- New copper(II) 2-(alkylamino)troponates
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The copper aminotropones Cu[ON(R′)C7H4R-4] 2 [R = H, R′ = Me (13), Et (14), n-Pr (15), n-Bu (16), Bz (17), MenOCH2CH2 (20); R = i-Pr, R′ = Me (18), n-Pr (19), MenOCH2CH2 (21)] have been prepared from the corresponding aminotropones HN(R′)OC7H4R-4 (1-7) by reacting with copper(II) acetate in aqueous ethanol. 20, 21 contain the flavourant, menthol, as part of the ligand. The structures of 5 (R = H, R′ = Bz), a hydrogen-bonded dimer, 14 and 20, both incorporating square-planar, four-coordinate copper centres, have been determined by X-ray crystallography. The antibacterial activities of complexes 13, 17, 20 and 21 have been assayed against Staphylococcus waneri, an in vitro model of plaque inhibition effects, and found to be more active than a commercial toothpaste formulation, but less active than the O,O-chelated copper(II) complex of ethylmaltol.
- Barret, Marie C.,Bhatia, Purvi H.,Kociok-Koehn, Gabriele,Molloy, Kieran C.
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p. 543 - 551
(2014/08/05)
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- Synthesis, structure, and properties of chiral liquid crystal monomers and polymers based on menthol
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To study structure-mesomorphism relationships of the monomers and polymers based on menthol, four new chiral monomers (M1-M4) and the corresponding homopolymers (P1-P4) with menthyl group were synthesized. Their chemical structures, formula, phase behavior, and thermal stability were characterized by FTIR, 1H NMR, 13C NMR, elemental analyses, differential scanning calorimetry, polarizing optical microscopy, X-ray diffraction, and thermogravimetric analysis. The selective reflection of light was investigated with ultraviolet/visible spectrometer. The influence of the mesogenic core rigidity, spacer length, and menthyl steric effect on the mesomorphism of M1-M4 and P 1-P4 was examined. By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, four target monomers and polymers could form the expected mesophase. Moreover, their melting temperature (Tm), glass transition temperature (Tg), clearing temperature (Ti), and mesophase range (δT) increased with increasing the mesogenic core rigidity; whereas the Tm and T g decreased, Ti and δT increased with an increase of the spacer length. M1 and M2 showed monotropic and enantiotropic cholesteric phase, respectively, whereas M3 and M 4 all revealed chiral smectic C (SmC*), cholesteric and cubic blue phases. In addition, with increasing temperature, the selective reflection of light shifted to the long wavelength region at the SmC* phase range and to the short wavelength region at the cholesteric range, respectively. P 1 and P2 only showed a smectic A (SmA) phase, whereas P3 and P4 exhibited the SmC* and SmA phases. All the obtained polymers had very good thermal stability.
- Hu, Jian-She,Li, Dan,Zhang, Wen-Chang,Meng, Qing-Bao
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p. 5049 - 5059
(2013/01/15)
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- Chemical resolution of (±)-calanolide A, (±)-cordatolide A and their 11-demethyl analogues
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The chemical resolution of (±)-calanolide A and (±)-cordatolide A into their corresponding optically active enantiomers is described. Their inhibitory activities against HIV-1 are tested in vitro.
