Yu. Yu. Popelis

Asymmetric reduction of aromatic and hetero cyclic ketones by hydrosilylation and hydrogen transfer in the presence of optically active rhodium catalysts

A study has been made of enantioselective hydrosilylation and reduction, by hydrogen transfer, of prochiral alkyl phenyl ketones or alkyl hetaryl ketones over various optically active catalysts. A total of 14 aromatic and heterocyclic carbinols were synthesized with preparative yields of 54–100%. The most effective catalytic systems were found to be complexes of RhCl3 and [Rh(cod)Cl]2 with the known optical inductor (S,S)-i-Pr-Pybox, with which we have obtained for the first time a series of heterocyclic secondary alcohols with an enantioselectivity of 20–63%.

13C NMR spectra of 8-mercaptoquinoline and 8-hydroxyquinoline

The signals in the13C NMR spectra of quinoline and its 8-substituted derivatives (SH, SCH3, OH, OCH3, NH2, I, and CH3), 8,8′-diquinolyl disulfide, the 8-hydroxy-N-methylquinolinium ion, and the protonated and anionic forms of 8-hydroxy- and 8-mercaptoquinoline were assigned. The increments of the substituents in the neutral forms of these compounds correlate satisfactorily with those in substituted benzenes and the Swain-Lupton parameters (r = 0.94–0.99). The differences in the ortho increments of the substituents are due to a change in the electron densities on the carbon atoms and also to steric hindrance. The effect of an intramolecular hydrogen bond on the13C chemical shift of the quinoline ring of 8-hydroxy- and 8-mercaptoquinoline was examined. The13C chemical shifts correlate satisfactorily with the total charges (q) on the carbon atoms in the neutral forms of these compounds. A similar correlation is satisfied to a lesser extent for the protonated and anionic forms because of a change in the bond orders.

E-β-Styrylgermatrane

E-β-1-(2-Phenylethenyl)-2,8,9-trioxa-5-aza-1-germatricyclo[3.3.3.01,5]undecane (β-Styrylgermatrane) was obtained as the result of sequential reactions: the introduction of germanium dibromide at the C−Br bond of β-bromostyrene and the alcoholysis of tribromogermane to the triethoxy derivative with subsequent transetherification by triethanolamine. The structure ofβ-Styrylgermatrane and 2.215 Å length of the transannular N→Ge bond were established by the method of NMR and X-ray diffraction analysis. It was found that the introduction of the CH=CH portion between the aromatic ring and the atrane grouping lowers the toxicity of the compound by the factor of 40.

Dibenzodiazepines in reactions of 2-acetyl-dimedone with 3,4-diaminobenzophenone

The reactions of 2-acetyldimedone and 2-acetyl-3-methoxy-5,5-dimethylcyclohex-2-en-1-one with 3,4-diaminobenzophenoneproduce2-[1-(2-amino-5-benzoylphenyl)amino]ethylidene-5,5-dimethyl-1,3-cyclohexanedioneand 2-acetyl-3-(2-amino-5-benzoylphenyl)amino-5,5-dimethylcyclohex-2-en-1-one, which are cyclized by the action of hydrochloric acid, yielding the respective hydrochlorides of 8-benzoyl- and 7-benzoyl-3,3,11-trimethyl-2,3,4,5-tetrahydro-1H-dibenzo[b,e][1,4]diazepin-2-ones. Hydrolytic cleavage of the 8-benzoyl derivative leads to 2-acetyl-3-(2-amino-4-benzoylphenyl)amino-5,5-dimethylcyclohex-2-en-1-one. A similar cleavage to form 2-acetyl-3-(2-aminophenyl)amino-5,5-dimethylcyclohex-2-en-1-one is observed for the known hydrochloride of 3,3,11-trimethyl-2,3,4,5-tetrahydro-1H-dibenzo[b,e][1,4]diazepin-2-one. The structures of the products were confirmed by PMR spectra and x-ray diffraction data.

