Transformations of some alkaloids of the carboline series under the influence of alkali

The reaction of quaternized forms of two alkaloids of the -carboline series — harman and brevicarine — with alkali was investigated. It was established that, under the reaction conditions, the harman derivative undergoes recyclization of the pyridine part of the molecule, whereas in the analogous brevicarine derivative the pyridine ring does not undergo transformations.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 530–533, April, 1985.     

Reaction of 1,2,3,4-tetrahydro-2,4,5-trimethylpyrrolo[1,2-c]pyrimidine and its 7-formyl-substituted derivative with nitric acid

1,2,3,4-Tetrahydro-2,4,5-trimethylpyrrolo[1,2-c]pyrimidine and its 7-formyl derivative when treated with nitric acid are converted to substituted tetrahydropyrrolo-[1,2-c]pyrimidine-7-carboxylic acid. Conversion occurs through opening of the aminal moiety and formylation of the second molecule of tetrahydropyrrolo[1,2-c]pyrimidine by formaldehyde formed to the 7-formyl-substituted derivative.Russian University of International Friendship, Moscow 117198. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp 219–222, February, 1999.     

Spectroscopic studies of the behaviour of the AgNO3−HNO3 — Tetrabutyl dithiopyrophosphate extraction system

A very efficient extraction of silver with tetrabutyl dithiopyrophosphate (TBDTPP) is followed by dramatic changes in the structure of the extractant molecule. The IR and NMR spectroscopic studies have revealed that in the presence of Ag⁺ and NO ₃ ^– ions the TBDTPP molecule rearranges first into a molecule containing a P–S–P bridge and one P=O group instead of P–O–P and P=S, respectively, and then into a molecule containing two P–S–C and two P=O groups at a P–O–P bridge.     

The action of acetic anhydride on N-methyltryptophans

Summary A new furocoumarin of composition C₂₁H₂₂O₇ has been isolated from the fruit ofLibanotis transcaucasica Schischk. It has been established that libanotin is a derivative of 8-isopropyloxy-8,9-dihydroangelicin. The side groups of libanotin — acetic and 2-methyl-cis-crotonic acids — are attached to the main part of the molecule by ester bonds.Khimiya Prirodnykh Soedinenii, Vol. 1, No. 3, pp. 215–220, 1965     

Oxidative cyclization of 4-arylthio-semicarbazones

2-Benzothiazolylhydrazones were synthesized by the action of bromine on 4-arylthiosemicarbazones. The imino structure of the cyclization products was demonstrated by comparison of the UV spectra of the hydrazones and the methylation product. Cyclization to the thiadiazole derivative was noted when bromine was present in the aryl ring of the thiosemicarbazone. A dimethylamino group in the aldehyde portion of the molecule prevents cyclization.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1330–1332, October, 1970.     

Transformed steroids

Conclusions The enamination of the 21-hydroxymethylene derivative of the 16,17-dehydropregnenolone under conventional conditions is accompanied by the C-alkylation of the intermediate enamino ketone by a second molecule of the starting -keto aldehyde.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 431–434, February, 1974.     

The mass spectra of some 1,3,2-oxazaphospholanes

The mass spectra of six 1,3,2-oxazaphospholanes have been obtained. The compounds studied give strong m/e=M lines; the relative stability of the molecular ion correlates with the structure of the molecule. During the process of dissociative ionization, cleavage of the C-C and the P-O bonds in the ring takes place, with the molecular ion losing a R'CHO molecule. It has been shown that the molecule of an olefin is formed from the molecular ion mainly through an alkoxy group. A probable process of dissociative ionization is the loss by the molecular ion of an alkoxy group or, in the case of the 2-chloro derivative, the loss of a Cl atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 894–897, July, 1973.     

Chlorination and oxidation of some sulfurcontaining tetrachloropyridine derivatives

In the chlorination of 4-methyl- and 4-chloroformylmethylenethiotetrachloropyridines, the chlorine atom enters the methyl or methylene group. In the case of the 4-(p-chlorobenzyl)-thio derivative, the molecule is cleaved to give tetrachloropyridine-4-sulfenyl chloride. Hydrogen peroxide oxidizes substituted benzyl- and ethoxycarbonylmethylenethiotetrachloropyridines to the corresponding sulfones, while nitric acid gives a mixture of tetrachloropyridinesulfonic acid and the corresponding benzole acid. quantitative yields (Table 2).Translated from Khimiya Geterotsiklicheskikh Soedinenii,No.8, pp. 1094–1098, August, 1972.     

