Alkaloids of Merendera iolantae

Summary The alkaloids ofMerendera iolantae E. Czerniak have been studied for the first time. The total alkaloids consist of tropolone compounds and bases without a tropolone ring. From this plant we isolated the known alkaloids colchicine, colchamine, -lumicolchicine, colchameine, and 2-demethylcolchiceine, and four new, nontropolone, bases — MI-1 (iolantamine), MI-2, MI-3, and MI-4. The presence of colchiceine, 3-demethylcolchamine, and two unknown bases with R _f 0.49 and 0.53 was shown by chromatographic methods.A developed formula has been put forward for iolantamine on the basis of its spectral characteristics.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 487–493, July–August, 1972.     

Alkaloids ofAconitum coreanum. I. Structure of acorine

Two C₂₀-diterpene alkaloids have been isolated from the epigeal part ofAconitum coreanum (Levl.) Rapaics: the known 14-hydroxy-2-isobutyrylhetesine (I) (Guan-Fu base Z) and a new one — acorine (II), C₂₂H₂₉NO₅, mp 214–215°C (from acetone), _D ²⁰ +9° (c 0.01; methanol), for which the structure of 2-acetyl-14-hydroxy-hetesine has been established. Details of the IR, mass, and¹³C NMR spectrum of (I) and (II) and of the PMR spectrum of (II) are given.Institute of the Chemisry of Plant Substances of the Uzbek Academy of Sciences, Tashkent. All Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedenenii, No. 5, pp. 690–692, September–October, 1987.     

Alkaloids ofPetilium raddeana. III. Structure of petisidinine

From a mixture of bases from the epigeal part and the bulbs ofPetilium raddeana (Rgl.) Vved. ex Pazij, a new base petisidinine has been isolated with mp 290–292°C (decomp.), composition C₂₇H₃₉NO₃ (I). On the basis of the physicochemical properties of the alkaloid and a correlation with petisine, the structure and configuration of petisidinine have been established as those of 3-hydroxy-20-(5-hydroxy-3-methylpyridin-6-yl)-5-pregnan-6-one.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Trashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 747–749, November–December, 1983.     

Stereoselective Synthesis of Enantiomerically Pure Nupharamine Alkaloids from Castoreum

An animalic note : The first total synthesis of the all‐cis nupharamine 2 , an alkaloid from beaver castoreum, is based on the stereoselective domino Mannich–Michael reaction of N‐galactosylfurylaldimine to give 1 (Piv=pivaloyl), subsequent conjugate cuprate addition, and stereoselective protonation of the enolate. These reactions are all controlled by the carbohydrate. Protonation of the enolate after cleavage of the auxiliary leads to epimer 3 .

     

Alkaloids ofHaplophyllum dauricum

From the roots ofHaplophyllum dauricum (L) G. Don., collected on the territory of the Uvur-Khangai aimak, Mongolian People's Republic, in the fruit-bearing stage have been isolated robustine, dictamnine, -fagarine, haplopine, skimmianine, 4-methoxy-N-methyl-2-quinolone, folimine, robustinine, and the new alkaloid daurine the structure of which has been established as 8-(,-dimethylallyloxy)-4-methoxy-N-methyl-2-quinolone.Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 73–76, January–February, 1984.     

Studies on the Alkaloids of Lotus Receptacle

From lotus receptacle (seed pod of Nelumbo nucifera Gaertn., four alkaloids, nuciferine (I), N-nornuciferine (VIII), oxoushinsunine (IX) and N-norarmepavine (X) were isolated. Identification of these bases were carried out by their spectral data and direct comparison with authentic samples. It is interesting that oxoushinsunine (IX), a cytotoxic alkaloid shows tumor inhibitory activity against nasopharynx carcinoma reported recently by D. Warthen et al¹³⁾. The biscoclaurine (IV and V) and quaternary water soluble base (VI) only occures in the embryo. Comparison their alkaloids distribution in each part of Formosan lotus was listed in the Table 1.     

