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1.
Racemic 1,1′-methylene[(1RS,1′RS,3RS,3′RS,5RS,5′RS)-8-oxabicyclo[3.2.1]oct-6-en-3-ol] ((±)-6) derived from 2,2′-methylenedifuran has been resolved kinetically with Candida cyclindracea lipase-catalysed transesterification giving 1,1′-methylenedi[(1R,1′R,3R,3′R,5R,5′R)-8-oxabicyclo[3.2.1]oct-6-en-3-ol] (−)-6 (30% yield, 98% ee) and 1,1′-methylenedi[(1S,1′S,3S,3′S,5S,5′S)-8-oxabicyclo[3.2.1]oct-6-en-3-yl] diacetate (+)-8, (40% yield, 98% ee). These compounds have been converted into 1,1′-methylenedi[(4S,4′S,6S,6′S)- and (4R,4′R,6R,6′R)-cyclohept-1-en-4,6-diyl] derivatives.  相似文献   

2.
Acid-catalyzed condensation of (+)-mollisacacidin-[(2R, 3S, 4R)-2, 3-trans-3, 4-trans-flavan-3,3′,4,4′,7-pentaol] with an excess of (−)-robinetinidol[(2R,3S)-2,3-trans-flavan-3,3′,4′,5′,7-pentaol] afforded a novel series of bi-, tri-, and tetraflavanoid profisetinidins. They are accompanied by (−)-fisetinidol-(4,2′)-(−)-robinetinidol which results from the pyrogallol B-ring of (−)-robinetinidol serving as nucleophile competing with its resorcinol A-ring in coupling with a C-4 carbocationic intermediate. Similar condensation with (+)-epifisetinidol[(2S,3S)-2,3-cis-flavan-3,3′,4′,7-tetraol] led to the exclusive formation of [4,6]-interflavanyl bonds, these units being ‘linearly’ arranged in the tetraflavanoid analogue in contrast to the ‘branched’ nature of the (−)-robinetinidol homologue.  相似文献   

3.
Three spiro[pyrrolidine-2,3′-oxindoles], 1,1′,2,2′,5′,6′,7′,7′a-octahydro-2-oxo-1′-phenyl-spiro[3H-indole-3,3′-[3H]-pyrrolizine]-2′-carboxylic acid methyl ester (1), 1,1′,2,2′,5′,6′,7′,7′a-octahydro-2-oxo-1′-nitro-2′-phenyl-spiro[3H-indole-3, 3′-[3H]-pyrrolizine] (2) and 1,1′,2,2′,5′,6′,7′,7′a-octahydro-2-oxo-1′-nitro-2′-(4″-chlorophenyl)-spiro[3H-indole-3,3′-[3H]-pyrrolizine] (3) have been synthesized and their 1H, 13C and 15N spectra assigned. The chemical shift assignments are based on Pulsed Field Gradient (PFG) Double Quantum Filter (DQF) 1H, 1H correlation spectroscopy (COSY), PFG 1H, 13C Heteronuclear Multiple Quantum Coherence (HMQC) and PFG 1H,X (X = 13C and 15N) Heteronuclear Multiple Bond Correlation (HMBC) experiments. The single crystal X-ray structures of 1–3 have been determined. Compounds 1 and 2 crystallized in monoclinic space group C2/c and compound 3 in monoclinic space group P21/c, respectively. Also the ESI-TOF MS data of 1–3 are given.  相似文献   

4.
The enantiomers of Georgywood® were synthesized from (E)-2-methyl-6-methylene-nona-2,7-diene and methacrylaldehyde followed by oxidation of the Diels–Alder adduct and classical racemate separation of the acid with optically-active N-methylephedrine. Conversion to the final ketone and olfactory evaluation showed that the (−)-(1R,2S)-enantiomer is more powerful by a factor of >100 than its antipode. The absolute configuration was determined by conformational studies and CD-analysis.  相似文献   

5.
The chiral ligands, 4,4′-bis{(1S,2R,4S)-(−)-bornyloxy}-2,2′-bipyridine, (1S,2R,4S)-1, and 4,4′-bis{(1R,2S,4R)-(+)-bornyloxy}-2,2′-bipyridine, (1R,2S,4R)-1, have been prepared and characterized by spectroscopic techniques and, for (1S,2R,4S)-1, by single crystal X-ray diffraction. Despite the use of enantiomerically pure ligands, the formation of the complexes [Fe((1S,2R,4S)-1)3]2+, [Ru((1S,2R,4S)-1)3]2+, [Ru((1S,2R,4S)-1)(bpy)2]2+ and [Ru((1R,2S,4R)-1)(bpy)2]2+ proceeds without preference for either the Δ or Λ-diastereoisomers.  相似文献   

