Mátyás Czugler

Asymmetric C–C bond forming reactions with chiral crown catalysts derived from d-glucose and d-galactose

Abstract New chiral monoaza-15-crown-5 derivatives anellated to methyl-4,6-O-benzylidene-α- d -glucopyranoside 2a, 2e, 2g–i and to methyl-4,6-O-benzylidene-α- d -galactopyranoside 3a, 3e, 3i have been synthesized. These crown ethers showed significant asymmetric induction as phase transfer catalysts in the Michael addition of 2-nitropropane to chalcone (87% ee), in the Darzens condensation of phenacyl chloride with benzaldehyde (71% ee) and in the self-condensation of phenacyl chloride (64% ee) to give 14. The absolute configurations of (−)-(2R,3S)-epoxy-3-(4-chlorophenyl)-1-phenyl-1-propanone 12 and (−)-4-chloro-(2R,3S)-epoxy-1,3-diphenyl-1-butanone 14 have also been determined by X-ray diffraction.

New trigonal lattice hosts: stoicheiometric crystal inclusions of laterally trisubstituted benzenes—X-ray crystal structure of 1,3,5-tris-(4-carboxyphenyl)benzene·dimethylformamide

New host molecules with a central 1,3,5-trisubstituted benzene ring and rigidly attached lateral arms composed of aryl or arylethynyl and extra functional groups are reported. They are shown to give more than thirty clathrates with a wide variety of organic solvents comprising alicyclic, aromatic, heterocyclic, dipolar aprotic, and protic molecules. Inclusion selectivities and stoicheiometries of the different clathrates are discussed. The crystal structure of (2a)·dimethylformamide (DMF)(1:3) inclusion compound has been determined from single-crystal X-ray diffraction. The crystals show R symmetry. There are six host and eighteen guest molecules in the hexagonal unit cell with a=b= 23.160(9) and c= 11.812(3)A. The final linear R is 0.082 for 1 518 unique reflections. The host molecules adopts a propeller conformation with perfect three-fold symmetry and acts as a donor in hydrogen bonds to three DMF molecules. In the crystal structure the host–guest units are arranged stack-wise.

Functional group assisted clathrate formation — Scissor-like and roof-shaped host molecules

A strategy has been developed for the design, synthesis, and testing of new clathrate hosts that possess relationship complementarity to specific guest-compounds.

Enantioselective Michael reaction of 2-nitropropane with substituted chalcones catalysed by chiral azacrown ethers derived from α-D-glucose

Abstract The chiral monoaza-15-crown-5 lariat ethers anellated to methyl-4,6-O-benzylidene-α- d -glucopyranoside 1a–c showed significant asymmetric induction as phase transfer catalysts in the Michael addition of 2-nitropropane to substituted chalcones. Among the catalysts bearing different side arms at the nitrogen atom, the compound with a phosphinoxidoalkyl side chain 1c proved to be the most effective (max. 78% e.e.). The type of substituent on the chalcone was found to have a very significant influence on both the chemical yield and the enantioselectivity of the reaction. The absolute configuration of the Michael adducts 3b and 3i was determined by chemical methods, while that of 3d was assigned by X-ray crystal structure determination.

Double Diastereocontrol in Bifunctional Thiourea Organocatalysis: Iterative Michael–Michael–Henry Sequence Regulated by the Configuration of Chiral Catalysts

The importance and reactivity consequences of the double diastereocontrol in noncovalent bifunctional organocatalysis were studied. The results suggest that the bifunctional thioureas can have synthetic limitations in multicomponent domino or autotandem catalysis. Nevertheless, we provided a means to exploit this behavior and used the configuration of the chiral catalyst as a control element in organo-sequential reactions.

Enantioselective Michael addition of 2-nitropropane to chalcone analogues catalyzed by chiral azacrown ethers based on α-d-glucose and d-mannitol

Abstract The chiral monoaza-15-crown-5 type lariat ethers 1 and 2 derived from α- d -glucose and from d -mannitol, respectively, have been applied as phase transfer catalysts in the enantioselective Michael addition of 2-nitropropane to aromatic 3b–c and heteroaromatic 3d–h chalcone analogues. Among the catalysts, the glucose-based 1c with a phosphinoxidobutyl side arm proved to be the most effective, it inducing 34% e.e. for 4b, 59% e.e. for 4c, 80% e.e. for 4d, 64% e.e. for 4e, 17% e.e. for 4f. Catalyst 1a having 3-hydroxypropyl substituent resulted in 81% e.e. for compound 4g. The formation of the (+)-(S)-enantiomer of 4 was preferred using crown ethers 1a–c, while the (−)-(R)-enantiomer was in excess with catalyst 2. The absolute configuration of the Michael adduct 4d was determined by single-crystal X-ray analysis.

