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One-dimensional (1D) coordination polymers (CPs) featuring three different topologies, comprising zig-zag, ribbon-like and poly-[n]-catenane structures, were obtained by reaction of Hg(II) ions with a novel bispidine ligand L3, and structurally characterized by SC- and P-XRD methods. The CPs obtained in the form of microcrystalline powders were tested for their ability to undergo solvent adsorption and exchange by P-XRD and

The synthesis and characterization of the two new open-chain ligands 1,15-bis-[6-(2,2'-bipyridyl)]-2,5,8,11,14-pentaaza-octadecane (L1) and 1,15-bis-[2-(1,10-phenanthroline)-9-methyl]-2,5,8,11,14-pentaazaoctadecane (L2), both featuring a tetraethylenpentaamine chain linking via methylene bridges the 6 and 2 positions of two identical 2,2'-bipyridyl (bpy) and 9-methyl-1,10-phenanthroline (9-methyl-phen) moieties respectively, are reported. Their protonation and binding ability for Cu2+ , Zn2+ , Cd2+ and Pb2+ have been studied by coupling potentiometric titrations with UV-vis absorption and fluorescence emission measurements in water. L1 and L2 afford stable mono- and dinuclear complexes, in which the metal ion is bound by a single bpy or 9-methyl-phen unit and the amine groups on the aliphatic chain. However, L1 displays a greater binding ability for Cu2+ and Zn2+ with respect to L2, the stability constants of the [ML1]2+ complexes being 21.8 (Cu2+ ) and 19.4 (Zn2+ ) log units vs 20.34 and 16.8 log. units for the corresponding L2 species. Among all the metal ions tested, only the Zn2+ complex with L2 features an enhanced fluorescence emission at neutral pH, thanks to the simultaneous binding of one Zn2+ ion and H+ ion(s), that inhibits any possible photoinduced electron transfer (PET) process from the amine donors to the excited phen moiety. Binding of a second metal switches off the emission again.

The complex, Mn(hfa)2•tmeda [(H-hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentandione, tmeda = N,N,N′,N′-tetramethylethylendiamine)], is synthesized in a single-step reaction and characterized by elemental analysis, thermal analysis, and infrared (IR) spectroscopy. The solid-state crystal structure of Mn(hfa)2•tmeda provides evidence of a mononuclear structure. The thermal analyses show that the complex is thermally stable and can be evaporated to leave less than 2% residue. The complex properties are compared with the first generation, commercially available MnII and MnIII precursors, Mn(acac)2 (Hacac = acetylacetone) and Mn(tmhd)3 (Htmhd = 2,2,6,6-tetramethyl-3,5-heptanedione), respectively. Mn(hfa)2•tmeda represents the first example of manganese(II) precursor that can be used in the liquid phase without decomposition, thus providing constant evaporation rates, even for long deposition times. It is successfully applied to the reduced-pressure, metal-organic (MO)CVD of the Mn3O4 phase.

Insertion of 1,2-disubstituted alkynes into (Pd(CH3)(CO)(BIOX)) + (B{3,5-(CF3)2C6H3}4) � (1), where BIOX = (4S,4'S)-(� )-4,4',5,5'-tetrahy- dro-4,4'-bis(1-methylethyl)-2,2'-biox- azole, leads to the formation of five- membered palladacycles, which, by re- action with carbon monoxide, produce a mixture of two diastereomeric forms of a palladium complex containing an h 3 -allylic g-lactone ligand. On leaving the mixture in solution, one isomer was converted into the other, reaching a di- astereomeric excess of up to 94 %. The steric and electronic factors responsible for the epimerization process were in- vestigated by theoretical methods. Cleavage of the h 3 -allylpalladium bond by nucleophiles allowed highly substituted chiral butenolides to be synthesized in good enantiomeric excess.

