Synthesis of bridged isoflavone derivatives

Summary 7-Chloroalkoxyisoflavones (10–26) have been prepared by chemoselective-in the case of 5,7-dihydroxyisoflavones also regioselective-alkylation of hydroxyisoflavones (3–9) with -bromo--chloroalkanes. Compounds10–26 were allowed to react either with 2,4-dihydroxy-3-n-propylacetophenone (1) or with 2-ethoxycarbonyl-7-hydroxy-8-n-propylchromone (2) to afford bridged isoflavone derivatives27–51 with methylene spacers of various length. Carboxylic acid ethyl esters43–51 have been saponified to obtain the carboxylic acids52–60.

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Darstellung überbrückter Isoflavonderivate

Zusammenfassung Die chemoselektive und bei den 5,7-Dihydroxyisoflavonen auch regioselektive Alkylierung von Hydroxyisoflavonen3 bis9 mit -Brom--chloralkanen ergibt 7-Chloralkoxyisoflavone10 bis26. Die Umsetzung des 2,4-Dihydroxy-3-n-propylacetophenons und 2-Ethoxycarbonyl-7-hydroxy-8-n-propylchromons mit den Verbindungen10 bis26 liefert die überbrückten Isoflavone27 bis51 mit einem Methylen-Spacer verschiedener Länge. Die Verseifung der Ester43 bis51 führt zu den Carbonsäuren52 bis60.

     

Synthesis of an analogue of the phospholipid platelet activation factor from a natural ethanolamine plasmalogen

The synthesis has been performed of an analogue of the phospholipid platelet activation factor — 1-0-(alk-1-enyl)-2-acetyl-sn-glycero-3-phospho-N-(N-acetylglycylethanolamine). In concentrations of 10^–7-10^–6 M, the analogues so obtained inhibited the aggregation of human platelets stimulated by the phospholipid activation factor.Scientific-Research Institute of Biomedical Technology, USSR Ministry of Health, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 325–330, May–June, 1990.     

Spirocyclic betaines or 2-amino-Δ2-1,3,4-thiadiazoline-5-acetic acid and their rearrangement in acetic anhydride

Reaction of N-(1-pyrrolidinyl)-, N-(1-piperidinyl)-, N-(4-morpholinyl)-, and N-(1-hexahydroazepinyl)-thioureas with propiolic acid gives hetero-N-spiro-4-(2-amino-²-1,3,4-thiadizolin-4-io-5-acetates), which rearrange in acetic anhydride to 2-(N-heteryl)imino-2,3-dihydro-4H-1,3-thiazin-4-ones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 263–265, February, 1993.     

Kinetics and mechanism of decarboxylation of cis-carbonato- and bicarbonato(3,3′,3′′-triaminotripropylamine)cobalt(III) ions

The acid-catalysed hydrolysis of [Co(trpn)(CO3)]+ and [Co(trpn)(HCO3)]2+ ions (trpn = 3,3,3-triaminotripropylamine) have been studied spectrophotometrically in aqueous 1.0m HClO4/NaClO4. For the carbonato complex, [HClO4] = 0.02–0.25m and T = 20–35°C; for the bicarbonato complex, [HClO4] = 0.025–0.30m and T = 25°C. Both complexes hydrolyse to form the same cis-diaqua species. The rate law for the hydrolysis is d(ln[CoIII])/dt = k0+k1[H3O+]. The values of the rate constants (25°C), H (kJmol–1) and S (Jmol–1K–1)are:[Co(trpn)(CO3)]+,k0 = (1.7±0.6)× 10–4s–1, H 0 = 57±21, S 0 = –126±75; k1 = (1.0 ±0.1)×10–2m–1s–1, HDagger;1 = 62±8, S1 = –75 ±21, and for [Co(trpn)(HCO3)]2+, k0 = (2.9±0.7)× 10–4s–1, and k1 = (7.8±1.0)×10–2m–1s–1. The carbonato complex exhibits a deuterium isotope effect with k1D/k1H = 1.9, consistent with a rapid pre-equilibrium protonation, followed by rate-controlling ring-opening. The rate constants k0 and k1 (25°C and = 1.0m) for the ring-opening decarboxylation of the two systems studied lie within the experimental error. The results are compared with o ther related systems and the factors which influence the ring-opening decarboxylation (steric hindrance, ring strain, electron-donor ability of the amines) are discussed. The k1 path is interpreted in terms of concerted ring-opening and bond-making in the highly unstable aquabicarbonato intermediate.     

