Supramolecular Isomerism and Isomorphism in the Structures of 1,4-Butanebisphosphonic Acid and Its Organic Ammonium Salts

1,4-Butanebisphosphonic acid crystallizes as two concomitant polymorphs, a triclinic phase (1a) and an orthorhombic phase (1b), both comprising pillared-layered hydrogen-bonded networks and exhibiting supramolecular isomerism. Two organic salts of this acid with aniline (2) and p-phenylazoaniline (3) were synthesized and characterized by X-ray diffraction analysis. Compounds 2 and 3 show supramolecular isomorphism with pillared-bilayered frameworks. Our results demonstrate the potential use of bisphosphonic acids for the synthesis of new solid materials

An Approach toward the Triquinane-Type Skeleton via Reagent-Controlled Skeletal Rearrangements. A Facile Method for Protection−Deprotection of Organomercurials, Tuning the Selectivity of Wagner−Meerwein Migrations, and a New Route to Annulated Lactones^†

Nonlinear triquinane-type building blocks have been synthesized using three strategic steps, namely, (1) Hg2+-mediated opening of a cyclopropane ring involving a skeletal rearrangement (3 → 8), (2) an intramolecular organometallic addition across a CO bond triggered by activation of the C−HgX group by means of Me3CuLi2 (14 → 26), and (3) selective, reagent-controlled skeletal rearrangements (43 → 47 with Tl3+ or Hg2+; 43 → 51 + 52 with Pd2+; 44 → 47 with Pd2+). A new method for protection/deprotection of organomercurials has been developed, which allows selective reduction of a carbonyl group with NaBH4 and other hydrides (8 → 14 → 16 → 20) and Tebbe methylenation (14 → 31 → 32). Oxidative demercuration (8 → 11 + 28) and Pd2+-catalyzed carbonylation of organomercurials (20 → 53) allowed syntheses of γ- and δ-lactones

PINDY: A Novel, Pinene-Derived Bipyridine Ligand and Its Application in Asymmetric, Copper(I)-Catalyzed Allylic Oxidation^†

The title bipyridine ligand (+)-6(PINDY), prepared in five steps from (−)-β-pinene, forms a stable complex with CuCl2 (8) that has been characterized by X-ray crystallography to reveal an unusual geometry at Cu. Triflate 9 proved to catalyze asymmetric allylic oxidation (10 → 11; rt, ∼30 min, 49−75% ee)

Synthesis and Structure of Silver Complexes with Nicotinate-Type Ligands Having Antibacterial Activities against Clinically Isolated Antibiotic Resistant Pathogens

The synthesis and low-temperature X-ray crystal structures of five new silver complexes, [Ag2-μ-O,O‘(2-aminonicotinium)2(NO3)2]n (7), [Ag(isonicotinamide)2-μ-O,O‘(NO3)]2 (8), [Ag(ethyl nicotinate)2](NO3) (9), [Ag(ethyl isonicotinate)2(NO3)] (10), and [Ag(methyl isonicotinate)2(H2O)](NO3) (11), are presented and fully characterized by spectral and elemental analysis. The antimicrobial activities of these complexes were screened using 12 different clinical isolates belonging to four pathogenic bacteria, S. aureus, S. pyogenes, P. mirabilis, and Ps. Aeruginosa, all obtained from diabetic foot ulcers. These tested bacteria were resistant for at least 10 antibiotics commonly used for treatment of diabetic foot ulcers. Compounds 7 and 8 had considerable activity against Ps. Aeruginosa (MIC values 2−8 μg/mL), compound 9 against S. aureus (MIC 4−16 μg/mL) and S. pyogenes (MIC 2−4 μg/mL), and also 9 and 11 against P. mirabilis (MIC 1−16 μg/mL). All complexes were non-toxic for daphnia at concentrations above 512 μg/mL overnight

Chiral 2,2‘-Bipyridine-Type <i>N</i>-Monoxides as Organocatalysts in the Enantioselective Allylation of Aldehydes with Allyltrichlorosilane^†

The Sakurai−Hosomi-type allylation of aromatic and heteroaromatic aldehydes can be catalyzed by the new heterobidenate bipyridine monoxide PINDOX with high enantioselectivities. The sterochemical outcome is mainly controlled by the axial chirality in PINDOX, which in turn is determined by the annulated terpene units

Synthesis and Structure of Silver Complexes with Nicotinate-Type Ligands Having Antibacterial Activities against Clinically Isolated Antibiotic Resistant Pathogens

The synthesis and low-temperature X-ray crystal structures of five new silver complexes, [Ag2-μ-O,O‘(2-aminonicotinium)2(NO3)2]n (7), [Ag(isonicotinamide)2-μ-O,O‘(NO3)]2 (8), [Ag(ethyl nicotinate)2](NO3) (9), [Ag(ethyl isonicotinate)2(NO3)] (10), and [Ag(methyl isonicotinate)2(H2O)](NO3) (11), are presented and fully characterized by spectral and elemental analysis. The antimicrobial activities of these complexes were screened using 12 different clinical isolates belonging to four pathogenic bacteria, S. aureus, S. pyogenes, P. mirabilis, and Ps. Aeruginosa, all obtained from diabetic foot ulcers. These tested bacteria were resistant for at least 10 antibiotics commonly used for treatment of diabetic foot ulcers. Compounds 7 and 8 had considerable activity against Ps. Aeruginosa (MIC values 2−8 μg/mL), compound 9 against S. aureus (MIC 4−16 μg/mL) and S. pyogenes (MIC 2−4 μg/mL), and also 9 and 11 against P. mirabilis (MIC 1−16 μg/mL). All complexes were non-toxic for daphnia at concentrations above 512 μg/mL overnight

