Volume 53, Nº 10 (2017)

Tautomers of N-allyl- and N-propargyl-substituted trifluoromethanesulfonimides (CF₃SO₂)₂NR (R = CH₂CH=CH₂, Z/E-CH=CHMe, CH₂C≡CH, CH=CH=CH₂, C≡CCH₂) were calculated by the DFT (B3LYP, wB97XD, PBE1PBE), MP2, and CBS-QB3 methods. The results were compared with the theoretical data for the corresponding amines and amides NHRR¹ (R¹ = H, CF₃SO₂). It was shown that there is no conjugation between the nitrogen atom and C=C bond and that conjugation exists with the C≡C bond with electron density displacement toward the nitrogen atom. The calculations of anions derived from N-allyl- and N-propargyl-trifluoromethanesulfonimides revealed the possibility of their rearrangement with elimination of trifluoromethanesulfinate anion and formation of its H-complex with N-(prop-2-en-1-ylidene)trifluoromethanesulfonamide or N-(prop-2-yn-1-ylidene)trifluoromethanesulfonamide.

α-Alkyl-, α-arylalkyl-, and α-aryl-substituted benzyl alcohols were converted into the corresponding symmetrical dibenzyl ethers in the presence of a catalytic amount of 10% aqueous HCl both in methylene chloride and under solvent-free conditions. Analogous reactions in dioxane and on heating afforded mainly the corresponding arylalkenes, whereas symmetrical dibenzyl ethers were formed as minor products.

Reactions of syn- and anti-4-(4-bromophenyl)-2-methylnon-1-en-5-ols and 3-(4-bromophenyl)-5- methyl-1-phenylhex-5-en-2-ols with trifluoromethanesulfonic acid and salicylaldehyde derivatives in the presence of Et₂O · BF₃ (Prins reaction) or with salicylaldehydes in the presence of trimethyl orthoformate and p-toluenesulfonic acid stereoselectively afforded tri- and tetrasubstituted tetrahydrofurans with one or two fused heterocycles and various functional groups (COOEt, Br, MeC=CH₂). The reactivity of the synthesized compounds toward thiophen-2-ylboronic acid in the Suzuki reaction was studied, and hydrolysis and reduction (LiAlH₄) of the ester group therein gave the corresponding carboxylic acids and alcohols. One of the obtained tetrahydrofuran derivatives was converted into amide, aldehyde, and aldehyde oxime. Stereochemical configuration of substituents was retained in all chemical transformations.

6-(Dimethylamino)fulvene reacted with 3- and 4-substituted 5-diazoazoles, as well as with 4-substituted benzene- and pyrazole-5-diazonium salts, in an aprotic solvent with high regioselectivity at an extremely high rate to give acyclic coupling products at the α-carbon atom of the cyclopenta-1,3-diene fragment. The nature of the diazo component did not affect the reaction direction, rate, or yield. Hydrolysis of the azo compounds obtained from arenediazonium salts involved elimination of the dimethylamino group with formation of aldehydes, and their reaction with pyrrolidine resulted in replacement of the dimethylamino group by pyrrolidine ring.

The alkylation of ambident anions of 2-(methylsulfanyl)-6-(polyfluoroalkyl)pyrimidin-4(3H)-ones with 4-bromobutyl acetate leads to concurrent formation of O- and N-(4-acetoxybutyl) derivatives. Polar aprotic solvents favor formation of the O-isomer, and weakly polar dioxane favors N-alkylation. The reaction of 2-(methylsulfanyl)-6-(trifluoromethyl)pyrimidin-4(3H)-one with an equimolar amount of 1,2-dibromoethane in polar acetonitrile gives a mixture of N,N-, O,O-, and N,O-bridged bis-pyrimidines, as well as N- and O-[2-(methylsulfanyl)ethyl] derivatives, whereas in the presence of 10 equiv of 1,2-dibromoethane the N,O-isomer is formed as the only product. The reaction in weakly polar tetrahydrofuran yields N,N- and N,O-bispyrimidines.

4-(2-Hydroxyphenyl)-1,3,5-triazin-2-ylcyanamides reacted with sodium azide to give N-(tetrazol-5-yl)-1,3,5-triazin-2-amines, and their reaction with allyl bromide afforded allyl(1,3,5-triazin-2-yl)cyanamides. Acetylation of 4-(2-hydroxyphenyl)-1,3,5-triazin-2-amines involved only the amino group with formation of diacetylamino derivatives, whereas the phenolic hydroxy group remained intact. The reaction of triazinamines with 2,5-dimethoxytetrahydrofuran in the presence of P₂O₅ gave pyrrolyl-substituted triazines.

The Bingel–Hirsch reaction of (R)-2,2-dichloro-N-(1-phenylethyl)acetamide with fullerene C₆₀ gave the corresponding methanofullerene, and its electrochemical and physical properties were studied. The electron-acceptor characteristics of the new compound were found to be similar to those of the known methanofullerene [60]PCBM.

A procedure has been developed for the synthesis of cyclohexyl isovalerate by reaction of isobutylene with carbon monoxide and cyclohexanol in the presence of the three-component catalytic system Pd(PPh₃)₄‒PPh₃‒TsOH. Cyclohexyl isovalerate showed a pronounced antibacterial activity.

4-Oxoalkane-1,1,2,2-tetracarbonitriles in the presence of an equimolar amount of morpholine were converted to previously unknown 2-(5-aryl-4-methyl-2-oxo-1,2-dihydro-3H-pyrrol-3-ylidene)malononitriles.

The aza-Michael reaction of 3,5-dimethylpyrazole with crotonaldehyde in water involved addition of two aldehyde molecules with formation of 2-[2-(3,5-dimethyl-1H-pyrazol-1-yl)propyl]-6-methyl-1,3-dioxan-4-ol. The latter exists in solution as equilibrium mixture with monocyclic 3-{[3-(3,5-dimethyl-1H-pyrazol-1-yl)-1-hydroxybutyl]oxy}butanal.