The synthesis and characterization of the new tetraazamacrocycle L, bearing two 1,1'-bis(2-phenol) groups as side-arms, is reported. The basicity behavior and the binding properties of L toward alkali metal ions were determined by means of potentiometric measurements in ethanol/water 50:50 (v/v) solution (298.1+/-0.1 K, I=0.15 mol dm(-3)). The anionic H(-1)L(-) species can be obtained in strong alkaline solution, indicating that not all of the acidic protons of L can be removed under the experimental conditions used. This species behaves as a tetraprotic base (log K(1)=11.22, log K(2)=9.45, log K(3)=7.07, log K(4)=5.08), and binds alkali metal ions to form neutral [MH(-1)L] complexes with the following stability constants: log K(Li)=3.92, log K(Na)=3.54, log K(K)=3.29, log K(Cs)=3.53. The arrangement of the acidic protons in the H(-1)L(-) species depends on the polarity of the solvents used, and at least one proton switches from the amine moiety to the aromatic part upon decreasing the polarity of the solvent. In this way two different binding areas, modulated by the polarity of solvents, are possible in L. One area is preferred by alkali metal ions in polar solvents, the second one is preferred in solvents with low polarity. Thus, the metal ion can switch from one location to the other in the ligand, modulated by the polarity of the environment. A strong hydrogen-bonding network should preorganize the ligand for coordination, as confirmed by MD simulations. The crystal structure of the [Na(H(-1)L)].CH(3)CN complex (space group P2(1)/c, a=12.805(1), b=20.205(3), c=14.170(2) A, beta=100.77(1) degrees, V=3601.6(8) A(3), Z=4, R=0.0430, wR2=0.1181), obtained using CH(2)Cl(2)/CH(3)CN as mixed solvent, supports this last aspect and shows one of the proposed binding areas.

A new dinuclear CuII complex with a unique structural arrangement and containing a doubly bridged macrocyclic ligand has been prepared from two different routes, one of which involves the reaction of oxygen and a CuI precursor, thus mimicking the cresolase activity of tyrosinase

The compound [2-(1-diethylaminopropyl)] 1-hydroxy-1,1′-bicyclohexyl-2-carboxylate 1 is a muscarinic antagonist characterized by the presence of three chiral atoms and eight possible stereoisomers. The binding affinities to the five cloned m1–m5 muscarinic receptors of the stereoisomers of 1 were previously investigated and proved to be related to the chirality of the molecules. The eight isomers are prepared through the synthesis of their racemates followed by chemical resolution as (+) and (−) tartrate or (+) and (−) dibenzoyltartrate salts. The isomers with cis-configuration of OH and COOH substituents of the cyclohexane are also obtained by coupling optically active (1S, 2S) or (1R,2R)-1-hydroxy-[1,1′-bicyclohexyl]-2-carboxylic acid with (S)- or (R)-1-diethylamino-2-propanol. Chiral GC and HPLC methods are used to determine their optical purity. The absolute configurations of the four cis- and four trans-isomers are established by stereospecific synthesis and X-ray crystallographic data. Chirality 9:713–721, 1997. © 1997 Wiley-Liss, Inc.

The reaction between ethyl (Z)-3-dimethylamino-2-isocyanoacrylate (1) and arenesulfenyl chlorides (6a-c) afforded the unexpected imidazolyl- oxazolones (7a-c). The structure of compounds (7a-c) was in agreement with their 1 H nmr, ir and ms data and was confirmed by X-ray analysis of (7a)

The enantiomers of 1-methyl-3-(10H-phenothiazine-10-ylmethyl)-1-azoniabicyclo[2,2,2]octane iodide (1) were prepared by chiral chromatographic resolution of the precursor mequitazine (2). The (+)-(S)-enantiomer 1b is 10-fold more potent than (−)-(R)-enantiomer 1a as a histamine antagonist, while the two enantiomers show the same antimuscarinic activity in vitro. The absolute configuration of the more active dextrorotatory isomer has been determined by X-ray analysis. Conformational analysis and molecular modeling suggest that the (+)-(S)-enantiomer can adopt a conformation similar to that attributed to the receptor binding conformers of classical antihistamines. © 1994 Wiley-Liss, Inc.

The reaction between 2-substituted ethyl 2,5-dihydro-5-oxoisoxazole-4-carboxylates (2a,b) and heterocyclic amines 1, 4, and 6, having the amino group in position 2 with respect to the nuclear nitrogen afforded fused pyrimidines 3, 5, and 7.

The title compound 2 is found to undergo thermal isomerization into the quinoxaline derivative 3, as shown by a crystal structure determination of the latter; a mechanistic rationale for this unusual rearrangement is suggested.