Crystal and molecular structure of 3β-acetoxy-22S,25-epoxyholosta-7,9(11)-dien-17α-ol

A complete x-ray structural investigation has been made of 3-acetoxy-22S,25-epoxyholosta-7,9(11)-dien-17-ol. Important conformational differences between this compound and its 17-deoxy derivative have been found which show the mobility of the conformation of rings B and C of the holostane series and the tetrahydrofuran ring of the side chain of the molecule. It has been shown that the conformation of the side chain of the molecule is stabilized by an 017-H...022 intramolecular hydrogen bond, without excluding the possibility of the participation of the hydroxy group in the formation of intermolecular hydrogen bonds (bifurcated).Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 341–344, May–August, 1992.     

Pyrimidine derivatives. 56. New method for the synthesis of thieno[2,3-d]pyrimidine

A new scheme was developed for the synthesis of 2,4-dimethy1-5,6-dihydro-6-bromomethylthieno[2,3-d]pyrimidine by bromination of the corresponding 5-allyl-6-mercaptopyrimidine. It is shown that when the bromomethyl derivative is treated with sodium methoxide a molecule of hydrogen bromide is split out to give 2,4,6-trimethylthieno[2,3-d]pyrimidine. The structures of the synthesized compounds were proved by PMR spectroscopy and mass spectrometry.See [1] for Communication 55.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 118–120, January, 1982.     

Cyclization of ethers of geraniol and nerol

Summary The cyclization of the ethers of geraniol and nerol under the influence of sulfuric acid or boron trifluoride leads to the formation of the-cyclo derivative, independent of the configuration of the 6,7-double bond in the acyclic molecule, i.e., it is not stereospecific.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1068–1070, June, 1965     

Pyrroloindoles. 5. Acetylation of 1H,6H-pyrrolo[2,3-e]indole by means of the Vilsmeier-Haack reaction

The Vilsmeier-Haack reaction with 1H,6H-pyrrolo[2,3-e]indole with the participation of dimethylacetamide was studied. 3-Acetyl, 8-acetyl, 2-acetyl, and 3,8-diacetyl derivatives (with great preponderance of the 3-acetyl derivative) were obtained. The formation of a 2-substituted product does not have an analogy in the chemistry of indole. On the basis of data from the IR and PMR spectra it was established that an intramolecular hydrogen bond between 1-H and the C=O group in the 8 position exists in the 8-acetylpyrroloindole molecule. This bond also affects the mass-spectral fragmentation of the 8-acetyl derivative.See [1] for communication 4.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 206–211, February, 1982.     

Use of near-infrared reflectance spectroscopy in predicting nitrogen,phosphorus and calcium contents in heterogeneous woody plant species

Near-infrared reflectance spectroscopy was applied to determine nitrogen (N), phosphorus (P) and calcium (Ca) content in leaf samples of 18 woody species. A total of 183 samples from mountain, riparian and dry areas from the Central–Western Iberian Peninsula were collected for this purpose. The wide intervals of variation observed in nutrient concentrations (6.6–45.0 g kg^–1 for N, 0.24–2.97 g kg^–1 for P, and 1.00–20.06 g kg^–1 for Ca) were due to the great heterogeneity of the samples. To develop calibration equations, multiple linear regression, and partial least-squares regression (PLSR) were used. In both cases, three mathematical transformations of the data were applied: log1/R and first and second derivatives. The best calibration statistics were obtained using PLSR and derivative transformations (second derivative for N and first derivative for P and Ca). The following coefficients of multiple determination (R²) and standard errors of cross validation were obtained: 0.99 and 0.93 for N, 0.94 and 0.15 for P, and 0.95 and 0.88 for Ca. In the external validation the standard errors of prediction obtained were 0.76 (N), 0.11 (P) and 0.60 (Ca).     

Reaction of phenylbenzoxazole with phenyl glycidyl ether

Conclusions The reaction of phenyibenzoxazole with phenyl glycidyl ether is not limited to the addition of the -oxide ring to the C=N bond of phenyibenzoxazole, but is followed by addition of a second molecule of phenyl glycidyl ether with the formation of an N derivative of hydroxyaniline.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1356–1359, June, 1987.     

