Syntheses based on norfluorocurarine. 4. Reactions with hydroxylamine

Transformation products of the alkaloid (–)-norfluorocurarine with hydroxylamine were studied. The oxime of norfluorocurarine was obtained and converted by treatment with EtOH into 2-hydroxy-16-cyano-2,16dihydronorfluorocurarine. The structures of 2-hydroxy-16-cyano-2,16-dihydronorfluorocurarine and 16-cyanonorfluorocurarine hydrochloride were established by XSA and NMR spectroscopy. The absolute structure of 2-hydroxy-16-cyano-2,16-dihydronorfluorocurarine was established and enabled the configurations of the asymmetric centers to be determined as 2R, 3S, 7R, 15S, and 16R.     

Syntheses based on norfluorocurarine. 6. Reaction with phenylhydrazine

The indole alkaloid norfluorocurarine was reacted with phenylhydrazine. An x-ray crystal structure analysis found that the phenylhydrazine was bonded through its N atoms to C2 and C17 and that the N1–C2 bond of the indole core was cleaved to form an NH₂ group and a water molecule was released.     

Syntheses based on norfluorocurarine. 2. Reduction and dehydrogenation products

The bisindole compound 2β,16α,2′β,16′β(H)-tetrahydronordihydrotoxiferine consisting of two diastereoisomeric deoxytetrahydronorfluorocurarine moieties was isolated from the reduction mixture of the alkaloid norfluorocurarine. 16-Deformyl-2,16,17,20-tetrahydro-20,21-dehydronorfluorocurarine was produced by dehydrogenation of norfluorocurarine; N(β)-methyldihydrodefluorocurarine, by hydrogenation of fluorocurarine. The structures of the synthesized compounds were established by x-ray structure analyses. The configurations of the asymmetric centers in 2β,16α,2′β,16′β(H)-tetrahydronordihydrotoxiferine were determined as 2S,3S,7R,15S,16R,2′S,3′S,7′R,15′S,16′S. Inversion to the R-configuration at the C15 center was observed in N(β)-methyldihydrodefluorocurarine whereas the configurations 3S and 7R were retained. Atom C2 adopted the S-configuration in 16-deformyl-2,16,17,20-tetrahydro-20,21-dehydronorfluorocurarine.     

Syntheses and 13C NMR spectra of fluorinated adamantane derivatives

The syntheses of a variety of fluorine-containing adamantane derivatives are described. The ¹³C NMR spectra of those compounds with different configurations are interpreted in terms of through-bond and through-space substituent interactions.     

Syntheses based on norfluorocurarine. 3. Structures of (−)-norfluorocurarine, (±)-norfluorocurarine,and fluorocurarine

Structures of the alkaloids (−)-norfluorocurarine, its racemate (±)-norfluorocurarine from Vinca erecta, and fluorocurarine obtained by N(β)-methylation of (−)-norfluorocurarine were established by x-ray crystal structure analyses. The alkaloid crystallized with two molecules in the asymmetric unit for the first two crystals. The asymmetric unit of (±)-norfluorocurarine crystal consisted of two antipods. The asymmetric unit in the crystal of the last compound consisted of the N(β)-methylated cation and a hydroxide anion. The formation of bimolecular associates through intermolecular N–H…O H-bonds was typical of these crystal- line structures. An associate in the crystal structure of fluorocurarine involved two hydroxide anions.     

NMR spectra of natural coumarin derivatives

Conclusions The NMR spectra of nine coumarin derivatives have been studied. The results obtained may be used for purposes of structural analysis.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 6–14, 1970     

NMR spectra of natural coumarin derivatives

Chemistry of Natural Compounds - The NMR spectra of nine coumarin derivatives have been studied. The results obtained may be used for purposes of structural analysis.     

Fluorine NMR spectra of pentafluorophenyl derivatives

The fluorine chemical shifts and spin-spin coupling constants of 65 pentafluorophenyl derivatives with widely varying organic substituents were examined. Useful correlations of the three meta coupling constants with the chemical shifts of the para fluorine were found. It is suggested that these relationships be extended to all compounds of the type considered in order to determine the signs and approximate values of meta coupling constants. Equations for correlation of the fluorine chemical shifts with the Taft constants are presented. The possibility of calculating the Taft constants from the ¹⁹F NMR spectra of pentafluorophenyl compounds is being discussed.     

13C NMR spectra of adamantane derivatives

The carbon-13 chemical shifts of mono- and 1,3-disubstituted adamantanes are reported. The effects caused by the substituents are compared with those met in aliphatic and alicyclic compounds. It is shown that the 1,4-interactions have only minor importance in l-substituted adamantanes. The influence of polar groups on the chemical shifts of γ- and δ-carbon atoms is a typical ‘through-the-bonds’ interaction and correlates with inductive parameters of the substituents.     

Syntheses based on 5-methylfurfural

Conclusions A series of derivatives of furan and tetrahydrofuran were synthesized on the basis of 5-methylfurfural: alkyl(5-methylfuryl)carbinols, alkyl(5-methyltetrahydrofuryl)carbinols, 2-methyl-5-alkenylfurans, 2-methyl-5-alkylfurans, and 2-methyl-5-alkyltetrahydrofurans.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 1829–1831, October 1966.     

Pyrimidines. 75. Syntheses based on acetylpyrimidines. 4,6-Dihydroxy-5-acetylpyrimidine and preparation of 4′,5-bipyrimidines and their derivatives

4,6-Dihydroxy-5-acetylpyrimidine was obtained by the solvolysis of 4,6-dialkoxy-5-acetylpyrimidines. The hydrolysis of 4,6-dichloro-5-acetylpyrimidine leads to opening of the heteroring to give s-cis,trans conformera of 2-cyano-3-hydroxy-2-buteneamide. 2,4,6-Trihydroxy[4,5]bipyrimidine was obtained by the condensation of 4,6-dialkoxy-5-acetylpyrimidines with benzalbisurea. It is shown that the products of the reaction of the same ketones with benzaldehyde in the presence of sodium alkoxides are derivatives of -diketones.See [1] for Communication 74.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 378–385, March, 1985.