The synthesis and characterization of the new azamacrocycle 4,10,15-trimethyl-1,4,7,10,15-pentaazabicyclo[5.5.5]heptadecane (L) are reported. The stepwise basicity constants have been determined by potentiometry (25C, NaCl 0.15 mol dm[sup [minus]3]). L behaves as biprotic base: log K[sub 1] = 11.8; log K[sub 2] = 10.0. The molecular structure of the monoprotonated salt [HL][BPh[sub 4]] has been determined by single-crystal X-ray analysis. The structure of [HL]+ shows the five nitrogen atoms in endo configuration, indicating that the proton is inside the cage cavity. Geometrical considerations indicate that the proton is bound to the bridgehead nitrogen atom N(2). The cage L selectivity encapsulates Li+, and the equilibrium for the formation of the inclusion complex [LiL]+ has been investigated by potentiometry (log K = 5.5) and [sup 7]Li NMR techniques. The molecular structure of the complex [LiL][BPh[sub 4]] has been determined by single-crystal X-ray analysis. Li+ is wholly enclosed in the cage cavity adopting a regular bipyramidal geometry with the Li-N distances for the 2.01-2.08-[angstrom] range. Cu(II) is also encapsulated by L; the electronic spectra of the complex show essentially the same features in the solid state and in solution and are diagnostic of a five-coordinate trigonal-bipyramidal structure.

The reaction between 2-hydroxybenzaldehyde (1a), isocyanides 2, and ammonium formate, in the conditions of the Ugi four-component condensation, affords 2-alkylamino- and 2-arylamino-3-[(2-hydroxybenzylidene)amino]benzofurans 3a-c. Analogously by employing 5-bromo-2-hydroxybenzaldehyde (1b) as the carbonyl compound, 2-alkylamino- and 2-arylamino-5-bromo-3-[(5-bromo-2-hydroxybenzylidene)amino]benzofurans 3d-f are obtained

3,5-Dimethyl-4-nitroisoxazole (1) was found to undergo tandem condensation-cyclization processes with 4-(1-cylopenten-1-yl)- and 4-(1-cyclohexen-1-yl)morpholine in ethanol solution to give, through the intermediates (4) and (7), the N-oxides (5) and (9) respectively. The reactivity of 1 towards 1-diethylamino-propyne in different solvents was also investigated; the structure of the unexpected acycloxime (13), coming from the above reagents in acetonitrile, was determined by an X-ray analysis. Plausible mechanistic pathways for these new reactions are suggested

A new series of 11-[(aminoalkyl) carbonyl] derivatives of 6,11-dihydrobibenzo [c,f] [1,2,5] thiadiazepine 5,5-dioxide (10-39) were synthesized and evaluated for potential antidepressant activity in the apomorphine-induced hypothermia (Apo 16) tests. Effects on reserpine-induced hypothermia and toxicity for the most potent antagonists of Apo 16 hypothermia were also studied. Structure-activity relationships are reported. Anticholinergic effects were evaluated for compound 12, identified as the most potent and least toxic in this series, by assessing physostigmine lethality. Compound 12 was also subjected to X-ray analysis

The synthesis and characterization of the new macrotricycle 10,22,28,32-tetraoxa-1,4,7,13,16,18-hexaazatricyclo[17.5.5.57,13]tetratriacontane L is reported. Its basicity in aqueous solution has been investigated by potentiometric and spectroscopic (1H, 13C NMR) techniques. The basicity constants have been determined (25 °C, I= 0.15 mol dm–3) in two ionic media. Macrotricycle L behaves as a hexaprotic base: log K1= 10.27(3), log K2= 9.52(3), log K3= 7.12(3), log K4= 4.62(3), log K5= 2.80(3), log K6= 2.27(3) in NaClO4 and log K1= 10.09(3), log K2= 9.27(3), log K3= 6.54(3), log K4= 4.88(3), log K5= 3.75(3), log K6= 3.07(3) in NaCl. The constants relative to the equilibrium Cl–+ HnLn+⇌ HnLCl(n–1)+ have been measured: n= 5, log K= 2.48(3); n= 6, log K= 3.59(3). The crystal structure of L has been determined by single-crystal X-ray analysis. The compound crystallizes in a triclinic unit cell (space group P, Z= 2) with lattice constants a= 8.984(5), b= 12.122(2), c= 14.667(3)A, α= 109.52(2), β= 105.47(3), γ= 95.24(3)°. Least-squares refinement converged at R= 0.088 (R′= 0.075) for 3198 unique reflections with I > 4σ(I). The structure shows that the molecule has a skewed cylindrical shape, the bases being formed by the two N2O2 macrocycles with the N(CH2CH2)2 chains constituting the walls. The cylindrane L binds two Li+ ions and the resulting complex has been studied by 7Li NMR spectroscopy. Copper(II) and cadmium(II) complexes with L have been investigated in aqueous solution and their stability constants determined by potentiometric techniques. For both metals the following species have been found: [ML]2+, [MLH]3+, [ML(OH)]+ and [ML(OH)2].