Applications of Laser-Raman spectroscopy to the analysis of polynucleotides containing uridine residues

Summary Qualitative characterization of uridine C(2)-endo-anti and C(3)-endo-anti forms has been carried out for the first time using Laser-Raman spectroscopy. Spectra are presented for some crystals containing the uridine residue whose conformations are known from their X-ray crystallographic analyses. Crystalline uridine and uridine 5-monophosphate as its lithium, sodium, potassium, barium and cadmium salts give Raman bands in the 600–700 cm^–1 range that seem to reflect sensitively and regularly the conformation of the uridine residue and, therefore, are proposed as convenient indicators of the above structures. A method for the determination of the uridine C(2)-endo-anti form in polyribonucleotides is also described. The usefulness of these characterizations in the conformational analysis of polyribonucleotides is shown.     

Imidazoline ring cleavage in 1,3,6,10-tetraazatetracyclo-[7.3.1.02,7.06,13]trideca-4, 11-dienes,leading to the formation of diquinoxalino[1,2-a∶2′,3′-d]pyrrole derivatives

Dibenzo[d,k]-1,3,6,10-tetraazatetracyclo[7.3.1.0^2,7.0^6,13]trideca-4,11-dienes undergo addition reactions at the C₍₂₎ carbon atom with alcohols and thiols, accompanied by cleavage of the C-N bond of the imidazoline ring, to generate diquinoxalino[1,2-a2,3-d]pyrrole derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 513–522, April, 1987.     

Room temperature phosphorescence optosensing for gadolinium

An optosensing method for gadolinium based on the room-temperature phosphorescence behavior in aqueous solution induced by the transient adsorption of the complex formed by 1,4-bis (1-phenyl-3-methyl-5-pyrazolone-4-)butanedione (1,4) with Gd (III) on the chelating resin Chelex 100 (packed in a flow cell) is proposed. The proposed optosensing is satisfactory for the determination of the gadolinium ion in the range 8 × 10^–7–5 × 10^–5 M with a correlation coefficient of 0.995. The relative standard deviation was 2.0% for determination of 5× 10^–6 M gadolinium ion (n = 10). The response mechanism of the optosensing and the interferences of other lanthanide ions were also investigated. The method has been used to determine gadolinium ion in synthetic sample.     

Behavior of14C-DDE in the soil of subtropical conditions

The behaviour of p,p-DDE in upland and flooded soil conditions was studied by using¹⁴C-p,p-DDE in Hangzhou, China. The dissipation speed of¹⁴C-DDE from upland soil is faster than that from flooded soil, especially in the second phase. In flooded soil, 0–8 week T_1/2=3.42 (methanol extractable); 8–43 week, T_1/2=10.10; in uplan soil, 0–8 week, T_1/2=3.22; 8–43 week, T_1/2=7.22. There is not too much difference in the distribution patten between upland and flooded soil. Most of the¹⁴C-residue is within 2 cm layer of soil column. DDE is very stable in both upland and flooded soil conditions. Experiments were carried out under natural conditions in a net house. LSC (Pachard 1900TR) was used for¹⁴C-counting. TLC technique^[4] was engaged for the analyzing of its degradation products.     

Reaction of 2-methyl-4,5-dihydrofuran with hydrogen chloride

Reaction of 2-methyl-4,5-dihydrofuran with HCl at 0°C yields 5-chloro-2-pentanone (13%) and 1-(2-methyltetrahydrofuryl-2)-5-chloro-2-pentanone (27%) and at 200° 5-chloro-2-pentanone exclusively.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. I. M. Gubkin State Petroleum and Gas Academy, 117917 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2188–2191, September, 1992.     

Synthesis of new unsaturated mesotetraarylporphyrins

A method has been developed for the preparation of tetra(4-vinylphenyl)porphyrin by the condensation of 4--halogenethylbenzaldehyde with pyrrole and dehydrohalogenation of the obtained tetra(4-halogenethylphenyl) porphyrins.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 221–226, February, 1987.     

Spectrophotometric determination of quercetin with VO2+

Summary The coloured complex formed on reaction of quercetin (3,3, 4, 5,7-pentahydroxyflavone) with vanadyl sulphate is used as the basis for a sensitive and reproducible spectrophotometric method for estimation of quercetin. The 11 complex exhibits maximum absorption at 425 nm in aqueous ethanol (80% v/v) adjusted to pH 3.3. Beer's law is followed over the quercetin concentration range of 0.3–20 g/ml. The molar absorptivity is 1.4×10⁴ l·mole^–1·cm^–1. This method can be used for the determination of quercetin isolated from biological sources. In the metal complex, the 4-carbonyl and 3-hydroxy groups of the quercetin are involved.

