1,4,4a,10b-Tetrahydro-N,N-dimethyl-4-phenanthridinamines and 1,4,4a,5,6,10b-hexahydro-N,N-dimethyl-4-phenanthridinamines

Synthetic procedures to prepare the title compounds are described. Diels-Alder cycloaddition of β-nitrostyrene derivatives 5 to N,N-dimethyl-1,3-butadien-1-amine, 6 , gave 5-aryl-N,N-dimethyl-6-nitro-2-cyclohexen-1-amines 7. Reduction of 7 with zinc in acetic acid gave the diamino derivatives 8 . Schotten-Baumann acylation of 8 gave amides 9 . Treatment of 8 with alkyl isocyanates gave the aminourea derivatives 10 . Bischler-Napieralski cyclodehydration procudure of 9 and 10 gave 1,4,4a,10b-tetrahydrophenanthridinamines 3 and N⁶-alkyl-1,4,4a,10b-tetrahydro-N⁴,N⁴-dimethyl-4,6-phenanthridinediamines 11 , respectively. Condensation of diamines 8 with aryl aldehydes under azeotropic conditions gave imines 12 which on treatment with acids yielded 6-aryl-1,4,4a,5,6,10b-hexahydro-N,N-dimethyl-4-phenanthridinamines 4 . The stereochemistry of these materials is assigned from the proton magnetic resonance studies.     

Synthesis of 3, 4, 4a, 5, 6, 7, 8, 8a α-Octahydro-4a β, 8α-Dimethyl-2(1H)-Naphthalenones from the Wieland-Miescher Ketone

Conversion of the Wieland-Miescher ketone to a bicyclic dienophile capable of providing the AB rings of the picrasane skeleton of the guassinoids required the introduction of a C-8α methyl group in a 2-decalone. Among the routes explored, the conversion of the Wieland-Miescher ketone to a 4,4a,5,6,7,8-hexahydro-4aβ-methyl-8-methylene-2(3H)-napthalenone and subsequent reduction to a 3,4,4a,5,6,7,8,8aα-octahydro-4aβ,8α-dimethyl-2(1H)-napthalenone proved most useful.     

Crystal Structure of 3-methyl-1, 2, 3, 4, 4a, 4b, 9a, 15, 15a,15b-decahydro-(4,5);(4a,15)-dimethano-tricyclo(4, 3, 1, 0~(2,7)) deca 〔8, 9, 1, 10-a,b, c〕pyrido〔4,3-a〕-acridin-6-en-9-ol-8-one

1INTRODUCTIONIntheO-demethyIationof7a-o-amino-phenyl-6,14-endo-ethenotetrahydrothe-baine,catalyzedbyhydrobromicacid,ifinhightemperatureandprolongedtime,anewcomPoundwithyie1dof17.9%wasfound,whosestructurecannotbedeferredfromthepreviousacid-catalyzedrearrangementof6,14-endo-ethnotetrahydrothe-baines(1-33.ItwascrystallizedfromanhydrousethanolsolutionanditsstructurewasdeterminedbyX-raycrystallography.2EXPERmENTALAcrystalwithdimensionsofO.3mmXO.4mmXO.5mmwasmountedonanEnraf-NoniusCAD4d…     

Relativistic all-electron molecular Hartree-Fock-Dirac-(Breit) calculations on CH4, SiH4, GeH4, SnH4, PbH4

Summary Results and details of molecular Fock-Dirac-(Breit) calculations on CH₄, SiH₄, GeH₄, SnH₄, and PbH₄ obtained with the MOLFDIR© program package are presented and compared with other calculations and experimental results. The relativistic ground state energies (including the Breit interaction) of the atoms C, Si, Ge, Sn, and Pb, necessary for reference purposes, have been calculated using a small relativistic CI. One of our findings is that for the heavier systems perturbation theory over-estimates the relativistic bond length contraction. The Breit interaction has only a small effect on the bond lengths.     