Chiral 2,2‘-Bipyridine-Type <i>N</i>-Monoxides as Organocatalysts in the Enantioselective Allylation of Aldehydes with Allyltrichlorosilane^†

The Sakurai−Hosomi-type allylation of aromatic and heteroaromatic aldehydes can be catalyzed by the new heterobidenate bipyridine monoxide PINDOX with high enantioselectivities. The sterochemical outcome is mainly controlled by the axial chirality in PINDOX, which in turn is determined by the annulated terpene units

Synthesis of New Chiral 2,2‘-Bipyridyl-Type Ligands, Their Coordination to Molybdenum(0), Copper(II), and Palladium(II), and Application in Asymmetric Allylic Substitution, Allylic Oxidation, and Cyclopropanation

A series of chiral bipyridine-type ligands 5−12 has been synthesized via a de novo construction of the pyridine nucleus. The chiral moieties of the ligands originate from the monoterpene realm, namely, pinocarvone (13 → 6, 7, and 9), myrtenal (18 → 5), nopinone (21 → 8 and 10), and menthone (28 → 11 and 12); the first three precursors can be obtained in one step from β- and α-pinene, respectively. Complexes of these ligands with molybdenum(0) (38−40) and copper(II) (41) have been characterized by single-crystal X-ray crystallography. While complex 38 exhibits polymorphism (monoclinic and tetragonal forms crystallize from the same batch), 41 is characterized by a tetrahedrally distorted geometry of the metal coordination. The Mo and Pd complexes exhibit modest asymmetric induction in allylic substitution (43 → 44), and the Cu(I) counterpart of 41, derived from 10 (PINDY) and Cu(OTf)2, shows promising enantioselectivity (49−75% ee) and reaction rate (≥30 min at room temperature) in allylic oxidation of cyclic olefins (47 → 48). The Cu(I) complex of 11 (MINDY) proved effective in cyclopropanation (49 → 50) with up to 72% ee

Family of Isoreticular Chiral Metal−Organic Frameworks Based on Coordination and Hydrogen Bonds in [M[Co(ethylenediamine)(oxalato)₂]₂]

From the parent compound [Ca[Co(ethylenediamine)(oxalato)2]2]n·4H2O, 1, a series of framework compounds was prepared via the soluble sodium salt and crystal growth with the divalent metal ions Cd2+, Mn2+, and Sr2+, (2−4). These compounds have the same general formula [M[Co(ethylenediamine)(oxalato)2]2]n·xH2O, and they all form the same four- and eight-connected 3D net having scu topology (and are thus isoreticular) with water filled channels of variable size running in one direction of the crystals. However, they crystallize in two different space groups, the chiral P21 (3, 4, and the low temperature form of 1) and the noncentrosymmetric P4̅ (1 and 2). The potential voids upon water removal are 18−20% of the unit cell. Preliminary gas sorption measurements at 298 K and 8 bar show substantial CO2 and N2O uptake (12−14% and 15−16% by mass, respectively), while the H2 uptake was 0.18%, a relatively high value considering the low pressure and high temperature

Copper(II)-Mediated Oxidative Coupling of 2-Aminonaphthalene Homologues. Competition between the Straight Dimerization and the Formation of Carbazoles^◊

Whereas the Cu(II)-mediated oxidative coupling of 2-aminonaphthalenes 7a and 7b results in the clean formation of 1,1‘-binaphthyls 13a and 13b, respectively, their higher homologues and congeners 8−12 have been found to exhibit a different reaction pattern. Thus, 2-aminoanthracene (8) gave a ∼1:1 mixture of the expected bianthryl derivative 15 and the carbazole 16, whereas the 9-aminophenanthrene (10), 3-phenyl-1-aminonaphthalene (11), and 2-aminochrysene (12) produced almost exclusively the corresponding carbazoles 19, 20, and 21, respectively. By contrast, the isomeric 3-aminophenanthrene (9) gave rise to the azo compound 17 as a result of the preferential oxidation on the nitrogen. The carbazoles have been shown to arise directly from the coupling reactions rather than from the primarily formed binaphthyls. Alternatively, carbazole 19 can also be prepared from 1b on reaction with hydrazine. On the other hand, treatment of 3a with hydrazine resulted in the formation of a ∼2:7 mixture of amine 11 and arylhydrazine 22. 2,2‘-Diamino-1,1‘-bianthryl (15) has been resolved into enantiomers via cocrystallization with (−)-N-benzylcinchonidinium chloride and shown to have (R)-(−)-15 configuration by X-ray crystallography