The reaction between 2-substituted ethyl 2,5-dihydro-5-oxoisoxazole-4-carboxylates (2a,b) and heterocyclic amines 1, 4, and 6, having the amino group in position 2 with respect to the nuclear nitrogen afforded fused pyrimidines 3, 5, and 7.

The synthesis and the spectroscopic characterization of a new potential drug for urinary incontinence, adosupine, is described. Adosupine and its potential synthesis impurities were analyzed by a new HPLC method that was developed with a C18 reversed-phase column. The analysis was made under isocratic conditions, with a mobile phase of acetonitrile:water (15:85, v/v). Resolution of all synthesis impurities was allowed. The method was also applied to stability studies of adosupine in solid state and in solution under different conditions. With the conditions used, only one degradation product was shown by HPLC analysis; it was isolated, characterized, and identified as the hydrolysis product of the lactam ring present in the adosupine structure.

The reaction between ketones 1, amine hydrochlorides 2, and potassium isocyanoacetate (3) affords a series of dipeptide derivatives 5. The structure of compounds 5 is in agreement with their spectral data and is confirmed by means of X-ray analysis of 5a

The reaction between ethyl (Z)-3-dimethylamino-2-isocyanoacrylate (1) and arenesulfenyl chlorides (6a-c) afforded the unexpected imidazolyl- oxazolones (7a-c). The structure of compounds (7a-c) was in agreement with their 1 H nmr, ir and ms data and was confirmed by X-ray analysis of (7a)

The title compounds afforded under relatively mild conditions the polycyclic systems 3a, 4, and 5 through alternative concomitant cycloadditions; the reactivity of the dicyanopyridazine system was critically influenced by the presence of methyl groups at the 3 and 6 positions. The skeleton of 3a and the stereochemistry of 5 were established by X-ray experiments.

The title compound 4 reacted as a dienophile with open-chain and cyclic carbodienes as well as the 1-azadiene 16, to yield different polynuclear isoxazole systems. On the contrary, it gave rise preferentially to a Michael-type reaction with the dimethyluracil derivative 19 affording the cine-substitution product 23, whose structure was determined by an X-ray analysis. Some mechanistic features and synthetic opportunities are emphasized.

The reaction between cyanoacetic acid 1 and isocyanides 2 afforded the unexpected N,N’-disubstituted 2cyanoacetoxy-2-cyanomethylmalondiamides 3 which were easily cleaved in very mild conditions to the corresponding 2-hydroxy derivatives 4. The structure of compound 4a was confirmed by X-ray analysis. A hypothesis for the mechanism of formation of compounds 3 is presented.

The solid state conformation of the title compound was determined. Conformational analysis based on molecular modelling mechanics allowed the calculation of the energy of the most stable conformers and their comparison with X-ray conformation.

The Ugi four-component condensation between cycloalkanones, isocyanides, and ammonium formate affords N-substituted 1-formylamino-1-cycloalkanecarboxamides 1 which are dehydrated to give the corresponding isocyanides 2. Compounds 2 are cyclized with arylsulfenyl thiocyanates to 1,3-diazaspiro-2-thiones 4 and 5. A series of 1,3-diazaspiro[4,5]dec-1-en-4-ones 7 is prepared by cyclizing 2c–j with butyllithium. The structures of these compounds are confirmed by means of IR, 1H-NMR, and X-ray analysis.

The reaction between (Z)-methyl 3-dimethylamino-2-isocyanoacrylate (1a) and acyl chlorides 2a,b did not afford methyl 2-acyl-1-methyl-1H-imidazole-4-carboxylates 3a,b, as previously reported, but 2-acyl-4-dimeth-ylaminomethyleneoxazol-5(4H)-ones 4a,b.