4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene as a bright fluorescent label for DNA

4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) as a fluorescent label can be incorporated into DNA by two conceptually different ways: the non-nucleosidic DNA base surrogate Bo exhibits high brightness but no preferential base-pairing properties, whereas the BODIPY-modified uridine BodU has reduced quantum yields but shows preferred Watson-Crick base pairing with adenine.     

2, 4-bis(4-methoxyphenyl)-1, 3, 2, 4-dithiadiphosphetane 2, 4-disulfide,lr, as a new activation reagent in preparation of peptides,amides and esters

Abstract

2, 4-Bis(4-methoxyphenyl)-1, 3, 2, 4-dithiadiphosphetane 2, 4-disulfide, LR, is easily prepared by refluxing P₄S₁₀ in anisole for two hours produces the title compound in high yield.     

Synthesis,Crystal Structure and Anti-tumor Activity of 2-（2-Chloro-4-nitrophenyl）-4- （4-chlorophenyl）-3a,4-diethoxy-2,3,3a, 4-tetrahydrochromeno[3,4-d] [ 1,2,3]diazaphosphole

The title compound 2-（2-chloro-4-nitrophenyl）-4-（4-chlorophenyl）-3a,4- diethoxy- 2,3,3a, 4-tetrahydrochromeno[3,4-d][1,2,3]diazaphosphole 2 （C29H30Cl2N3O7P, Mr = 633.44） was synthesized and its structure was characterized by IR, MS, ^1H NMR, ^13C NMR, ^31p NMR, elemental analysis and single-crystal X-ray diffraction. It crystallizes in triclinic, space group P1^-, a = 9.1549（3）, b = 10.7168（4）, c = 17.6272（6）A, α = 102.9363（12）, β = 90.2713（9）, γ = 117.4265（10）°, V= 1484.41（9）A^3, Z= 2,μ（MoKa） = 0.323, F（000） = 658, Z= 2, De= 1.417 g/cm^3, the final R = 0.0687 and wR = 0.2066 for 4943 observed reflections （I 〉 2σ（I））. X-ray analysis reveals that the diazaphospholine ring is almost planar and the two ethoxy groups bonded on the 3a- and 4-positions are in trans configurations. Its antiproliferative activity was also tested in vitro against four human tumor cell lines.     

Water activity,osmotic and activity coefficients of aqueous solutions of Li2SO4, Na2SO4, K2SO4, (NH4)2SO4, MgSO4, MnSO4, NiSO4, CuSO4, and ZnSO4 at T=298.15 K

The water activities for aqueous solutions of Li₂SO₄(aq), Na₂SO₄(aq), K₂SO₄(aq), (NH₄)₂SO₄(aq), and sulphates MgSO₄(aq), MnSO₄(aq), NiSO₄(aq), CuSO₄(aq), and ZnSO₄(aq) were determined experimentally at a temperature of 298.15 K with a hygrometric method, at molalities in the range from 0.1 mol·kg⁻¹ to saturation. The osmotic coefficients are calculated from these results. The coefficients of Pitzer’s model was used to fit the osmotic coefficients for each salt solution. These parameters were used to predict solute activity coefficients for the salts studied.     

Hydroacridines XXV [1]. First Synthesis of (4aα,8aα,9aβ,10aβ)-Tetradecahydroacridine and New Syntheses of (4aα,8aα,9aα,10aβ)- and (4aα,8aβ,9aα,10aβ)-Tetradecahydroacridine

Summary. On heating in dry DMSO, in the presence of potassium t-butoxide, the N-nitrosamine of (4aα,8aβ,9aβ,10aα)-tetradecahydroacridine is completely converted into the N-nitrosamine of (4aα,8aα,9aα,10aβ)-tetradecahydroacridine. Under similar conditions, the N-nitrosamine of (4aα,8aα,9aβ,10aα)-tetradecahydroacridine yields a ternary equilibrium mixture containing itself (19%), and the N-nitrosamines of (4aα,8aβ,9aα,10aβ)-tetradecahydroacridine (46%) and the so far unknown (4aα,8aα,9aβ,10aβ)-tetradecahydroacridine (35%). The resulting N-nitrosamines can be smoothly denitrosated to the corresponding secondary amines.     

Synthese der isomeren 3, 4-Dimethyl-4-phenyl-3, 4-dihydro-carbostyrile

Cyclisation of 2-methyl-3-phenyl-but-3-en-anilide (III) with polyphosphoric acid gave cis-3, 4-dimethyl-4-phenyl-3, 4-dihydro-carbostyril (VII) in 61% yield together with a small amount of 2, 3-dimethylindenone (VIII), whereas with AlCl₃ a phenyl group was split off to give 3, 4-dimethylcarbostyril (VI). The anilide III isomerises to cis- and trans-2, 3-dimethyl-cinnam-anilide (IV resp. V) under basic conditions. The anilides IV and V gave only small yields of the dihydrocarbostyril VII with polyphosphoric acid. Chlorination of VII in position 3 using PCl₅ yielded IX which, on splitting out HCl, gave 3-methylene-4-methyl-4-phenyl-3, 4-dihydro-carbostyril (X). X was converted to trans-3, 4-dimethyl-4-phenyl-3, 4-dihydro-carbostyril (XI) by catalytic hydrogenation.     

Oxidative dealkylation of 4a-alkylated 4a,5-dihydroflavins: Properties of 4a-alkylated flavin radicals

Covalent coenzyme substrate adducts (“σ-complexes”) are probable intermediates in flavin-dependent biological dehydrogenations. As chemical model reaction for the σ-complex decay, oxidative dealkylation of stable 4a-alkyl-4a,5-dihydroflavins was studied as a function of alkyl mobility and nature of the oxidizing agent. The alkyl groups studied were n-propyl, allyl and benzyl, the oxidizing agents ³O₂, ¹O₂^*, nitroxide radical, ferricyanide and light-excited flavin.For all three alkyl residues, the primary reaction is formation of the 4a-alkyl-4a-hydroflavin radical by le^?-abstraction. ³O₂ and ferricyanide are too weak to initiate this step. If, however, the radical 4a-RFl is once formed, at least five decay modes can be observed depending on the nature of R:(1) For saturated R the exclusive decay is back transfer of the electron initially abstracted. In this case, dealkylation can only be obtained with ¹O₂*, albeit with the relatively slow rate of < 10⁶ M^?1s^?1.(2) For unsaturated R further 1e^?-oxidation leads to quantitative formation of oxidized flavin, while the fate of the alkyl group is still uncertain: In any case, ROH and the corresponding aldehydes as well as the dimers R₂ can be excluded as products.(3) Further oxidation by ³O₂ again leads to a quantitative yield of oxidized flavin while the alkyl residues are converted to peroxy radicals. In an autocatalytic reaction they form the corresponding hydroperoxides with starting 4a-R-Fl_redH, leading to acrolein (R = allyl) or benzaldehyde (R = benzyl) as the major products.(4) In the absence of further oxidant, slow intramolecular alkyl migration is observed leading to the stable 5-alkyl-l,5-dihydroflavin isomer.(5) Competitively, alkyl migration occurs intermolecularly with the starting material as carbenium acceptor, resulting in formation of the stable 4a,5-dialkyl-4a,5-dihydroflavin and unsubstituted radical HFl, which disproportionates.     

4a-Alkyl Derivatives of 5-Oxo-4H-4a,5-dihydroindeno[1,2-b]pyridine

High selectivity has been discovered for the C-alkylation of ambident anions of 5-oxo-1H-4,5-dihydroindeno[1,2-b]pyridines with ethyl bromoacetate, allyl, propargyl, and phenacyl bromides, which leads to the formation of the corresponding 4a-substituted 5-oxo-4H-4a,5-dihydroindeno[1,2-b]pyridines in high yield.     

Stabilization Studies on Divalent Five‐Membered Rings C4H4C,C4H4Si,C4H4Ge,C4H4Sn,and C4H4Pb

Energy differences, ΔX_S‐t (X = E, H and G) (ΔX_S‐t = X_(singlet)‐X_(triplet)) between singlet (s) and triplet (t) states are calculated at B3LYP/6‐311++G (3df,2p). The DFT calculations show that the triplet state of C₄H₄C is a ground state with planar conformer respect to its corresponding nonplanar singlet state. Both singlet and triplet states of C₄H₄M (M = Si, Ge, Sn and Pb) have a planar conformer with the singlet ground state. Four isodesmic reactions are presented for determining the stability energies, SE. NICS calculations are carried out for C₄H₄M to determine the aromatic character.     

Reactivity of 4a,5-epoxy-5-deazaflavins

Reactions of 4a,5-epoxy-5-deazaflavins with aqueous potassium carbonate, Vilsmeier reagent (dimethylformamide-phosphorus oxychloride), acetic anhydride-acetic acid, pyridine and triethanolamine gave the corresponding oxazolonoquinolines, 5-chloro-5-deazaflavins, 4a,5-diacetoxy-5-deazaflavins, 1,5-dihydro-5-deazaflavin-5-ones, and deoxygenated 5-deazaflavins, respectively.     

Synthesis, characterization, and study of octanuclear iron-oxo clusters containing a redox-active Fe4O4-cubane core

A one-pot synthetic procedure yields the octanuclear Fe(III) complexes Fe(8)(micro(4-)O)(4)(micro-pz(*))(12)X(40, where X = Cl and pz(*) = pyrazolate anion (pz = C(3)H(3)N(2)-) (1), 4-Cl-pz (2), and 4-Me-pz (3) or X = Br and pz(*) = pz (4). The crystal structures of complexes 1-4, determined by X-ray diffraction, show an Fe(4)O(4)-cubane core encapsulated in a shell composed of four interwoven Fe(micro-pz(*))(3)X units. Complexes 1-4 have been characterized by 1H NMR, infrared, and Raman spectroscopies. M?ssbauer spectroscopic analysis distinguishes the cubane and outer Fe(III) centers by their different isomer shift and quadrupole splitting values. Electrochemical analyses by cyclic voltammetry show four consecutive, closely spaced, reversible reduction processes for each of the four complexes. Magnetic susceptibility studies, corroborated by density functional theory calculations, reveal weak antiferromagnetic coupling among the four cubane Fe centers and strong antiferromagnetic coupling between cubane and outer Fe atoms of 1. The structural similarity between the antiferromagnetic Fe(8)(micro(4-)O)(4) core of 1-4 and the antiferromagnetic units contained in the minerals ferrihydrite and maghemite is demonstrated by X-ray and M?ssbauer data.     

Vibrational spectroscopic investigation of structurally-related LiFePO4, NaFePO4, and FePO4 compounds

Vibrational spectroscopy was utilized to investigate the local structure of LiFePO(4), NaFePO(4), and FePO(4). The factor group splitting of the intramolecular PO(4)(3-) vibrations is between 10 and 20 cm(-1) less for NaFePO(4) than for LiFePO(4). This is because Li(+) ions have a higher charge density than Na(+) ions and can form stronger coordinative bonds with the PO(4)(3-) anions. Thus, the internal modes are more perturbed in LiFePO(4) and exhibit larger factor group splitting effects. The similarity of the factor group multiplets for both LiFePO(4) and NaFePO(4), particularly the PO(4)(3-) bending modes, strongly suggests that the 506 and 470 cm(-1) bands of LiFePO(4) consist almost entirely of lithium translatory motion. There are marked differences between the vibrational spectrum of FePO(4) and those of LiMPO(4) (M=Mn, Fe, Co, or Ni) or NaFePO(4). The monovalent cations interact with the oxygen atoms of the phosphate groups, affecting the frequencies and intensities of the intramolecular PO(4)(3-) modes, in a manner that is absent in FePO(4).     

Syntheses, structure, and properties of a manganese-calcium cluster containing a Mn4Ca2 core

We describe here a novel, simple, efficient self-assembly method for the in situ generation of [Mn4Cl4(micro-OCH2CH2OMe)4(EtOH)4] and [Mn4(micro-Cl)Cl3(micro-OCH2CH2OMe)4(HOCH2CH2OMe)3]2 cubane-type compounds which react readily with calcium species to form cluster [Mn4Ca2Cl4(micro-OCH2CH2OMe)8], the calcium atoms attached to the Mn4 unit of flatten out the cubane inducing significant conformational changes.     

Comparison of the crystal structures of sodium orthosilicate,Na4SiO4, and sodium orthogermanate,Na4GeO4

The crystal structures of Na₄SiO₄ and Na₄GeO₄ are isotypic, despite a difference in coordination numbers: in Na₄SiO₄ only one of the four symmetrically independent sodium atoms is four coordinated, in Na₄GeO₄ two of them are.

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Vergleich der Kristallstrukturen von Natriumorthosilikat, Na₄SiO₄, und Natriumorthogermanat, Na₄GeO₄ (Kurze Mitteilung)

Zusammenfassung Die Kristallstrukturen von Na₄SiO₄ und Na₄GeO₄ sind isotyp, trotz eines Unterschiedes in den Koordinationszahlen: im Na₄SiO₄ ist nur eines der symmetrisch unabhängigen Natriumatome vierfach koordiniert, während es im Na₄GeO₄ derer zwei sind.

     

The crystal structure of LaIr4B4, ThOs4B4, ThIr4B4 (NdCo4B4-type) and URu4B4, UOs4B4 (LuRu4B4-type)

The crystal structure of LaIr₄B₄ has been refined from single crystal counter data. LaIr₄B₄ is tetragonal,P4₂/n,Z=2, isotypic with NdCo₄B₄, |F|/|F _o|=0.039 for 312 independent reflections [|F _o|>2 (F _o)]. ThIr₄B₄ and ThOs₄B₄ also belong to the NdCo₄B₄-type structure. URu₄B₄ and UOs₄B₄ were found to crystallize with LuRu₄B₄-type structure. The crystal chemistry of (RE)T ₄B₄-phases is discussed and simple geometric relations are shown to exist between them.Dedicated to Prof.B. T. Matthias in celebration of his 60th birthday.     

(CuI)3P4S4: preparation,structural, and NMR spectroscopic characterization of a copper(I) halide adduct with beta-P4S4

(CuI)(3)P(4)S(4) is obtained by reaction of stoichiometric amounts of CuI, P, and S in evacuated silica ampoules. The yellow compound consists of monomeric beta-P(4)S(4) cage molecules that are separated by hexagonal columns of CuI. (CuI)(3)P(4)S(4) crystallizes isotypic to (CuI)(3)P(4)Se(4) in the hexagonal system, space group P6(3)cm (no. 185) with a=19.082(3), c=6.691(1) A, V=2109.9(6) A(3), and Z=6. Three of the four phosphorus atoms are bonded to copper, whereas no bonds between copper and sulfur are observed. The two crystallographically distinct copper sites are clearly differentiated by (65)Cu magic-angle spinning (MAS) NMR spectroscopy. Furthermore, an unequivocal assignment of the (31)P MAS-NMR spectra is possible on the basis of homo- and heteronuclear dipole-dipole and scalar interactions. Dipolar coupling to the adjacent quadrupolar spins (63, 65)Cu generates a clear multiplet structure of the peaks attributable to P1 and P2, respectively. Furthermore, the utility of a newly developed two-dimensional NMR technique is illustrated to reveal direct connectivity between P atoms based on ((31)P-(31)P) scalar interactions.