Synthesis in the diazasteroid group. III . Syntheses of the 8,16- and 8,17-diazasteroid systems

By using 3-pyrrolidone derivatives as a source of the D ring, the following five diazasteroids were synthesized: 8,16-diaza-2,3-dimethoxy-15,15,16-trimethylgona-1,3,5(10),13-tetraen-12-one (VII), 8,16-diaza-2,3-dimethoxy-16-acetylgona-1,3,5(10),13-tetraen-12-one (X), 8,17-diaza-2,3-dimethoxy-17-acetylgona-1,3,5(10),13-tetracn-12-one (XI), 8,16-diaza-16-acetylgona-1,3,5(10), 13-tetraen-12-one (XII), and 8,17-diaza-17-acetylgona-1,3,5(10),13-tetraen-12-one (XIII).     

Complete assignments of 1H and 13C NMR spectral data for three sesquiterpenoids from Inula helenium

The complete assignments of all the (1)H and (13)C NMR signals of three sesquiterpene lactones, 4-oxo-5(6),11-eudesmadiene-8,12-olide (1), 4-oxo-11-eudesmaene-8,12-olide (2) and (1(10)E)-5beta-Hydroxygermacra-1(10),4(15),11-trien-8, 12-olide (3), were carried out by various 2D NMR experiments. Compounds 1-3 were isolated from the roots of Inula helenium for the first time. Among them, 1 was identified as a new nor-sesquiterpene lactone, and 2 was isolated from a natural source for the first time. The (13)C-NMR data of compound 3 was also reported for the first time.     

From achiral ligands to chiral coordination polymers: spontaneous resolution, weak ferromagnetism, and topological ferrimagnetism

Using the achiral diazine ligands bearing two bidentate pyridylimino groups as sources of conformational chirality, five azido-bridged coordination polymers are prepared and characterized crystallographically and magnetically. The chirality of the molecular units is induced by the coordination of the diazine ligands in a twisted chiral conformation. The use of L(1) (1,4-bis(2-pyridyl)-1-amino-2,3-diaza-1,3-butadiene) and L(2) (1,4-bis(2-pyridyl)-1,4-diamino-2,3-diaza-1,3-butadiene) induces spontaneous resolution, yielding conglomerates of chiral compounds [Mn(3)(L(1))(2)(N(3))(6)](n) (1) and [Mn(2)(L(2))(2)(N(3))(3)](n)(ClO(4))(n).nH(2)O (2), respectively, where triangular (1) or double helical (2) chiral units are connected into homochiral one-dimensional (1D) chains via single end-to-end (EE) azido bridges. The chains are stacked via hydrogen bonds in a homochiral fashion to yield chiral crystals. When L(3) (2,5-bis(2-pyridyl)-3,4-diaza-2,4-hexadiene) is employed, a partial spontaneous resolution occurs, where binuclear chiral units are interlinked into fish-scale-like homochiral two-dimensional (2D) layers via single EE azido bridges. The layers are stacked in a heterochiral or homochiral fashion to yield simultaneously a racemic compound, [Mn(2)(L(3))(N(3))(4)](n) (3a), and a conglomerate, [Mn(2)(L(3))(N(3))(4)](n).nMeOH (3b). On the other hand, the ligand without amino and methyl substituents (L(4), 1,4-bis(2-pyridyl)-2,3-diaza-1,3-butadiene) does not induce spontaneous resolution. The resulting compound, [Mn(2)(L(4))(N(3))(4)](n) (4), consists of centrosymmetric 2D layers with alternating single diazine, single EE azido, and double end-on (EO) azido bridges, where the chirality is destroyed by the centrosymmetric double EO bridges. These compounds exhibit very different magnetic behaviors. In particular, 1 behaves as a metamagnet built of homometallic ferrimagnetic chains with a unique "fused-triangles" topology, 2 behaves as a 1D antiferromagnet with alternating antiferromagnetic interactions, 3a and 3b behave as spin-canted weak ferromagnets with different critical temperatures, and 4 also behaves as a spin-canted weak ferromagnet but exhibits two-step magnetic transitions.     

Quinone-type podocarpanes from the bark of Taiwania cryptomerioides

Three quinone-type podocarpanes, 3beta-hydroxy-13-methoxy-8,12-podocarpadiene-11,14-dione (1), 18-hydroxy-13-methoxy-8,12-podocarpadiene-11,14-dione (2), and 13-methoxy-8,12-podocarpadiene-2,11,14-trione (3) were isolated from the bark of Taiwania cryptomerioides. Their structures were elucidated using spectral methods.     

A Diastereoselective Synthesis of trans/cis Octahydronaphthoquinolizine

The tetracyclic system of 2,3,6,7,7a,8,12b,12c-octahydro-lH,5H-naphtho[1,2,3,i,j]quinolizine with trans/cis fusions of the B/D and B/C rings has been diastereospecifically synthesized in nine steps and in 23% total yield.     

Spectroscopic and electrochemical investigation with coordination stabilities: mononuclear manganese(II) complexes derived from different constituents macrocyclic ligands

Since the manganese(II) complexes are known as having a high degree of stability, some of them may be able to play a very important role in biosystems. We prepared manganese(II) complexes with different chromospheres containing macrocyclic ligands bearing N, S and O like functional donor atoms in order to obtain different models of compounds. So these new manganese(II) complexes were derived from macrocyclic ligands by chelating them with metal ions. Thus, two macrocyclic ligands, L(1): 2,4-diphenyl-1,5-diaza-8,12-dioxo-6,7:13,14-dibenzocyclo tetradeca-1,4-diene[N(2)O(2)]ane; L(2): 2,4,9,11-tetraphenyl-6,13-dimethyl-1,5,8,12-traazacyclotertr-adeca-1,4,8,11-tetraene[N(4)]ane; and two more different form first one viz.-L(3): 1,7-diaza-4-monothia-10,14-dioxo-8,9:15,16-cyclohexadecane[N(2)O(2)S]ane and L(4): 4,13-diaoxa-1,7,10,16-hexazacyclooctadecane[N(4)O(2)]ane were prepared and their capacity to retain the manganese(II) ion in solid as well as aqueous solution was determined from various physiochemical techniques viz: characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, IR, electronic, ESR spectral studies and cyclic voltammetric measurements.     

New Sesquiterpenes from Ligulariopsis Shichuana

A thorough investigation of Ligulariopsis shichuana afforded five new sesquiterpenes, including 1β,10β‐epoxy‐3α‐angeloyloxy‐9β‐acetoxy‐8α,11β‐dihydroxybakkenolide ( 1 ), 1β,7‐dihydroxy‐3β‐acetoxy‐noreremophil‐6(7),9(10)‐dien‐8‐one ( 2 ), 8α‐hydroxy‐3‐oxoeremophil‐1(2),7(11),9(10)‐trien‐8β(12)‐olide ( 3 ), 1β,10β‐dihydroxy‐3β‐acetoxyeremophil‐7(11),8(9)‐dien‐8(12)‐olide ( 4 ) and 1β,10β‐epoxy‐8,12‐dihydroxy‐3β‐acetoxy‐9β‐angeloyloxyeremophil‐7(11)‐en‐8,12‐disemiketal ( 5 ). Their structures were established by spectroscopic methods and 2D NMR techniques. In addition, bakkenolide ( 1 ) and eremophilenolides ( 5 ) showed antibacterial and cytotoxic activities.     

Pt(II)-mediated nitrile-tetramethylguanidine coupling as a key step for a novel synthesis of 1,6-dihydro-1,3,5-dihydrotriazines

The coupling between tetramethylguanidine, HN=C(NMe2)2, and coordinated organonitriles in the platinum(II) complexes cis/trans-[PtCl2(RCN)2] (R = Me, Et, Ph) proceeds rapidly under mild conditions to afford the diimino compounds containing two N-bound monodentate 1,3-diaza-1,3-diene ligands [PtCl2{NH=C(R)N=C(NMe2)2}2] (R = Et, trans-1; R = Ph, trans-2; R = Me, cis-3; R = Et, cis-4), and this reaction is the first observation of metal-mediated nucleophilic addition of a guanidine to ligated nitrile. Complexes 1-4 were characterized by elemental analyses (C, H, N), X-ray diffraction, FAB mass spectrometry, IR, and 1H and 13C{1H} NMR spectroscopies; assignment of signals from E/Z-forms of 1,3-diaza-1,3-diene ligands and verification of routes for their Z right harpoon over left harpoon E isomerization in solution were performed using 2D 1H,1H-COSY, 1H,13C-HETCOR, and 1D NOE NMR experiments. The newly formed and previously unknown 1,3-diaza-1,3-dienes NH=C(R)N=C(NMe2)2 were liberated from the platinum(II) complexes [PtCl2{NH=C(R)N=C(NMe2)2}2] (1-3) by substitution with 2 equiv of 1,2-bis-(diphenylphosphino)ethane (dppe) to give the uncomplexed HN=C(R)N=C(NMe2)2 species (5-7) in solution and the solid [Pt(dppe)2](Cl)2. The former were utilized in situ, after filtration of the latter, in the reaction with 1,3-di-p-tolylcarbodiimide, (p-tol)N=C=N(tol-p), in CDCl3 to generate (6E)-N,N-dimethyl-1-(4-methylphenyl)-6-[(4-methylphenyl)imino]-1,6-dihydro-1,3,5-triazin-2-amines) (8-10) due to the [4 + 2]-cycloaddition accompanying elimination of HNMe2. The formulation of 8-10 is based on ESI-MS, 1H, 13C{1H} NMR, and X-ray crystal structures determined for 9 and 10. The reaction of 1,3-diaza-1,3-dienes with 1,3-di-p-tolylcarbodiimide, described in this article, constitutes a novel synthetic approach to a useful class of heterocyclic species like 1,6-dihydro-1,3,5-triazines.     

Synthesis and Metal Complex Formation of Nitrogen-Oxygen Donor Macrocyclic Ligands

Reduction of 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacylotetradecane-5,11-diene( 1 ) with sodium borohydride in ethanol generates 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacyclotetradecane( 2 ) in high yield. The macrocyclic ligand 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacyclotetradecane-N,N′-diacetic acid ( 3 ) has been synthesized and characterized. In addition, reaction of ( 2 ) with an excess of acrylonitrile gives 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacyclotetradecane-N,N′-di(2-cyanoethyl) ( 4 ). Several new complexes of these ligands with nickel(II), copper(II) and cobalt(II) have been prepared and identified. The structures of these complexes are proposed on the basis of elemental analysis, ¹H, ¹³C-NMR, IR, UV-VIS spectra, magnetic susceptibility and conductivity data.     

Four Novel Eremophilanolides from Ligularia sagitta

Four new eremophilanolides, isolated from Ligularia sagitta, were identified as (1β,3β,6β,8β,10β)‐6‐acetoxy‐3‐(angeloyloxy)‐1,10‐epoxy‐8‐hydroxyeremophil‐7(11)‐en‐8,12α‐olide ( 1 ), (1β,3β,6β,8β,10β)‐3‐(angeloyloxy)‐1,10‐epoxy‐6,8‐dihydroxyeremophil‐7(11)‐en‐8,12α‐olide ( 2 ), (1β,3β,6β,8β,10β)‐3‐(angeloyloxy)‐1,10‐epoxy‐8‐ethoxy‐6‐hydroxyeremophil‐7(11)‐en‐8,12α‐olide ( 3 ), and (1β,3β,8β,10β)‐3‐(angeloyloxy)‐1,10‐epoxy‐8‐hydroxyeremophil‐7(11)‐en‐8,12α‐olide ( 4 ). Their structures were elucidated by spectroscopic methods, including 2D‐NMR techniques and chemical transformations.     

New supramolecular isomers with 2D 4(4) square-grid and 3D 6(5).8 frameworks in a one-pot synthesis; reversible solvent uptake and intriguing luminescence properties

Two supramolecular isomers of [Ni(4-bpd)(2)(NCS)(2)] (4-bpd = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) with 2D 4(4) square-grid and 3D 6(5).8 frameworks are co-crystallized in a one-pot reaction, both of which exhibit interesting luminescence properties and reversible adsorption-desorption with respect to guest solvents.     

Synthesis in the diazasteroid group. I. A new synthesis of 8,13-diaza-2,3-dimethoxygona-1,3,5(10)triene and its mercuric acetate oxidation

From the condensation reaction of methyl butyrolactim (I) with 1-ethoxycarbonylmethyl-6,7-dimethoxy-l,2,3,4-tetrahydroisoquinoline (II), 8,13-diaza-2,3-dimethoxygona-l,3,5(10)trien-12-one (VI) and 8,13-diaza-2,3-dimethoxygona-l,3,5(10)triene (VII) were obtained in good yield. The oxidation of VI and VII with mercuric acetate was examined.     

Straightforward access to pyrazines, piperazinones, and quinoxalines by reactions of 1,2-diaza-1,3-butadienes with 1,2-diamines under solution, solvent-free, or solid-phase conditions

The preparation of tetrahydropyrazines, dihydropyrazines, pyrazines, piperazinones, and quinoxalines by 1,4-addition of 1,2-diamines to 1,2-diaza-1,3-butadienes bearing carboxylate, carboxamide, or phosphorylated groups at the terminal carbon and subsequent internal heterocyclization is described. The solvent-free reaction of carboxylated 1,2-diaza-1,3-butadienes with the same reagents affords piperazinones, while phosphorylated 1,2-diaza-1,3-butadienes yield phosphorylated pyrazines. The solid-phase reaction of polymer-bound 1,2-diaza-1,3-butadienes with 1,2-diamines produces pyrazines.     

2,2-Difluor-1,2,3-trimethyl-1,3-diaza-2λ5-phospholidin

2,2-Difluoro-1,2,3-trimethyl-1,3-diaza-2λ⁵-phospholidine The title compound 1 is obtained in about 50% yield by oxidative fluorination of 1,2,3-trimethyl-1,3-diaza-2λ³-phospholidine, 6 , with IF₅. 1 is characterized by its nmr, mass, and ir spectra.     

Design, synthesis and evaluation of diazadibenzocrown ethers as Pb(2+) extractants and carriers in plasticized cellulose triacetate membranes

The ligands 4,7-diaza-2,3,8,9-dibenzo-15-crown-5 (L1), 4,10-diaza-2,3,11,12-dibenzo-18-crown-6 (L2), 4,10-diaza-2,3,11,12-di(4′-tert-butylbenzo)-18-crown-6 (L3) and N,N-di(methylenecarboxyethoxy) 4,10-diaza-2,3,11,12-dibenzo-18-crown-6 (L4) have been prepared. Partition coefficients and acid dissociation constants for these four diazadibenzocrown ether compounds were determined in water-chloroform. Their effectiveness was assessed in solvent extraction of Pb²⁺ from aqueous solutions into toluene. Ligands L3 and L4 provide high selectivity for Pb²⁺ over Cd²⁺ and Zn²⁺ in transport across plasticized cellulose triacetate membranes.     

Synthesis and transformations of polyhedral compounds

Derivatives of 1,3-diaza- and 1,3,5-triazaadamantanes react with 1,2-dibromoethane in the presence of base to give derivatives of 1,4-diaza- and 1,3,6-triazahomoadamantanes, respectively. Schiff bases were obtained containing the 1,3,6-triazahomoadamantane ring.For Communication 14 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1098–1100, August, 1992.     

