Chemistry of 1,5-diketone derivatives. 1. Oxidation of 8a-methoxy-4a,5,6,7,8,8a-hexahydrochromenes by monoperphthalic acid

2-(2-Oxo-3-hydroxy-1,3-diphenylpropyl)cyclohexanone, 2-(2,3-dioxo-1,3-diphenylpropyl)cyclohexanone, and 2-benzyl-7a-hydroxy-3-phenylperhydrobenzofuran are formed by the action of monoperphthalic acid on 8a-methoxy-2,4-diphenyl-4a,5,6,7,8,8a-hexahydrochromene. Under analogous conditions, 4a-methoxy-10-phenyl-1,2,3,4, 4a,6,7,8,9,10a-decahydroxanthene forms 7a-hydroxy-3-phenyloctahydrobenzo[b]furan-2-spiro-1-cyclohexan-2-one and its dehydration product. The behavior of the compounds obtained toward acetic anhydride and a methanolic solution of HCl was studied. The configurations of the reaction products and the reaction path are considered.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 177–181, February, 1985.     

Reactions of pyrrolidine enamines of cyclic and acyclic 3,4-dioxobutanoic acid Derivatives with dimethyl acetylenedicarboxylate. A new case of atropoisomerism.

Reaction conditions and structure of the starting enamines (cyclic or open-chain) determine greatly the final products of the title reactions. Whereas in benzene and acetonitrile, DMAD and 1 give a mixture of the diastereoisomeric dienamines 5, in methanol they afford pirrolizine 3. Enaminofuranones 2 and 10 furnish the corresponding “Michael adducts” 7a,b,c and 11a,b,c but fail to yield pirrolizines. It has been demonstrated that above b and c adducts differ exclusively on the arrangement of groups around a chiral axis.     

Influence of cation structure on decomposition of diacyl peroxides activated by chloride salts of amines

A kinetic study has been made of the interaction of benzoyl peroxide with a number of chloride salts of amines. It is shown that a change of the cation in quaternary ammonium salts does not have any significant effect on the kinetic parameters of the reaction. By means of NMR spectroscopy it has been determined that the structure of the NR₄ ⁺ cation does not change during the course of the reaction. The role of the cation in the process of activation of a diacyl peroxide by chloride salts of amines has been investigated by means of MNDO calculations.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 4, pp. 324–328, July–August, 1992.     

Carbohydrates of cultivated varieties ofAlthea rosea

The polysaccharides of three cultivated varieties ofAlthea rosea have been investigated. The amounts of water-soluble polysaccharides and pectin substances in various organs of the plant have been determined. It has been shown that the maximum amount of water-soluble polysaccharides and pectin substances is present in the flowers. Their monosaccharide compositions have been studied. The physicochemical characteristics of the pectin substances are given.     

L-asparaginase bound in a polyacrylamide gel

Summary The enzyme L-asparaginase fromE. coli has been included in polyacrylamide gel, and some of its properties have been investigated: stability, pH dependence, heat stability, K_m. It has been shown that the enzymegel obtained has a better stability then the native enzyme.Institute of Organic Synthesis, Academy of Sciences of the Latvian SSR, Riga. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 382–384, May–June, 1976.     

Gitoxigenin glycosides

Summary Three cardiac glycosides have been synthesized from gitoxigenin and D-glucose: gitoxigenin 3-O--D-glucopyranoside, gitoxigenin 16 -O- -D-glucopyranoside, and gitoxigenin 3, 16-di-O- -D-glucoside. The first glycoside, obtained with a yield of 49% on the weight of the initial aglycone, possesses a fairly high biological activity (0.25 mg/kg), while the other two, formed in a yield of about 0.3%, do not possess the action on the heart that is specific for the cardenolides.Khar'kov Chemical and Pharmaceutical Scientific-Research Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 45–49, January, 1971.     

Reaction of nitroform with vinylacetic acid

Conclusions The reaction of nitroform with vinylacetic acid has given-methyltrinitrobutyric acid. Some derivatives of this acid have been obtained.Translated from Izvestiya Akademii Nauk SSSR Seriya Khimicheskaya, No. 6, pp. 1351–1353, June, 1967.     

Structure and reactivity of the condensation products of aromatic amines with aliphatic aldehydes

A number of previously undescribed propylidenearylamine dimers have been synthesized by the interaction of propionaldehyde with a series of para-substituted anilines(R=H, CH₃, OCH₃, F, Cl, Br, I) and with-naphthylamine. The structure of the bis-propylidenearylamines has been established by a study of their IR and UV spectra. It has been shown that all the bis-propylidenearylamines, except for bis(propylidene-p-fluoroaniline), have the structure of 2-ethyl-3-methyl-4-arylamino-1, 2, 3, 4-tetrahydroquinolines. The dipole moments of the bis(propylidene-p-R-anilines) have been determined. Comparison of the values obtained with the calculated values indicates that the most favorable molecular conformation of the bispropylidenearylamines is a tetrahydroquinoline half-chain with quasi-equatorial positions for the 4-NHAr and NH groups and an equatorial 3-CH₃ group. In contrast to the bis-ethylideneanilines, we did not succeed in finding other stable conformers for the bis-propylidene derivatives. It has been established that bis (propylidene-p-fluoroaniline) has the 1, 3-bis (p-fluorophenylamino)-2-ethyl-1-hexene structure.For communication VI, see [1].     

Tautomeric equilibrium of 1-β-D-ribofuranosyl-2-keto-4-(n-methoxyamino)pyrimidine

The 1-β-D-ribofuranosides of 2-keto-4-(N-methoxyamino)pyrimidine, 2-keto-4-(N-methyl-N-methoxyamino)pyrimidine, and 2-keto-3-methyl-4-(N-methoxyamino)pyrimidine were synthesized, and their pK_a values were determined by spectrophotometry. The pK_a values of the compounds are evidence that the tautomeric equilibrium between the oxime and hydroxyamine forms of 1-β-D-ribofuranosyl-2-keto-4-(N-methoxyamino)pyrimidine in aqueous solutions is shifted to favor the oxime form (K_T?25).     

Ionotropic reactions of β-sultones

The reaction mechanism of-sultones are discussed; a scheme for the reactivity is proposed. Polyfluoro--sultones can undergo anionotropic reactions of the type Hydrogeneous-sultones under prototropic reactions: