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1.  (2SR,3SR)-Isopropyl 3-{[dimeth­yl(phenyl)­sil­yl]meth­yl}-2-hy­droxy-2-vinyl­pent-4-enoate 
The relative configuration of the title compound, C19H28O3Si, which was synthesized using a dienolate-[2,3]-Wittig rearrangement, was corroborated by single-crystal X-ray diffraction analysis. The Si—C bond distances are in the range 1.858 (2)–1.880 (2) Å and an intra­molecular O—H⋯O hydrogen bond helps to stabilize the mol­ecular conformation.
doi:10.1107/S1600536810044818
PMCID: PMC3011670  PMID: 21589408
2.  (3R,4R,5S)-4-Hydr­oxy-3-methyl-5-[(2S,3R)-3-methyl­pent-4-en-2-yl]-4,5-dihydro­furan-2(3H)-one 
The relative configuration of the title compound, C11H18O3, which was synthesized using a catalytic asymmetric Gosteli–Claisen rearrangement, a diastereoselective reduction with K-Selectride and an Evans aldol addition, was corroborated by single-crystal X-ray diffraction analysis. The five-membered ring has an envelope conformation with a dihedral angle of 29.46 (16)° between the coplanar part and the flap (the hydr­oxy-bearing ring C atom). In the crystal, mol­ecules are connected via bifurcated O—H⋯(O,O) hydrogen bonds, generating [010] chains.
doi:10.1107/S1600536809050399
PMCID: PMC2971977  PMID: 21578968
3.  7,7-Dimethyl-4a-(3-methyl-2-buten­yl)-2-oxo-4a,5,6,7-tetra­hydro-2H-chromen-4-yl benzoate 
An intra­molecular Claisen-like cyclization of ethyl 2-acet­oxy-4,4-dimethyl-1-(3-methyl­but-2-en­yl)cyclo­hex-2-enecarboxylate followed by dialkyl­ation yielded the bicyclic title compound, C23H26O4. In both of the fused six-membered rings exist fragments of four atoms which are planar, whereas the remaining two atoms deviate by up to 0.682 (3) Å on one side of the plane of the ring containing an O atom and by up to 0.415 (3) Å on opposite sides of the other ring. The dihedral anglebetween the planar fragments of the six-membered rings is 41.76 (10)°
doi:10.1107/S1600536809030918
PMCID: PMC2970087  PMID: 21577549
4.  7,7-Dimethyl-3,3,4a-tris­(3-methyl­but-2-en­yl)-4a,5,6,7-tetra­hydro-2H-chromene-2,4(3H)-dione 
The title compound, C26H38O3, was prepared by an intra­molecular Claisen-like cyclization of ethyl 2-acet­oxy-4,4-dimethyl-1-(3-methyl­but-2-en­yl)cyclo­hex-2-enecarboxyl­ate followed by dialkyl­ation. One of the methyl groups is disordered over two sets of sites in a 0.67:0.33 ratio.
doi:10.1107/S1600536809025021
PMCID: PMC2977115  PMID: 21583462
5.  (±)-syn-Isopropyl 4-(1,1,1,3,3,3-hexa­fluoro­propan-2-yl­oxy)-1-hydr­oxy-3-methyl-2-(prop-1-yn­yl)cyclo­pent-2-ene­carboxyl­ate 
The title compound, C16H18F6O4, was obtained through an unprecedented one-pot reaction sequence involving a Gosteli–Claisen rearrangement and a cyclo­isomerization. The constitution and relative configuration were determined by single-crystal X-ray diffraction analysis. In the crystal, mol­ecules are connected via O—H ⋯ O hydrogen bonds.