Theoretical study of reaction pathways to borazine

Four reaction pathways from diborane and ammonia to borazine, (HBNH)3, have been studied computationally at the density functional level (B3LYP/6-311+G(2d,p)//B3LYP/6-31G(d)). The cycloaddition of H2BNH2 to 1,3-diaza-2,4-diborabuta-1,3-diene and subsequent elimination of two molecules of H2 was found to be the lowest-energy pathway to (HBNH)3. In the other pathways, the formation and conversion of the intermediates 1,3,5-triaza-2,4,6-triborahexatriene, cyclotriborazane, and 1,3,5-triaza-2,4,6-triborahexa-1,5-diene into (HBNH)3 were investigated. The formation of 1,3-diaza-2,4-diborabuta-1,3-diene and, subsequently, the formation and electrocyclization of 1,3,5-triaza-2,4,6-triborahexatriene and the cycloaddition of H2BNH2 to 1,3-diaza-2,4-diborabuta-1,3-diene are predicted to be the kinetically favored pathways to (HBNH)3 in the gas phase. At low concentrations of 1,3-diaza-2,4-diborabutene, high concentrations of H2BNH2, and a temperature of 298.15 K, the formation of the polyolefins H3BNH2(H2BNH2)nNHBH2 (n=1,2) is predicted to be competitive with the formation of 1,3-diaza-2,4-diborabuta-1,3-diene.     

Stoichiometry and conformation of the azacrown moiety in sodium complexes of azacrown ethers. A Raman/IR spectroscopic study. Part II: Complexes of 4,13-diaza-15-crown-5

4,13-Diaza-15-crown-5 and three of its sodium complexes (bromide, iodide and thiocyanate) were studied using Raman and IR spectroscopy and normal coordinate calculations, following the corresponding study on the sodium complexes of 4,13-diaza-18-crown-6 in the preceding paper. Complex formation was again accompanied by a characteristic shift of the bands, especially of those in the 800–900 cm^–1 region. The complexes of 4-13-diaza-15-crown-5 were distinct from those of 4-13-diaza-18-crown-6, in that both of the bands at 830 and 890 cm^–1 of the parent azacrown were affected on complex formation and in that only the 11 complex was formed. Normal mode calculations were made to predict conformations of the azacrown ring of the parent 4,13-diaza-15-crown-5 and its sodium complexes. Attention was paid to the different extent of mismatch in size of a sodium ion and azacrown cavities.     

Chlorosulfonyl isocyanate reactions with N-(alkoxycarbonyl)-2-azabicyclo[2.2.0]hex-5-enes. Regiospecific two-atom insertion pathways

Addition of the uniparticulate electrophile chlorosulfonyl isocyanate to the nitrogen atom of N-(alkoxycarbonyl)-2-azabicyclo[2.2.0]hex-5-enes 1 is followed by ring cleavage and recombination. The parent 4-methyl, 5-methyl, 5-bromo, and 5-phenyl azabicycles 1a-f afforded novel 2,4-diaza-3-oxo-bicyclo[4.2.0]oct-7-enes 10a-f. The 3-endo-phenyl azabicycle 1g rearranged to a 6-styryl-1,3-diaza-2-oxo-cyclohex-4-ene 12.     

Reactions of 1,2-diaza-1,3-dienes with thiol derivatives: a versatile construction of nitrogen/sulfur containing heterocycles

The synthesis of substituted 2,3-dihydro-1,4-thiazines, fused cycloalkyl-1,4-thiazines, 1,4-benzothiazines and fused cycloalkyl-1,4-benzothiazines by 1,4-addition of 1,2-aminothiols to 1,2-diaza-1,3-dienes bearing carboxylate, carboxamide, or phosphorylated groups and subsequent internal heterocyclization is described. The reaction of carboxylated 1,2-diaza-1,3-butadienes with 2-(butylamino)ethanethiol affords 1,4-thiazinan-3-ones. The solid-phase reaction of polymer-bound 1,2-diaza-1,3-butadienes with 1,2-aminothiols produces 2,3-dihydro-1,4-thiazines and 1,4-benzothiazines.