Five-, Six-, and Seven-membered Lactim Ethers. Methods of Synthesis and Chemical Properties. (Review)

Data on methods for the production of 5–7-membered lactim ethers and their chemical transformations published after 1970 are reviewed.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 645–690, May, 2005.     

Extraction by reversed micelles of triton N-42 for the spectrophotometric determination of cetyltrimethylammonium bromide

Micellar preconcentration of 1 : 2 associates of Bromophenol Blue with cetyltrimethylammonium bromide is proposed to improve the procedure for the spectrophotometric determination of cationic surfactants. The preconcentration procedure involves quantitative extraction by reversed micelles of Triton N-42 in decane followed by the decomposition of the micellar solution with chloroform. The loss of 10^–7–10^–5 M cetyltrimethylammonium bromide in 5–100-fold preconcentration was not supported by the added-found method (RSD = 3–5%). The determination limit for cetyltrimethylammonium bromide is 2 × 10^–7 M.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 1, 2005, pp. 17–21.Original Russian Text Copyright © 2005 by Demidova, Bulavchenko.     

Synthesis of a decapeptide with the sequence 1–10 of human calcitonin with minimum protection of the amino acids

A decapeptide with sequence 1–10 of human calcitonin has been synthesized by a 5+5 scheme with the minimum protection of the side-chain functional groups of the amino acid.All-Union Scientific-Research Institute of the Technology of Blood Substitutes and Hormonal Preparations, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 381–387, May–June, 1985.     

Comparative study on the determination of cephalexin in its dosage forms by spectrophotometry and HPLC with UV-vis detection

This paper discusses the spectrophotometric determination of cephalexin as the intact cephalexin or as its acid-induced degradation product. Cephalexin can be determined in the range 1 × 10^–5–18 × 10^–5 M with relative standard deviations of 5-1%. The limits of quantitation and detection were 10^–5 and 0.3 × 10^–5 M, respectively. These procedures were compared with reversed-phase HPLC determination. No interference was observed in the presence of common pharmaceutical adjuvants. The H-point standard additions method was applied in order to correct for the possible presence of the cephalexin precursor, 7-aminocephalosporanic acid; this improves the selectivity of the UV-vis spectrophotometric method.     

Thermal decomposition rate of tetraphenylhydrazine in inert solvents

Conclusions The decomposition of tetraphenylhydrazine in inert media at 348°K proceeds not as an induced, but instead as a pseudomonomolecular process, with decomposition rate constants of 6.3 · 10^–5 and 8.6 · 10^–5 sec^–1 in CCl₄ and n-heptadecane, respectively.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1629–1631, July, 1982.     

Crystal and molecular structure of 1,3-di(2,2,6,6-tetramethyl-1-oxyl-4-carbpiperidyloxy)Adamantane

Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 5, pp. 150–153, September–October 1991.     

Synthesis of homologs of pyrrole and pyrrolidine

Conclusions 1-(5-Methylfuryl)-3-aminoalkanes on vapor phase hydrogenation over Pt/C at 220–270° are converted into pyrrole and pyrrolidine homologs in 60–70% yield.Translated from. Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 210–213, January, 1968.     

Synthesis of protoberberine alkaloids

In this review an analysis is made of literature information on the synthesis of protoberberine alkaloids during 1980–1990.Institute of Chemistry of Plant Substances, Uzbekistan Republic Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 449–468, September–October, 1992.     

Selective acid hydrolysis of 2-substituted-5-dimethylaminomethyleneaminopyrimidines to 5-amino- and 5-hydroxypyrimidines

Conditions are described for the selective acid hydrolysis of 2-substituted-5-dimethylaminomethyleneaminopyrimidines in 0.2–2 M sulfuric acid, to give high yields of the corresponding 5-amino- and difficultly accessible 5-hydroxypyrimidines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 801–803, June, 1990.     

Ultraviolet absorption of flavonoids

Conclusions The ionization constants of the 5-hydroxy groups in tectochrysin and chrysin have been determined spectrophotometrically, being 2.09×10^–12 and 8.91×10^–10, respectively. The 7-hydroxy group of chrysin has an ionization constant of 3.8 × 10^–8.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 24–27, 1970     

Arcutin — A new type of diterpene alkaloids

The structure of the diterpene alkaloid arcutin, which is isolated fromAconitum arcuatum Maxim. (Ranunculaceae), is solved by x-ray methods. Arcutin represents a new type of diterpene alkaloids containing a C5–C20 bond instead of the traditional C10–C20 bond in the carbon backbone.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 62–65, January–February, 2000.     

Aqueous fluorination of substituted phenyldinitromethyl anions

Conclusions Various substituted nitrophenylfluorodinitromethanes were obtained by aqueous fluorination in the temperature range 5–50°.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1424–1425, June, 1973.     

Chemical investigation of the polysaccharides of the leaves ofPlantago major L.

Summary 1. Pectic acid contains galacturonic acid (78–83%) and, chemically linked with it, the monosaccharides D-galactose, L-arabinose, L-rhamnose, and substance (VIII) and (IX).2. By fractionating the polysaccharide complex of the leavesof Plantago major L. on a DEAE-cellulose column it has been shown that it consists of pectic acid (80–82%), and free galactoraban (5–6%) and galactan (4–5%).Khimiya Prirodnykh Soedinenii, Vol. 1, No. 6, pp. 369–372, 1965.We have used Kertesz's nomenclature of pectic compounds [4].     

Additive-multiplicative relationship for chemical interaction energy and calculation of the energy of chemical bond dissociation to neutral atoms

Samara State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 5, pp. 137–140, September–October, 1992.     

Influence of instrument background on magnitude of structural parameters and composition of vapor as determined by gas-phase electron diffraction

Ivanovo Chemical Technology Institute. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 5, pp. 55–62, September–October, 1992.     

Chemical transformation of ecdysteroids: Latest advances

In this review the results of chemical transformations of ecdysteroids reported in the literature during 1986–1996 are discussed.Institute of Bioorganic Chemistry of the Belarus Academy of Sciences, 220141, Minsk, Zhodinskaya, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 139–160, March–April, 1998.     

Chemical transformations of 6-[(1-methyl-4-nitro-5-imidazolyl)-thio]purine (azathioprine)

The chemical transformations of 6-[(1-methyl-4-nitro-5-imidazolyl)thio]purine (azathiopurine) —hydrogenation, acetylation, alkylation by lower alkyl halides at positions 7 and 9 of the purine ring, hydrolytic cleavage at the C₍₆₎–S and S–C₍₅₎ bonds— were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 372–379, March, 2000.     

Dipole moments,kerr constants,and conformations of some substituted methyl cyclopropyl ketones

Conclusions The acetyl group in a substituted cyclopropane ring has an s-cis conformation that is distorted by either 15–20° (cis-2-halo-cis-3-methyl derivatives) or by 55–70° (cis-2-halo-1-methyl derivatives).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1174–1177, May, 1977.     

Organoboron compounds

Conclusions The B-C bond in organoboron compounds is smoothly protolyzed by NaOH in ethylene glycol at 135–200°C.Translated from Izvestiya Akademiya Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1126–1128, May, 1977.     

Reaction of 1-bromo-2-acylacetylenes with thiobenzhydrazide

Conclusions The reactions of 1-bromo-2-acylacetylenes with thiobenzhydrazide at from –10 to –30°C in ether, acetonitrile, methanol without catalyst, or methanol in the presence of triethylamine gave 2-acylmethyl-5-phenyl-1,3,4-thiadiazoles and their hydrobromide salts.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2637–2638, November, 1988.