Corrado Malanga

Selective Mono- or Dialkoxylation of 2,4,6-Trichloro-1,3,5-triazine in Solid-Liquid Phase Transfer Conditions

Abstract In solid-liquid phase transfer conditions, both the primary and the secondary alcohols react cleanly with 2,4, 6-trichloro-1,3,5-triazine to give the corresponding mono or dialkoxy derivatives depending on the reagent molar ratio.

Direct ni mediated synthesis of ketones from acyl bromides and grignard reagents

Abstract a catalytic amount of NidppeCl 2 converts an acyl bromide directly into ketones at 0 °C in THF in the presence of a Grignard reagent. The described procedure represents a useful way to afford dialkyl, diaryl or alkyl aryl ketones as well as 1,2-diketones. In the adopted reaction conditions double bonds, esters and ketones are unaffected.

Carbon-halogen bond activation by nickel catalyst: Synthesis of alkenes, from 1,2-dihalides

Abstract Unsaturated hydrocarbons can easily be prepared in a few seconds starting from 1,2 dibromides in the presence of a catalytic amount of Nickel diphenylphosphinoethane dichloride (NidppeCl2) and tri.n.butyl tin hydride, (TBTH) at room temperature. The dependencie of the nature of starting dihalides is investigated.

2,5-Dimethoxy-2,5-dihydrofuran and vinyl ethers in the synthesis of functionalised 2-alkylfurans

Abstract 2,5-Dimethoxy-2,5-dihydrofuran reacts, in the presence of a catalytic amount of MgBr 2 ·Et 2 O with the appropriate vinyl ether, to give functionalised 2-alkylfurans with good yield and mild reaction conditions, this represents a useful synthetic approach to 2-(2-furo)tetrahydro -furanic or -pyranic moieties. The reaction fails on using deactivated or α-substituted vinyl ethers.

Selective Amination of Cyanuric Chloride in the Presence of 18‐Crown‐6

An interpretation of the role of 18-crown-6 in the selective di- and trialkylamination of 2,4,6-trichloro-1,3,5-triazine is reported, and the usefulness of the procedure is shown. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

(η6-Naphthalene)(η4-cycloocta-1,5-diene)ruthenium(0) as efficient catalytic precursor for the isomerization of methyl linoleate under mild conditions

Abstract The Ru(η6-naphthalene)(η4-cycloocta-1,5-diene) complex, 1, in the presence of acetonitrile, is able to promote the isomerization of methyl linoleate under mild conditions (60°C) with high yields. Using aprotic solvents (hexane) the reaction is very selective, by-products like methyl oleates and polymers are formed in negligible amounts. A remarkable long-lived catalytic activity has been observed.

Nickel Mediated Conversion of Acyl Halides in Aldehydes

Abstract Aldehydes are obtained from acyl halides employing stoichiometric tri n.butyl tin hydride (TBTH) and catalytic nickeldiphenylphosphinoethane dichloride (NidppeCl 2 ), at room temperature.

NICKEL MEDIATED FLASH ISOMERIZATION - A NEW APPROACH TO 1,4-BUT-1-ENE DIOL DERIVATIVES

Abstract Fast isomerization of cis 1,4-but-2-endiol derivatives ( 1 ) to 1,4-but-1-endiol derivatives ( 2 ) was carried out in mild conditions. The activity of the proposed Ni-hydride species is closely correlated with the nature of the protecting groups of the alcoholic functions of 1 , which are also responsible for the regio and stereo chemical aspects of the reaction.

A new approach to δ-lactones, related to the Prelog-Djerassi lactone.

Abstract The reductive rearrangement of 2-ethoxy-5-(2-alkenyl)-2H-tetrahydropyrane systems, in the presence of AlBu13, was used as the key-step in the synthesis of Prelog-Djerassi related lactones.

From the SmA to the Hexatic, Including the SmC*, SmC*A and SmC*re Phases: A 2H NMR Relaxation Study

The molecular dynamics of a ferroelectric liquid crystal, denoted ZLL 7/*, is investigated by means of (2)H NMR relaxation. The spin-lattice (T(1Q) and T(1Z)) and spin-spin (T(2)) relaxation times of two isotopomers of ZLL 7/*, labeled on the phenyl and biphenyl fragments, are measured and their behavior upon passing from the SmA to the hexatic phase, through the ferroelectric SmC*, antiferroelectric SmC*(A), and re-entrant ferroelectric SmC*(re) phases, is discussed. A comparison between the measured T(2) and T(2)*, directly related to the experimental linewidth, provides information on the heterogeneity of the system, thus allowing confirmation of previous hypotheses concerning the structural and ordering properties of the SmC*(A) and SmC*(re) phases. The possibility to look at different sites of the core of the ZLL 7/* smectogen reveals a peculiar sensitivity of the phenyl moiety with respect to the biphenyl fragment, which may be justified by its vicinity to the chiral centers. Interestingly, the trend of the longitudinal relaxation times is characterized by a minimum that corresponds to the SmC*(A) and SmC*(re) phases, which is reproducible for the two isotopomers and at several Larmor frequencies. A quantitative analysis of T(1Q) and T(1Z) is performed in the SmA and SmC* phases, for which the narrowing regime approximation is valid. A multifrequency approach is applied to self-consistently determine the diffusion coefficients for the overall molecular motions, namely spinning and tumbling, and the internal rotations around the para axes of the phenyl and biphenyl fragments. The effect of the magnetic field in unwinding the helical structure of the SmC* phase (for H>9 T) allows observation of a sensitive change in the rotational diffusion coefficients in the frustrated unwound SmC* phase with respect to the SmC* phase.