ-sultones have been studied. Alkaline hydrolysis of homoadamantane γ-sultone leads to the formation of sulfonates with erythro configuration. The reduction of homoadamantane γ-sultone with LiAlH₄–AlCl₃ yields desulfurization and deoxygenation products.

A procedure is described for the synthesis of lactide by dehydration of L-lactic acid and subsequent depolymerization of its oligomer mixture in the presence of yttrium(III) and praseodymium(III) oxides, as well as of cerium(III) chloride heptahydrate. The catalytic activity of yttrium and praseodymium sesquioxides was determined at different temperatures at the oligomerization and deoligomerization stages. Ethyl lactate was prepared in the presence of Purolite C100 MB cation exchange resin and subjected to oligomerization followed by thermal decomposition of oligoester and oligolactic acid mixture in the presence of yttrium(III) and praseodymium(III) oxides and aqueous cerium(III) chloride.

Alkyl biphenyl-4-carboxylates have been synthesized with high selectivity by multicomponent reaction of biphenyl with carbon tetrachloride and aliphatic alcohols in the presence of iron-containing catalysts.

New hetarylethenes, 3-(indol-3-yl)-4-thienyl(but-1-en-1-yl)-substituted pyrrole-2,5-diones containing coumarin or fluorene substituents on the pyrrole nitrogen atom, were synthesized by reactions of furan-2,5-diones with 9H-fluoren-2-amine and 6-amino-2H-chromen-2-one. Acyclic maleimide isomers showed fluorescence with quantum yields of 0.002 to 0.072. Their irradiation with UV light generates non-fluorescing cyclic isomer. The reverse ring opening occurs in the excited state.

The keto group in the carbohydrate residue of diastereoisomeric Michael adducts of levoglucosenone and cyclohexanone is more reactive than that in the cyclohexanone fragment. The adducts have been converted to the corresponding ethylene, trimethylene, and dimethyl ketals, tosylhydrazones, oxiranes, and Wittig methylenation products with complete or high regioselectivity.

Diphenyldiazomethane and 9-diazofluorene react with phenylethynyl trifluoromethyl sulfone in diethyl ether at 20°C to give 1,3-dipolar cycloaddition products according to the von Auwers rule, the corresponding 3H-pyrazoles. The adduct with diphenyldiazomethane undergoes thermal van Alphen–Hüttel rearrangement to 4,4,5-triphenyl-3-(trifluoromethanesulfonyl)-4H-pyrazole on heating in boiling benzene. Under analogous conditions, the adduct with 9-diazofluorene is converted into 3′-phenylspiro[fluorene-9,4′-pyrazol]-5′(1′H)-one, whereas 3a-phenyl-2,3a-dihydro-3H-dibenzo[e,g]indazol-3-one is formed in boiling methanol. The structure of 3′-phenylspiro[fluorene-9,4′-pyrazol]-5′(1′H)-one was determined by X-ray analysis.

1-Aryl-4-chloro-5-(2-nitroethenyl)-1H-imidazoles reacted with thiols and aromatic amines via Michael addition to give 5-[(1-arylsulfanyl)-2-nitroethyl)]-4-chloro-1H-imidazoles and N-[1-(1-aryl-4-chloro-1H-imidazol-5-yl)-2-nitroethyl]anilines, respectively. [2 + 3]-Cycloaddition of the title compounds to sodium azide afforded 4-(4-chloro-1H-imidazol-5-yl)-1H-1,2,3-triazoles.

Reactions of tryptanthrin with acetone, cyclopentanone, hexan-2-one, 4-methylpentan-2-one, 4-hydroxy-4-methylpentan-2-one, cyclohexanone, and butan-2-one in the presence of potassium carbonate afforded racemic phaitanthrin A and other addition products to the ketone group of tryptanthrin with high yields. Thermal dissociation, some chemical transformations, and antimicrobial activity of some adducts were studied, and inhibitory effect against gram-positive bacteria was found for particular derivatives.

Acylation and cyclization reactions of 4-amino-5-(1,4-benzodioxan-2-yl)-4H-1,2,4-triazole-3-thiol were studied. Acylation of the title compound with substituted benzoyl chlorides gave the corresponding amides, whereas its reactions with substituted benzoic acids in the presence of POCl3 were accompanied by cyclization with formation of triazolothiadiazoles containing a 1,4-benzodioxane substituent. 4-Amino-5-(1,4-benzodioxan-2-yl)-4H-1,2,4-triazole-3-thiol reacted with substituted benzaldehydes to afford the corresponding Schiff bases, and its alkylation with chloroacetic acid in ethanol in the presence of sodium acetate gave S-ethoxycarbonylmethyl derivative.

New 1′,1′-dimethyl-2′,5′-dihydro-1′H-pyrrolo[3′,4′:1,9](C₆₀-I_h)[5,6]fulleren-1-ium iodides containing different aryl groups in position 2 of the pyrrolidine ring have been synthesized. Their reactions with bis-(toluene)chromine afforded the corresponding 3′-aryl-3′H-cyclopropa[1,9](C₆₀-I_h)[5,6]fullerenes.

Three-component reaction of indole, aromatic aldehyde, and N,N-dimethyl aniline in the presence of silica-supported Fe(ClO₄)₃ as catalyst afforded the corresponding 3-[aryl(4-dimethylaminophenyl)methyl]-indoles in excellent yields under mild conditions. The proposed protocol offers some remarkable advantages such as the use of a solid catalyst and simple workup procedure.

A simple laboratory procedure has been proposed for the synthesis of tetracyanoethylene in up to 54% yield by oxidative dimerization of malononitrile in the presence of selenium(IV) oxide.

An efficient procedure has been proposed for the synthesis of previously unknown 1-hydrazinylanthraquinones containing acyl and/or ester fragments convenient for subsequent transformations.

Epimeric mono- and bis-sulfoxides synthesized by oxidation of 8-methyl-5-(methylsulfanylmethyl)-3-thiabicyclo[3.3.1]non-7-en-6-one were separated by silica gel column chromatography. Their threo and erythro isomers were distinguished by signals of diastereotopic protons of the exocyclic methylene group.

1-Ethyl-6-methoxy-3-methyl-1H-1,2-diazaphenalene was readily acylated with trifluoroacetic anhydride with formation of 1-ethyl-6-methoxy-3-methyl-7,9-bis(trifluoroacetyl)-1H-1,2-diazaphenalene.

A convenient procedure was developed for the synthesis of 2-azidobicyclo[2.2.1]heptane whose click reaction with phenylacetylene afforded 1-(bicyclo[2.2.1]heptan-2-yl)-4-phenyl-1H-1,2,3-triazol, and its reactions with ethyl α-bromoacrylate and ethyl acetoacetate gave 1-(bicyclo[2.2.1]heptan-2-yl)-5-R-1H-1,2,3-triazole-4-carboxylic acids.