Synthesis and chemical properties of 8-aryl-7-acyl-1-6-dimethyl-6-hydroxy-4-cyano-5,6,7,8-tetrahydro-3(2H)-isoquinolinones and isoquinolinethiones

Abstract8-Aryl-7-acetyl-1, 6-dimethyl-6-hydroxy-4-cyano-5, 6, 7, 8-tetrahydro-3(2H)-isoquinolinones and -isoquinolinethiones and their sodium salts were obtained by the reaction of cyanoacetamide and cyanothioacetamide with 3-aryl-2, 4-diacetyl-5-methyl-5-hydroxycyclohexanonesinbasicrnedium. 8-Aryl-7-acetyl-6-methoxycarbonyl-1, 6-dimethyl-4-cyano-5, 6, 7, 8-tetrahydro-3(2H)-isoquinolinones were obtained by the reaction of acetyl chloride and the above isoquinolinone sodium salts. The reaction of iodoacetamide and the above isoquinolinethione sodium salts yielded 8-aryl-7-acetyl-3-carbamoylmethylthio-1, 6-dimethyl-4-cyano-5, 6, 7, 8-tetra-hydroisoquinolines, which were cyclized into 1-amino-6-aryl-7-acetyl-2-carbamoyl-5, 8-dimethyl-8-hydroxy-6, 7, 8, 9-tetrahydrothiophene[2,3-c]isoquinolines in basic medium.

O-Alkylation of furan and thiophene ketoximes in conditions of interphase catalysis in a liquid/solid system

Alkylation of 2 furanyl- and 2-thienylalkyl ketoximes with alkyl, allyl, and propargyl halides in the two phase catalytic system sol. K2CO3/C6H6/18-crown-6 at room temperature causes the formation of mixtures of E- and Z-isomers of the corresponding O-ethers with yields of 32–74%. Partial E/Z-isomerization takes place during the reaction.

1H, 1 3C, and 1 5N Chemical shifts and 1H-1 5N and 1 3C-1 5N heteronuclear spin-spin coupling constants in the NMR spectra of 5-substituted furfural oximes

The 1H, 13C, and 15N NMR spectra of 15N-enriched 5-substituted furfural oximes were investigated. It was shown that the chemical shifts of the ring atoms and the oxime group correlate satisfactorily with the F and R substituent constants, whereas their sensitivity to the effect of the substituents is lower than in monosubstituted furan derivatives. The constants of spin-spin coupling between the ring protons and the oxime group were determined. An analysis of the 1H-1H spin-spin coupling constants (SSCC) on the basis of their stereospecificity indicates that the E isomers have primarily an s-trans conformation in polar dimethyl sulfoxide, whereas the Z isomers, on the other hand, have an s-cis conformation. The signs of the direct and geminal 13C-15N SSCC were determined for 5-trimethylsilylfurfural oxime.

Synthesis of 2-(pyridylazo)-2-furyl-and 2-(pyridylazo)-2-thienylmethines and other heterocyclic Schiff bases in the presence of molecular sieves

The reactions of 2-furaldehyde, 2-thiophenecarbaldehyde, and their 5-methyl derivatives with 2-aminopyridines and some other amines in the presence of molecular sieves as a dehydrating agent and acid catalyst have been studied. A series of new heterocyclic azomethines was synthesized. Proposals were made for the mechanism of the condensation involving 2-aminopyridines and the structure of the intermediates in these processes.

Alkylation of hetaryl methyl ketones by propargyl bromide under phase-transfer catalysis conditions

The alkylation of aryl and hetaryl methyl ketones by propargyl bromide using the phase-transfer catalysis system KOH (s)/18-crown-6/benzene is studied. The corresponding C-trialkylated products are selectively obtained in 34–78% yields.

Synthesis and conversions of 2-acetyl-5-methyl-4-nitrofuran. Isomerization and beckman rearrangement of the oxime

Abstract2-Acetyl-5-methyl-4-nitrofuran and 3,5-dinitro-α-methylfuran were obtained by the reaction of 70% nitric acid with 2-acetyl-5-methylfuran, its oxime and semicarbazone in concentrated H2SO4. ω-Bromonitro ketone and a series of 5-methyl-4-nitro-2-furyl-substituted azaheterocyclic compounds based on it were obtained.