Synthesis of γ-hydroxypropyl P-chirogenic (±)-phosphorus oxide derivatives by regioselective ring-opening of oxaphospholane 2-oxide precursors

The synthesis of P-chirogenic (±)-phosphine oxides and phosphinates via selective nucleophilic ring opening of the corresponding oxaphospholanes is described. Two representative substrates: the phosphonate 2-ethoxy-1,2-oxaphospholane 2-oxide and the phosphinate 2-phenyl-1,2-oxaphospholane 2-oxide were reacted with various Grignard reagents to produce a single alkyl/aryl product. These products may possess further functionalities in addition to the phosphorus center such as the γ-hydroxypropyl group which results from the ring opening and π-donor moieties such as aryl, allyl, propargyl and allene which originates from the Grignard reagent.

Crystal structure of 1-[2-(2,6-dichlorophenyl)-4,5-diphenyl-1H-imidazol-1-yl]propan-2-ol

The central imidazole ring of the title compound, C24H20Cl2N2O, is twisted with respect to with the planes of the 2,6-dichlorobenzene and two phenyl rings, making dihedral angles of 74.06 (18), 28.52 (17) and 67.65 (18)°, respectively. The phenyl ring not adjacent to the N-bonded 2-hydroxypropyl group shows the greatest twist, presumably to minimize steric interactions. In the crystal, molecules are linked by O—H...N and C—H...O hydrogen-bond contacts into chains along thea-axis direction. The series of parallel chains form a two-dimensional sheet approximately parallel to thebcdiagonal. In addition, C—H...π interactions are observed between the sheets. The atoms of the 2-hydroxypropyl group and the N atom of the 1H-imidazole ring to which it is bonded are disordered over two sets of sites, with an occupancy ratio of 0.722 (5):0.278 (5). The structure was refined as an inversion twin.

Crystal structure of 4-[1-(2-hydroxypropyl)-4,5-diphenyl-1H-imidazol-2-yl]benzoic acid

In the title compound, C25H22N2O3, the central imidazole ring makes dihedral angles of 48.43 (10), 20.23 (10) and 75.38 (11)° with the benzene ring and the two phenyl rings, respectively. The phenyl ring adjacent to the N-bonded 2-hydroxypropyl group shows the greatest twist, presumably to minimize steric interactions. In the crystal, molecules are linked by O—H...N, O—H...O and C—H...O hydrogen bonds, forming a three-dimensional network. In addition, C—H...π interactions are also observed.

Synthese flexibler difluorierter cyclopropanoider Nucleosidanaloga / Synthesis of Flexible Difluorinated Cyclopropanoid Nucleoside Analogues

A novel class of difluorinated cyclopropanoic nucleoside analogues containing a hydroxypropyl group and a methylene spacer between the difluorocyclopropane ring and the heterocycle has been prepared.