Comparison of theophyllinato Cu(II) complexes of ethanolamine and diethanolamine. Part 2. Structure and thermal study of the dimeric complex with diethanolamine

Abstract There is now much evidence that anticancer drugs exert biological action by preferred binding of a transition metal to the N7 sites of the guanine residues of DNA. In our series of theophyllinato copper(II) complexes containing amine ligands, the structural effect of changing from ethanolamine to diethanolamine is examined. A new mixed ligand copper(II) complex, bis(μ-2-(2-hydroxyethyl)aminoethanolato-O,N,O′)bis(theophyllinato-N7)dicopper(II) (C22H34N10O8Cu2) (1) has been synthesized as model compound from aqueous solutions of CuSO4, theophylline, and diethanolamine (dea). Its distinct Me2L2L′2 structure has been determined by single crystal X-ray diffraction. The centrosymmetric binuclear complex contains two strongly distorted square pyramidally (or pseudooctahedrally) coordinated copper ions bound together by two alkoxo-bridges. The bridging O is a deprotonated oxygen of the monoalcoholate formed from diethanolamine. Both of the theophyllinate anions take part in N7/O6 chelation in the complex 1, while only one of the theophyllinate anions is able to perform it in the mononuclear complex (SPY-5-12)-(2-aminoethanol-N)(2-aminoethanol-N,O)bis(theophyllinato-N7)copper(II) dihydrate (2). The two copper(II) centres in 1 are found to be antiferromagnetically coupled. The combined thermogravimetric and evolved gas detection shows that the tridentate alcoholate anions are fragmented and evolved between 125 and 275°C, whilst the degradation of theophyllinate anions begins at 350°C. Structural, spectroscopic and thermal comparison to the previously published analogous monoethanolamine Cu(II) complex (2) is presented.

Synthesis and resolution of naphthyl-Tröger's base

Abstract A naphthyl analogue of Trogers base {8 H ,16 H -7,15-methanodinaphtho[2,1- b ][2′,1′- f ][1,5]-diazocine (NTB)} was prepared and successfully resolved using (−)- and (+)-di- p -toluoyl-tartaric acid. Enantiomers obtained show extremely high specific rotations related to (i) the rigid [1,5]-diazocine skeleton with molecular asymmetry and (ii) the presence of condensed aromatic rings, similar to helicenes.

Intramolecular sulphur—oxygen interaction in organosulphur compounds with different sulphur valence state: an X-ray study of methyl-2-nitrobenzene-sulphenate, -sulphinate, -sulphonate and 2-nitrobenzenesulphenyl chloride

Abstract Molecular structures of methyl-2-nitrobenzenesulphenate, methyl-2-nitrobenzenesulphinate, methyl-2-nitrobenzenesulphonate and 2-nitrobenzenesulphenyl chloride have been determined by X-ray diffraction. The remarkably short S⋯O (nitro) distances (2.458, 2.743, 2.956 and 2.379/2.408 A) found in the almost linear XS⋯O sequences are controlled characteristically by both the valence state of sulphur and the electronegativity of the X counter-atom (X = OMe, O, OMe and Cl, respectively). The structure of the sulphonate is compared with that of the analogous sulphonyl chloride and conformations around the S(VI)C ar bonds are discussed. In the crystal lattice of 2-nitrobenzenesulphenyl chloride, intermolecular S⋯Cl close contacts of two different types (3.447 and 3.452 A) were observed. The differences in the geometries of adjacent molecules may be associated with these interactions.

The Effect of HCl on the Copper(II) Chloride/Pyridine/Water System: Synthesis, Properties and Crystal Structure of [(pyH)2CuCl4] and [(pyH)2Cu3Cl8(H2O)2]n

Bis(pyridinium) tetrachlorocuprate monomer 1 and bis(pyridinium) octachlorodiaquatricuprate polymer 2 were synthesized and their crystal structures were determined. Both complexes contain pyridinium cations with bifurcated H-bridges. These H-bridges stabilize the monomeric structure of the tetrachlorocuprate anion together with the steric demand of the relatively large pyridinium ions in the crystal lattice of 1. Conversely, at the lower pyridinium ion:copper(II) ratio of 2, the bifurcated hydrogen bonds reduce the electron density on the chloride ions in such a way that the electron repulsion decreases and coordination spheres with more ligand interactions develop. Obviously, water may be a successful competitor for ligand sites in 2 as well. The octahedral and square-pyramidal structural units condense into polymeric chains which are stabilized by the interchain hydrogen bond networks of the water molecules. The structure motif of SP-5-[OC-6-SP-5-SP-5]-OC-6 (−CuCl5-[CuCl4(OH2)2-CuCl5CuCl5]-CuCl4(OH2)2-) were observed in 2, and the two neighboring square-pyramidal units were found to be localized in a transoid position. The IR and ESR spectroscopical characterization of complexes was also performed.