Conformational analysis and vibrational spectroscopic investigation of 3-phenylpropylamine

The possible stable forms of 3-phenylpropylamine (3-PPA) molecule were experimentally and theoretically studied by infrared and Raman spectroscopy. FT-IR and Raman spectra of 3-PPA were recorded in the regions of 4000–400 cm⁻¹ and 3700–60 cm⁻¹, respectively. The potential energy surface corresponding to the internal rotations of the molecule was investigated by semi-empirical quantum mechanical methods, and appropriate conformers defined with B3LYP hybrid density functional theory method along with the basis sets of different size and type. Results from experimental and theoretical data showed the trans–trans–gauche (TTG) to be the most stable form of a 3-PPA molecule.     

Linear and Nonlinear Optical Properties of C60 Derivative Sol-Gels

Optical limiting properties of a sol-gel, functionalized with C₆₀ derivative molecule were studied by the nonlinear transmission technique in 480–650 nm wavelength range with nanosecond pulsed laser. The solid plates, with functionalized derivative C₆₀ concentration equal to 0.004 ML^–1, show interesting limiting behavior with threshold around 0.01 J/cm². The damage threshold ranges between 0.1 and 10 J/cm² depending upon the sample optical quality. The nonlinear optical properties of sol-gels were determined also by the optical third harmonic generation. At 1907 nm the cubic ⁽³⁾ (–3 ; , , ) susceptibility is of 1.3(± 0.1) × 10^–14 esu.     

Determination of some monoazo compounds by derivative pulse polarography

Summary The determination of some monoazo compounds by derivative pulse polarography has been investigated. The effect of pH is studied, and the optimum pH was determined to give the highest sensitivity. The detection limit is ca. 1×10^–5 M. Response is linear up to 8×10^–4 M.

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Bestimmung einiger Monoazoverbindungen durch derivative Pulspolarographie

Zusammenfassung Die Bestimmungsmöglichkeiten für einige Monoazoverbindungen durch derivative Pulspolarographie wurden untersucht. Der Einfluß des pH-Wertes wurde getestet und der jeweils optimale Wert in Abhängigkeit von den Substituenten ermittelt. Die Nachweisgrenze liegt bei 1×10^–5 M. Die Anzeige ist linear bis 8×10^–4 M.

     

Marked variations of proton release energy of the G–M (M = Li, Na) in the water circumstance

The variations of N1–H proton release energy of G–M (M = Li, Na) cation have been investigated employing density functional theory using B3LYP/6-31++G^**//B3LYP/6-31+G^* method. There are three modes (NO mode, N mode and O mode) when the hydrated-M⁺ bonds to guanine. The bonding energy of the hydrated M⁺ to the guanine reduces following the increase in the number of water molecules. The proton release energies of the G–M⁺ complexes are calculated at the condition of the different numbers of water molecules and the different modes of water molecules bonded on the G–M⁺. The results show that the difference of proton release energy on three modes is very small, and the proton release energies of the Na⁺ complexes are slightly larger than those of the Li⁺ complexes. The effect on the N1–H proton release is very small when the water molecules bond on the M⁺ cation, but the effect is very large when the water molecule bonds on the N1–H proton and the proton releases as the hydrated proton. The IR vibrational frequencies of the hydrated G–M⁺ complexes are calculated using analytic second derivative methods at the B3LYP/6-31+G^* level. The vibrational frequency analyses show that the changes of the vibrational frequency are consistent with the changes of geometry and the changes of the N1–H proton release energy. The N1–H proton release (N1–H proton release energy: 45–60 kcal/mol) of the guanine occurs easily under the biological environment.     

Free radicals in electrochemical reduction of 3,5-dicarbethoxy-1,4-dihydropyridines with nitrophenyl groups in positions 2, 4, and 6

In the electrochemical reduction of 2,6-bis- and 2,4,6-tris(nitrophenyl) derivatives of 3,5-dicarbethoxy-1,4-dihydropyridine, in the first stage, one of the para-nitrophenyl groups in position 2 or 6 of the heterocycle is reduced. Free radicals have been obtained and identified, the primary species being ion radicals of the nitrophenyl type. The presence of the heterocycle in the molecule of the 1,4-dihydropyridine derivative stabilizes secondary free radicals of the nitrosophenyl type. In the process of electrochemical reduction, no evidence has been found of any intramolecular transfer of electrons or protons from the dihydropyridine part of the molecule to the nitrophenyl groups. Derivatives of 2,6-bis(p-nitrophenyl)-3,5-dicarbethoxy-1,4-dihydropyridine have been synthesized, and the oxidation and methylation of these derivatives have been studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 481–487, April, 1991.