An efficient synthesis of new benzo[1′,2′:6,7]quinolino[2,3‐d]‐pyrimidine derivatives via three‐component microwave‐assisted reaction

A series of benzo[1′,2′:6,7]quinolino[2,3‐d]pyrimidine derivatives were synthesized via condensation of an aromatic aldehyde, 2‐hydroxy naphthalene‐1,4‐dione and 2,6‐diaminopyrimidin‐4‐one in mixed solvent of acetic acid and glycol (3:1,V:V) under microwave irradiation. This one‐pot protocol has the advantage of good yield (86‐91%), simple workup procedure and rapid reaction time (4‐8min).     

Isomerization of the Radical Anions of 6a-Thiathiophthenes

The radical anions of 6a-thiathiophthenes ([1,2]dithiolo[1,5-b] [1,2]dithioles), I(R), convert into those of 4H-thiapyran-4-thiones, III(R), via cis-trans isomerization. The reaction is slowed down when the size of the substituent R in the 2,5-positions of 6a-thiathiophthene increases, and it is prevented by the introduction of a 3,4-polymethylene bridge. The primary and the secondary radical anions, I(R)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document} and III(R)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, respectively, exhibit very similar hyperfine splitting patterns. E.g., in the case of the unsubstituted 6a-thiathiophthene, I(H), and 4H-thiapyran-4-thione, III(H), the proton coupling constants are a_H2,5=6.72 and a_H3,4=1.73 Gauss for I(H)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, and a_H2,6=6.35 and a_H3,5=2.07 Gauss for III(H)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}. In contrast to I(H)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, cis-trans isomerization could not thus far be proved to occur with its 1,6-dioxa-analogue, IV(H)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, since no ESR. spectrum of the radical anion of 4H-pyran-4-thione, V(H), was detected upon reduction of IV(H).     

Alkaloids of Stephania hernandifolia VI. Hernandifoline

Summary A new hasubanan alkaloid with the composition C₂₉H₃₃O₉N, mp 128–129°C₉ from ether), [] _D ²⁰ – 25° (c 2; ethanol) containing an ester group has been isolated from the herbStephania hernandifolia and has been called hernandifoline.All-Union Scientific-Research Institute for Medicinal Plants. Translated from Khimiya Prirodynkh Soedinenii, No. 2, pp. 158–164, March, 1971.     

Investigation in the field of pyrimidines

The alkylation of 2-amino-4-methyl-6-oxopyrimidine and 2-amino-6-chloro-4-methylpyrimidine with acrylonitrile in an aqueous alkaline medium takes place at the ring nitrogen with the formation of 2-amino-1-(-carboxyethyl)-4-methyl-6-oxopyrimidine (I). A number of esters of compound I have been obtained in the form of hydrochlorides.     

Variants of the complete synthesis of d,l-19-nortestosterone, d,l-19-norandrost-4-ene-3, 17-dione, and their stereoisomers

Summary The complete synthesis of d,l-19-nortestosterone (I) and its 8-iso- and 9, 10-iso- stereoisomers, and also the synthesis of d,l-19-norandrosten-4-ene-3, 17-dione (VI) and its 9, 10-iso-stereoisomer (IX), has been carried out.The stereodirectivity of the simultaneous reduction of the ⁸⁽⁹⁾ double bond and the aromatic ring conjugated with it by means of alkali metals and alcohol in liquid ammonia, both under Birch's conditions and Wilds and Nelson's conditions, depends on the nature of the substituent at C₁₇; in the case of the 17-ketone (III) and the carbinol (VIII), considerable amounts of the 9- isomers are formed.Compounds (I), (Ia), (Ib), (V), and (VI) possess anabolic activity, but to a smaller extent than the analogous compounds in the d,l-D-homo series.Khimiya Prirodnykh Soedinenii, Vol. 1, No. 3, pp. 180–188, 1965     

Kinetics of reversible recombination of aromatic C-centered radicals

The kinetics of the reversible recombination of the 2-phenyl- (I), 2-p-methoxyphenyl-(II), and 2-p-nitrophenyl-3-oxo-2,3-dihydrobenzothiophene-2-yl (III) radicals have been investigated. Recombination rate constants of R(I–III) have been determined in different solvents (2k₁ ～ 10⁹ M^?1 s^?1). The rate of reaction (I) with R(I–III) decreases with increasing solvent viscosity η. In the toluene-vaseline oil mixture (2 ? η ? 120 cP) the recombination of R(I–III) is molecular mobility limited. The thermodynamic parameters of reaction (I) have been determined: ΔH⁰ = 20–30 kcal/mol. Activation volumes ΔV for recombination of R(II) have been measured. In n-propanol ΔV is equal to the viscous flow activation volume of the solvent ΔV. In toluene and chloroform ΔV < ΔV. For the last two solvents the activation volumes of the cage reaction have been estimated ΔV = ?(2–3) cm³/mol. Visible-range absorption spectra and ESR spectra have been recorded for R(I–III). The role of cage effect in the reactivity anisotropy averaging of R(I–III) is discussed. The potential of the high-pressure tests for deriving information about the elementary act of a fast bimolecular reaction is considered.     

Solvent effect on reversible self-termination reactions of aromatic free radicals

Rates and thermodynamic data have been obtained for the reversible self-termination reaction: Involving aromatic 2-(4′dimethylaminophenyl)indandione-1,3-yl (I), 2-(4′diphenylaminophenyl)indandione-1,3-yl (II), and 2,6 di-tert-butyl-4-(β-phthalylvinyl)-phenoxyl (III) radicals in different solvents. The type of solvent does not tangibly affect the 2k₁ of Radical(I), obviously due to a compensation effect. The log(2k₁) versus solvent parameter E_T(30) curves for the recombination of radicals (II) and (III) have been found to be V shaped, the minimum corresponding to chloroform. The intensive solvation of Radical (II) by chloroform converts the initially diffusion-controlled recombination of the radical into an activated reaction. The log (2k_?1) of the dimer of Radical (I) has been found to be a linear function of the Kirkwood parameter (ε - 1)/(2ε + 1), the dissociation rate increasing with the dielectic constant of the solvent. The investigation revealed an isokinetic relationship for the decay of the dimer of Radical (I), an isokinetic temperature β = 408 K and isoequilibrium relationship for the reversible recombination of Radical (I) with β° = 651 K. For Radical (I) dimer decay In(2k_?1) = const + 0.8 In K, where K is the equilibrium constant of this reversible reaction. The transition state of Radical (I) dimer dissociation reaction looks more like a pair of radicals than the initial dimer. The role of specific solvation in radical self-termination reactions is discussed.     

Alkaloids ofRhinopetalum bucharicum. The structure of rhinolinine

The combined alkaloids of the epigeal part ofRhinopetalum bucharicum have yielded solanidine, rhinoline, imperialine, a base with mp 272–274°C, and the new alkaloid rhinolinine with mp 301–302°C (methanol), []_D — 36.5° (c 1.7, ethanol), C₄₀H₆₇NO₁₂. On the basis of a study of IR and NMR spectra, and also passage to the known alkaloids rhinoline and rhinolidine, the structure of rhinolidine 3-O-[O--D-glucopyranosyl-(14)--D-glucopyranoside] has been established for rhinolinine.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 350–353, May–June, 1979.     