6.
The crystal and molecular structures of 2′-amino-6′-dibutylamino-3′-methylspiro[isobenzofuran-1(3H), 9′[9H]xanthen]-3-one (1), 2′-amino-6′-(N-cyclohexyl-N-methylamino)-3′-methylspiro[isobenzofuran-1(3H), 9′[9H]xanthen]-3-one (2) and 2′-(2-chlorophenyl)amino-6′-dibutylaminospiro[isobenzofuran-1(3H), 9′[9H]xanthen-3-one (3) have been determined by single-crystal X-ray diffraction analysis. Atom-atom non-bonded potential energy and semiempirical quantum chemical calculations have been performed. The xanthene rings of 1 to 3 are slightly bent and the phthalide rings are planar. The phthalide ring moieties are almost perpendicular (88.9(1)−93.5(5)°) to the xanthene rings. The bond lengths C(6)---O(2) are apparently extended from the normal C(sp3)---O (lactone) length. The temperature factors for one butyl group C(32)---C(35)) of 1 increase gradually toward the terminal carbon. The temperature factors for C(30)---C(33) of 2 indicate large vibrations and these are reflected in short bond lengths. Two butyl groups of 3 are disordered and these C---C bond lengths are short and long alternately. Atomic net charges around spirocarbon C(6) and toward N(1) to C(6) indicate the weak alternative system in the colorless form. As the xanthene ring has a planar geometry, the π electron density migration will easily occur from the auxochromes attached to the phthalide ring to the xanthene ring.  相似文献   

7.
The crystal and molecular structures of 2′-amino-6′-dibutylamino-3′-methylspiro[isobenzofuran-1(3H), 9′[9H]xanthen]-3-one (1), 2′-amino-6′-(N-cyclohexyl-N-methylamino)-3′-methylspiro[isobenzofuran-1(3H), 9′[9H]xanthen]-3-one (2) and 2′-(2-chlorophenyl)amino-6′-dibutylaminospiro[isobenzofuran-1(3H), 9′[9H]xanthen-3-one (3) have been determined by single-crystal X-ray diffraction analysis. Atom-atom non-bonded potential energy and semiempirical quantum chemical calculations have been performed. The xanthene rings of 1 to 3 are slightly bent and the phthalide rings are planar. The phthalide ring moieties are almost perpendicular (88.9(1)–93.5(5)°) to the xanthene rings. The bond lengths C(6)---O(2) are apparently extended from the normal C(sp3---O (lactone) length. The temperature factors for one butyl group C(32)---C(35)) of 1 increase gradually toward the terminal carbon. The temperature factors for C(30)---C(33) of 2 indicate large vibrations and these are reflected in short bond lengths. Two butyl groups of 3 are disordered and these C---C bond lengths are short and long alternately. Atomic net charges around spirocarbon C(6) and toward N(1) to C(6) indicate the weak alternative system in the colorless form. As the xanthene ring has a planar geometry, the π electron density migration will easily occur from the auxochromes attached to the phthalide ring to the xanthene ring.  相似文献   

8.
(1R,2R,3R,7aR)-1,2-Dihydroxy-3-hydroxymethylpyrrolizidine (+)-Hyacinthacine A2 1 has been synthesized by Wittig's methodology using [(2′S,3′R,4′R,5′R)-3′,4′-dibenzyloxy-N-tert-butyloxycarbonyl-5′-tert-butyldiphenylsilyloxymethylpyrrolidin-2′-yl]carbaldehyde 3, prepared from a partially protected DMDP 2, and the appropriated ylide, followed by cyclization by an internal reductive amination process of the resulting unsaturated aldehyde 4 and total deprotection.  相似文献   

9.
(+)-Carpamic acid [(2′R,5′S,6′S)-8-(5′-hydroxy-6′-methylpiperidin-2′-yl)octanoic acid, 1] was synthesized from (S)-alanine, employing intramolecular and reductive amination of acyclic amino ketone 8 as the key step to generate the piperidine ring.  相似文献   

10.
Methods of synthesis of new chiral amino ether derivatives through the opening of aziridinium ions, prepared in situ using trans-(±)-2-(1-N,N-dialkylamino)cyclohexyl mesylate with (R)-(+)-1,1′-bi-2-naphthol, are described. The (R,R,R)-diastereomer was obtained as the major product and isolated as an enantiopure salt, and characterized by single crystal X-ray analysis. The C2-chiral (R,R,R,R,R)-diamino ether was obtained as the major product by opening of the aziridinium ion, prepared using trans-(±)-2-(1-pyrrolidino)cyclohexyl mesylate and (R)-(+)-1,1′-bi-2-naphthol in the presence of aq NaOH. This was also characterized by single crystal X-ray analysis.  相似文献   

