37493-14-4Relevant articles and documents
Direct Organocatalytic Asymmetric α-Chlorination of Aldehydes
Halland, Nis,Braunton, Alan,Bachmann, Stephan,Marigo, Mauro,Jorgensen, Karl Anker
, p. 4790 - 4791 (2007/10/03)
The direct organocatalytic enantioselective α-chlorination of aldehydes has been developed. The reaction proceeds for a series of different aldehydes with NCS as the chlorine source using easily available catalysts such as L-proline amide and (2R,5R)-diphenylpyrrolidine. The α-chloro aldehydes are obtained in up to 99% yield and up to 95% ee. The synthetic utility of the enantioselective α-chlorination of aldehydes is demonstrated by transformation of the α-chloro aldehydes to the corresponding α-chloro alcohols (>90% yield) by standard reduction and further transformation to both a terminal epoxide and amino alcohol, both obtained without loss of optical purity. Oxidation of the α-chloro aldehydes followed by esterification gave optically active α-chloro esters without loss of optical purity. It is demonstrated that these optically active α-chloro esters can be converted into nonproteinogenic amino acids in overall high yields, maintaining the enantiomeric excess obtained in the catalytic enantioselective α-chlorination step. Copyright
SYNTHESIS OF LIQUID CRYSTALS CONTAINING CHLORINE ON THE CHIRAL CENTER
Fodor-Csorba, K.,Vajda, A.,Bata, L.,Holly, S.,Gacs-Baitz, E.,et al.
, p. 97 - 110 (2007/10/02)
A synthetic pathway is described for the preparation of the homologous series of (R)-(2-chloropropyl)-4-benzoates with high optical purity.The liquid crystalline members of the series exhibit smectic A phase and can be used as chiral dopants in ferroelectric mixtures.The n=8 member was used in a mixture exhibiting monotropic and the n=9 member enantiotropic smectic C* phase around room temperature.
Chiral Mesogenic Compounds: Carbocyclic and Heterocyclic Schiff Bases
Barbera, J.,Melendez, E.,Serrano, J. L.,Sierra, M. T.,Ezcurra, A.,Jubindo, M. A. Perez
, p. 151 - 158 (2007/10/02)
Five different chiral p-substituted anilines derived from 4-aminobenzoic acid and from 4-aminophenol were condensed with four carbocyclic and heterocyclic aldehydes in order to obtain chiral Schiff bases resembling DOBAMBC and HOBACPC.With the exception of the pyridine-3-carboxaldehyde derivatives, the compounds are mesomorphic.Some of the compounds exhibit ferroelectric SC* phases, and all exhibit SA or Ch mesophases on heating.Benzaldehyde and pyridine-2-carboxaldehyde derivatives show similar mesomorphic behavior, as was to be expected from MNDO semiempirical calculations.Values of the spontaneous polarization of certain compounds were measured.