Novel Copolymers Based Tetrafluorobenzene and Difluorobenzothiadiazole for Organic Solar Cells with Prominent Open Circuit Voltage and Stability

Two novel copolymers based on benzothiadiazole (BT) or difluorobenzothiadizole (ffBT) with 2,2′‐(perfluoro‐1,4‐phenylene)dithiophene (2TPF4), namely PBT‐2TPF4 and PffBT‐2TPF4, are synthesized for applications in polymer solar cells (PSCs). A noticeably high open‐circuit voltage (V _oc) of 1.017 and 0.87 V are achieved for PffBT‐2TPF4 and PBT‐2TPF4‐based devices, respectively. Although only a moderate efficiency (5.7%) of PBT‐2TPF4‐based devices is obtained, it is first demonstrated that 2TPF4 is a promising acceptor block for construction of the donor copolymers which possess high V _oc, prominent crystallinity, and long‐term stability, simultaneously. Besides, two thienyl flanking the tetrafluorophenylene can decrease torsion angle between conjugated units, resulting in a high coplanar structure of copolymers to enhance their charge carrier mobility. The findings may open a promising and practical way to accelerate the commercialization of PSCs by developing a series of new donor copolymers for efficient and long‐term stable thickness bulk heterojunction PSCs.

     

Alkaloids ofPetilium raddeana II. Structures of petisine and petisinine

The alkaloids imperialine, imperialone, peumisine, petiline, petilidine, and the new bases petisine (I) and petisinine (III) have been isolated from bulbs ofPetilium raddeana (Regl.) Vved. On the basis of spectral characteristics and passages to a known compound, the structure of 3-hydroxy-²²(N)-22,26-iminocholestane-6,23-dione has been established for (I) and petisine 3-glucopyranoside for (III).Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 616–619, September–October, 1981.     

Theoretical determination of absolute free energy of reduction of plastoquinone-9 in photosystem II and of plastoquinone-n in DMF

We employed static continuum electrostatics and multi-conformation continuum electrostatics (MCCE) methods to determine the reduction potential () of PQ-9 in a section of Photosystem II (PSII). Both methods relied on the finite difference Poisson–Boltzmann (FDPB) solution. The static method brings out a value (0.01 V) that is close to the experimental one (0.05 V), thereby demonstrating that the surrounding environment critically decides the net free energy change. The value obtained from MCCE (0.04 V) is even closer to the observed value, thereby indicating the importance of protein side-chain and proton motions in the electron transfer process. Furthermore, density functional theory-dielectric polarisable continuum model (DFT-DPCM) was employed to calculate the absolute free energy of reduction of plastoquinone-n (PQ-n, where n is the number of isoprenoid units) in N,N dimethyl formamide (DMF) solvent. The DFT-DPCM method produced reduction potential values of −0.59 and −0.65 V for PQ-1 and PQ-9, respectively. These are more or less in agreement with the experimentally reported values of −0.64 and −0.62 V, respectively.     

Triterpenoids from the leaves of far eastern species of the shrubby birchesBetula ovalifolia andB. middendorfii

From the unsaponifiable fraction of an ethereal extract of the leaves ofBetula ovalifolia have been isolated the new triterpene 20(S),24(R)-epoxydammarane-3,17,25-triol (V) and the corresponding monoketone at C³ (VI). The leaves ofB. middendorfii have yielded the triterpene (IX) and (X), identified as, respectively, dammar-23-ene-3,12,20(S),25-tetraol and damman-25-ene-3,12,20-(S),24-tetraol, which have been obtained previously from the leaves ofBetula platyphylla Sukatchev var.japonica.The species of birch were determined by V. I. Baranov of the Laboratory of Chemotaxonomy.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 323–329, May–June, 1981.     

Syntheses of oxazolo[4,5‐c]pyridine and 6‐azaindole

The preparation of oxazolo[4,5‐c]pyridine and 6‐azaindole from 4‐bromo‐3‐pivaloylaminopyridine ( 8 ) is reported. The oxazolopyridine 2‐tert‐butyl‐oxazolo[4,5‐c]pyridine ( 9 ) was successfully prepared from 8 in 78% yield by a new base/TBAB promoted non‐catalyzed microwave cyclisation strategy (10 min) or, alternatively, in 54% yield by conventional heating (48 hrs) and CuI catalysis. The 6‐azaindole 2‐phenyl‐1‐(trimethylacetyl)‐6‐azaindole ( 13 ) was prepared from 8 in a two step procedure, including a Sonogashira coupling reaction.