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Zusammenfassung Der bei der Umsetzung von Quercetin (3,3, 4, 5,7-Pentahydroxyflavon) mit Vanadylsulfat entstehende gefärbte Komplex wurde als Grundlage für eine empfindliche und reproduzierbare spektrophotometrische Bestimmung von Quercetin verwendet. Die maximale Absorption dieses 11-Komplexes beträgt in wäßrigem Äthanol (80% v/v) bei pH 3,3 und 425 nm. Bei Quercetin-Konzentrationen zwischen 0,3 und 20 g/ml gilt das Beersche Gesetz. Der molare Extinktionskoeffizient beträgt 1,4·10⁴ l· mol^–1·cm^–1. Das Verfahren kann zur Quercetinbestimmung nach Isolierung aus biologischem Material verwendet werden. An der Komplexbildung ist die 4-Carbonyl- und die 3-Hydroxygruppe des Quercetins beteiligt.

     

Molecular Association and Solvent Effects in the Electronic and NMR Spectra of the Tricyanoterpyridineruthenate(II) Complex

Solvent effects on the electronic structure and NMR spectra of the[Ru(terpy)(CN)₃] complex(terpy = 2,2,6,2-terpyridine) have beeninvestigated and interpreted using quantum mechanical semiempirical methods.A systematic splitting of the electronic bands in the visible is observed, in addition to theirbathochromic shifts depending on the acceptor number of the solvent. The solvent-inducedsplittings are rationalized in terms of the involvement of several charge—transfertransitions exhibiting distinct participation of the ruthenium (II), terpy, and CN^–orbitals. Direct evidence of solvent interaction at the cyanide ligands is observedin the [¹³C]NMR spectra. The most enhanced solvent effects are at the middle¹³C-4 and ¹H-4 atoms of terpy, in complete agreement with the theoreticalcalculations. In D₂O, stacking interactions involving the terpy ligands are detectedfrom the [¹H]NMR spectra, leading to a bimolecular association constant of90 mol^–1-dm³. In acetone—D₂O mixed solvents, the spectroscopic changes areindicative of preferential solvation departing from the ideal linear behavior.     

Homo- and heterodinuclear 2,2′-bipyrimidine-bridged complexes

[M(hfacac)₂(bpym)] complexes, where M = Co^II, Ni^II or Zn^II, hfacac = hexafluoroacetylacetonate and bpym = 2,2bipyrimidine; and [Cl₂M(bpym)M(hfacac)₂] complexes, where M = Co^II, Ni^II Mn^II or ZnII M = Ni^II; M = NiII or Zn^II and M = Zn^II; M = Ni^II and M = Co^II have been prepared and characterized by chemical analysis, conductance measurements, IR and electronic spectroscopies and magnetic susceptibility measurements (4.2–292K range). The dinuclear NiII–Ni^II, Co^II–Ni^II and Mn^II–Ni^II complexes are antiferromagnetic, with an intramolecular exchange parameter, J, of –2.3–8.9cm–1. Co^II and Mn^II are in a high spin state. The low temperature effect observed in monomers and in Ni^II–Zn^II dimers is considered a consequence of either an intermolecular antiferromagnetic interaction or the zero-field splitting in NiII.     

Subshell-pair interelectronic angles of atoms in momentum space

Average angles between linear momenta of an electron in a subshell nl and another electron in a subshell nl are examined for the 102 atoms He through Lr in their ground states, where n and l are the principal and azimuthal quantum numbers, respectively. Congruency in the mathematical structures of the average interelectronic angles in position and momentum spaces leads to the theoretical results that with even |l–l| are exactly equal to 90°, while with odd |l–l| are always larger than 90°. Numerical analyses of 3,275 subshell-pair angles with odd |l–l| in the 102 atoms clarify that deviations of the total average interelectronic angles from 90° are mainly governed by subshell pairs with |n–n|1 and |l–l|=1, in contrast to the position-space results where only subshell pairs with n=n and |l–l|=1 are important.Acknowledgments. We thank Mr. T. Shimazaki for his assistance in the compilation of data. This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education of Japan.     