- Ma, Tao,Gao, Qi,Chen, Zhiwei,Wang, Lin,Liu, Gang
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p. 1079 - 1083
(2008/12/20)
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- Diastereomeric reissert compounds of isoquinoline and 6,7-dimethoxy-3,4- dihydroisoquinoline in stereoselective synthesis
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(Chemical Equation Presented) Chiral acid chlorides were reacted with isoquinoline and 6,7-dimethoxy-3,4-dihydroisoquinoline to form diastereomeric Reissert compounds 8-11 and 18-21, respectively. The best diastereoselectivity (80:20) was achieved in formation of the 9-phenylmenthyl derivative 20. The diastereomers of 2-l-menthoxy-carbonyl-1,2-dihydroisoquinaldonitriles (S)-8/(R)-8), formed in equal amounts, were inseparable. However, the individual diastereomers of 2-cholesteryloxycarbonyl-1,2-dihydroisoquinaldonitriles ((R)-11 and (5)-11) and the 2-l-menthoxycarbonyl-6,7-dimethoxy-1,2,3,4- tetrahydroisoquinaldonitriles ((S)-19/(R)-19)) were each readily purified. (S)-8/(R)-8 (1:1) via the corresponding anions (NaH, -40°C, DMF) with pivaldehyde yielded in 82:18 predominance the S-diastereomer of 1-isoquinolyl tert-butyl carbinyl l-menthyl carbonate ((S)-12), which was obtained in pure form by a single recrystallization; hydrolysis produced 99% pure S-(-)-1-isoquinolyl tert-butyl carbinol [(S)-16]. Reactions of the anions of diastereomeric Reissert compounds, either as mixtures or pure single species, with aromatic aldehydes and alkyl halides proceeded with at best modest selectivity (diastereomeric ratios up to 66:34 and 72:28, respectively). Therefore, it is concluded that the Reissert anions are either planar or rapidly inverting tetrahedral structures.
- Gibson, Harry W.,Berg, Michael A. G.,Dickson, Jennifer Clifton,Lecavalier, Pierre R.,Wang, Hong,Merola, Joseph S.
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p. 5759 - 5770
(2008/02/11)
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- Asymmetric catalysis; 140:1 tris(2-pyridyl)methane derivatives with a chiral bridging atom
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Two different series of C1-symmetric tris(2-pyridyl)methane tripod ligands were synthesized with pyridin-2-yl, 6-phenylpyridin-2-yl and 6-methoxy- or 6-menthyloxypyridin-2-yl substitutents. The menthoxy devivatives were resolved with respect to
- Brunner,Maier,Zabel
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p. 2484 - 2494
(2007/10/03)
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- First attempts at differential diastereoselection in catalytic reactions of N-chirally substituted dirhodium(II) tetrakis[methyl 2-oxoimidazolidine-4(S)-carboxylates] with diazoacetates
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Chiral attachments on 2-oxoimidazolidine-4(S)-carboxylate ligands for dirhodium(II) can provide differential diastereoselection in catalytic reactions of diazo compounds. The synthesis of these heterocyclic ligands from the readily available amino acid as
- Doyle,Timmons,Arndt,Duursma,Colyer,Bruenner
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p. 2156 - 2161
(2007/10/03)
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- The synthesis of 1-O-(2-N-stearoyl-D-erythro-sphinganine-1-phosphoryl)-2-O-(α-D-mannopyranosyl-D-myo-inositol: a fragment of the naturally occurring inositol-containing glycophosphosphingolipids
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Chiral mannosylinositol containing sphingophospholipid was synthesized from D-erythro ceramide and optically active mannosyl-myo-inositol with the use of phosphite triester coupling procedure.The optical resolution of racemic 3,4,5,6-tetra-O-benzyl-myo-in
- Zamyatina, Alla Yu.,Shvets, Vitaliy I.
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p. 225 - 240
(2007/10/02)
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- Mikrobial Oxidation in Synthesis: Preparation of (+)- and (-)-Pinitol from Benzene
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Microbial oxidation with Pseudomonas putida of benzene affords cis-1,2-dihydroxycyclohexa-3,5-diene (2) which may be converted in five steps and 49percent overall yield to (+/-)-pinitol.Resolution of an intermediate alcohol (6) with menthoxyacetyl chloride provides optically pure materials which may be independently transformed to (+)- or (-)-pinitol.Demethylation conditions for pinitol together with further reactions of (2) and related compounds were investigated.
- Ley, Steven V.,Sternfeld, Francine
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p. 3463 - 3476
(2007/10/02)
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- Synthesis of Monocyclic β-Lactams with a Terpenoid Moiety
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A series of new monocyclic β-lactams with a terpenoid moiety have been prepared by reaction of schiff bases with appropriate terpenyl acid chlorides in the presence of triethylamine.Their structural assignments are based on elemental analyses and spectral
- Varma, R. Luxmi,Narayanan, C. S.
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p. 302 - 304
(2007/10/02)
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