doi:10.1107/S1600536809023162
PMCID: PMC2969198  PMID: 21582922
6.  {2,2-Bis[(4S)-4-tert-butyl-4,5-dihydro-1,3-oxazol-2-yl]propane}bis­(N,N-di­methyl­formamide)copper(II) bis­(hexa­fluoridoantimonate) 
In the title compound, [Cu(C17H30N2O2)(C3H7NO)2][SbF6]2, which is a potential catalyst in the asymmetric Gosteli–Claisen rearrangement, the Cu atom adopts a distorted cis-CuN2O2 square-planar geometry arising from N,N′-bidentate coordin­ation by the chiral ligand and two O-bonded dimethyl­formamide mol­ecules. Two short C—H⋯O contacts occur within the ligand and two weak inter­molecular C—H⋯F bonds may help to establish the packing.
doi:10.1107/S1600536809020364
PMCID: PMC2969361  PMID: 21582678
7.  (3S,4S,5S)-4-Hydr­oxy-3-methyl-5-[(2S,3R)-3-methyl­pent-4-en-2-yl]-4,5-dihydro­furan-2(3H)-one 
The title compound, C11H18O3, was synthesized to prove the relative configuration of the corresponding acyclic C1—C8 stereopentade. Mol­ecules are linked via O—H⋯O hydrogen bonds, forming a chain along the b axis.
doi:10.1107/S1600536808026998
PMCID: PMC2960667  PMID: 21201808
8.  (3R,4S,5S)-4-Hydr­oxy-3-methyl-5-[(2S,3R)-3-methyl­pent-4-en-2-yl]tetra­hydro­furan-2-one 
The title compound, C11H18O3, was synthesized to prove the relative configuration of the corresponding acyclic C1—C8 stereopentade. It crystallizes with two mol­ecules in the asymmetric unit, which show only slight differences. The mol­ecules are linked via O—H⋯O hydrogen bonds, resulting in two crystallographically independent chains of mol­ecules propagating in the a-axis direction. The absolute configuration was known from the synthesis.
doi:10.1107/S1600536808021181
PMCID: PMC2962143  PMID: 21203225
9.  (1R,4′S)-4-(tert-Butyl­dimethyl­silan­oxy)-1-[2,2-dimethyl-3-(p-tolyl­sulfon­yl)-1,3-oxazolidin-4-yl]but-2-yn-1-ol 
The chiral title compound, C22H35NO5SSi, is a precursor of novel furan­omycin derivatives. It crystallizes with two molecules in the asymmetric unit; these show different conformations of the silyl substitutent, as indicated by the Si—O—C—C torsion angles of 41.4 (7) and −84.5 (5)° in the two mol­ecules. The anti configuration of the adjacent stereogenic centers is consistent with the Felkin–Anh model. Each of the two crystallographically independent mol­ecules is connected with a neighbouring mol­ecule of the same type via two symmetry-equivalent O—H⋯O hydrogen bonds.
doi:10.1107/S1600536808014906
PMCID: PMC2961448  PMID: 21202678
10.  Communication: Synthesis of a Novel Triphenyltin(IV) Derivative of 2- Mercaptonicotinic Acid with Potent Cytotoxicity in vitro  
A novel triphenyltin(IV) derivative of 2-mercaptonicotinic acid (H2mna) of formula {[(C6H5)3Sn]2(mna).[(CH3)2CO]} (1) has been synthesized and characterized by elemental analysis and 1H, 13C-NMR, and FT-IR spectroscopic techniques. The crystal structure of complex (1) has been determined by single crystal X-ray diffraction analysis at 173(1) K. Compound (1) contains two triphenyltin moieties linked by a doubly de-protonated 2,mercaptonicotinic acid (H>2mna). It is an example of a pentacoordinated Ph3SnXY system with an axial-equatorial arrangement of the phenyl groups at Sn(1). Compound (1), exhibits potent, in vitro, cytotoxicity against sarcoma cancer cells (mesenchymal tissue) from the Wistar rat, polycyclic aromatic hydrocarbons (PAH, benzo[a]pyrene) carcinogenesis.
doi:10.1155/S1565363303000189
PMCID: PMC2267064  PMID: 18365056

Results 1-10 (10)