Reactions of pennogenin and related compounds. IV. Formation of (25R,22′R,25′R)-3β,3′β-diacetoxy-26,22′-epoxy-16,16′-bifurosta-5,20(22),5′,17′(20′)-tetraen-26′-ol from pennogenin diacetate under the action of BF3·Et2O

A new direction of the reaction of pennogenin diacetate with BF₃·Et₂O has been discovered in which a previously unknown dimeric steroid is formed — (25R,22R,25R)-3,3-diacetoxy-26,22-epoxy-16,16-bifurosta-5,20(22), 5,17(20)-tetraen-26-ol, the structure of which has been established as the result of an analysis of IR, UV,¹H and¹³C NMR, and mass spectra. A probable mechanism for the formation of the title compound from pennogenin diacetate is suggested.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, USSR Academy of Sciences, Vladivostok. Institute of Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 202–208, March–April, 1990.     

Structure of photochromic 1′-phenyl-3′,3′-dimethyl-11-nitrospiro (indoline-2,2′-[2H-1]naphthopyran)

Conclusions X-ray diffraction structural analysis was used to establish the structure of photochromic r-phenyl-3,3-dimethyl-11-nitrospiro (indoline-2,2-[2H-1]-naphthopyran) and showed that the (5-6)-fusion of an additional benzene ring in the spiropyran, in which an NO₂ group is located at C¹¹, leads to shortening of the C_spiro-0 bond to 1.460(2) å in comparison to an unfused analog, although this bond is longer than an ordinary C-O bond in six-membered heterocycles.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 188–190, January, 1987.     

Kinetics and mechanism of nucleophilic substitution of dichloro{1-methyl-2-(arylazo)imidazole}palladium(II) by pyridine bases

The reaction of dichloro{1-methyl-2-(arylazo)imidazole}palladium(II), Pd(RaaiMe)Cl₂ where RaaiMe = p-R–C₆H₄N=N–C₃H₂N₂-1-Me; R = H(1), Me(2), Cl(3), with pyridine bases [RPY: R = H (a), 4-Me (b), 4-Cl (c), 2-Me (d), 2,6-Me₂ (e), 2,4,6-Me₃ (f)] has been studied spectrophotometrically in MeCN at 451 nm. The products (4) have been isolated and characterised as trans-Pd(RPy)₂Cl₂. The kinetics of the nucleophilic substitution has been examined under pseudo-first-order conditions at 298 K. A single phase reaction step has been observed for bases such as Hpy (a), 4-MePy (b) and 4-ClPy (c) and follows the rate law: rate = (a + k[RPy]²[Pd(RaaiMe)Cl₂]). The bases 2-MePy (d), 2,6-Me₂Py (e) and 2,4,6-Me₃Py (f) exhibits a bi-phasic reaction and follows the rate laws: rate–1 = (a + k[RPy][Pd(RaaiMe)Cl₂]) and rate–2 = (a + k[RPy][Pd(RaaiMe)-Cl₂]), where k is the third-order rate constant; k is the second-order first phase rate constant, k is the second-order second phase rate constant and a/a/a correspond to the solvent dependent constant of the respective reaction path. The rate data supports a nucleophilic association path. External addition of Cl^– (LiCl) suppresses the rate, which follows the order: k/k/k (3) > k/k,k (1) > k/k,k (2). The k values are linearly related to the Hammett constants. The 2-substituted pyridines (d–f) remarkably reduce the rate and show a bi-phasic reaction behaviour as compared with 4-Rpy (a–c). This is attributed to the steric effect that destabilises the transition state. The rate decreases with increasing steric crowding at the ortho-position and follows the order: (d) > (f) > (e). The 4-substituted pyridines control the rate via an inductive effect and follow the order: (b) > (a) > (c).     

Preparation of DNA duplexes containing 2′-fluoro-2′-deoxyuridine and arabinosyluracil

The synthesis of two 14-membered duplexes containing 2-fluoro-2-deoxyuridine and 1--D-arabinosyluracil, respectively., has been effected by chemical ligation (CL). During the synthesis of the first of them, it was observed that the ammonolysis of the completely blocked ACGGAU^2F was accompanied by the transformation of the modified unit into arabinouridine with the formation of 45% of ACGGAU^ara. It has been established that the introduction of an electron-accepting substituent adjacent to the reacting 3-OH group has no influence on a characteristic feature established previously: CL is considerably more effective if the reacting phosphate group is present at the 3-end, and not the 5-end, of the oligonucleotide.M. V. Lomonosov Moscow State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 263–267, March–April, 1991.     

Benzylidene derivatives of 2-substituted 4.5; 1′,2′-glyco-Δ2-oxazolines

Conclusions A convenient method of obtaining partially substituted 2-desoxy-2-amino sugars with a free hydroxyl group at C₃ has been developed using the synthesis of benzylidene derivatives of 2-methyl-(or phenyl)-4,5; 12-glyco-²-oxazolines as examples.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2655–2657, November, 1968.