11.
1-Pentene has been polymerized in the presence of deuterium using as catalyst precursors [Al(CH3)-O]n and (−)-ethylenebis(4,5,6,7-tetrahydro)-(R)-1-indenylzirconium derivatives ((−)-(R)-EBTHI-ZrX2, X = CH3 (I); X = (R)-1′,1″-bi-2-naphtholate (II)). The investigation of 1,2-dideuteriopentane and of the deuteriooligomers thus obtained shows that the (Re) enantioface of the olefin is predominantly involved in the deuteration but its (Si) enantioface in the dimerization and oligomerization. These results, which show the participation of the growing chain in the enantioface discrimination in the stereospecific polymerization of 1-pentene are discussed on the basis of a simple stereochemical model for the transition state of the olefin insertion step.  相似文献   

12.
6,6′-Bis(1H, 1H, 2H, 2H-perfluorooctyl)-1, 1′-bi-2-naphthol (Rf6-BINOL) and 6,6′-bis(1H, 1H, 2H, 2H-perfluorodecyl)-1,1′-bi-2-naphthol (Rf8-BINOL) were used in allylation of aldehydes in fluorous biphase system. Good enantioselectivity was obtained and the ligands could be recovered by continuos liquid–liquid extraction.  相似文献   

13.
The coordination of 1,5-bis-(1′-phenyl-3′-methyl-5′-pyrazolone-4′)-1,5-pentanedione (BPMPPD) and 2,2′-bipyridine (bipy) with lanthanide ions in water-alcohol solution has been studied. Binuclear complexes of the types : Ln2(BPMPPD)3(bipy)2·nH2O (n = 2 for Y, n = 4 for Eu, Gd, Dy, Ho, Er, Tm and Yb); Ln2(BPMPPD)3bipy·nH2O (n = 10 for La, n = 3 for Pr, Nd, Sm and Tb) were formed. The compounds were characterized by elemental analysis, molar conductance, IR, UV, 1H NMR spectroscopy, thermogravimetric analysis and fluorescence spectra.  相似文献   

14.
The antipodes of 1-aryl-, 1-alkyl- and 1-alkoxy-3-methyl-3-phospholene 1-oxides 1a–h and 1-phenyl-3-methyl-3-phospholene 1-sulfide 1i were separated in good yields and high enantiomeric excesses (up to >99% ee) by resolution via formation of diastereomeric complexes with either (−)-(4R,5R)-4,5-bis(diphenylhydroxymethyl)-2,2-dimethyldioxolane 2 (TADDOL) or (−)-(2R,3R)-,,′,′-tetraphenyl-1,4-dioxaspiro[4.5]decan-2,3-dimethanol 3. The stereostructure of the supramolecular formations and the absolute configurations of the 3-phospholene oxides 1a, 1e and 1f were elucidated by single crystal X-ray crystallography. CD spectroscopy was also useful in determining the absolute configurations of some phospholene oxides 1b, 1c, 1g and 1h.  相似文献   

15.
N-2-(4-picolyl)-N′-2-chlorophenylthiourea, 4PicTu2Cl, monoclinic, P21/c, a=10.068(5), b=11.715(2), β=96.88(4)°, and Z=4; N-2-(6-picolyl)-N′-2-chlorophenylthiourea, 6PicTu2Cl, triclinic, P-1, a=7.4250(8), b=7.5690(16), c=12.664(3) Å, =105.706(17), β=103.181(13), γ=90.063(13)°, V=665.6(2) Å3 and Z=2 and N-2-(6-picolyl)-N′-2-bromophenylthiourea, 6PicTu2Br, triclinic, P-1, a=7.512(4), b=7.535(6), c=12.575(4) Å, a=103.14(3), β=105.67(3), γ=90.28(4)°, V=665.7(2) Å3 and Z=2. The intramolecular hydrogen bonding between N′H and the pyridine nitrogen and intermolecular hydrogen bonding involving the thione sulfur and the NH hydrogen, as well as the planarity of the molecules, are affected by the position of the methyl substituent on the pyridine ring. The enthalpies of fusion and melting points of these thioureas are also affected. 1H NMR studies in CDCl3 show the NH′ hydrogen resonance considerably downfield from other resonances in their spectra.  相似文献   

16.
The course of the intramolecular meta photocycloaddition of ring-substituted (E)- and (Z)- 6-phenylhex-2-enes depends on the position and nature of the substituent. In this paper, the effects of methyl and cyano groups and the fluorine atom are described. The results are in agreement with a reaction mechanism in which the excited phenyl ring becomes polarized when it is approached by the alkene. The dipolar character becomes particularly apparent in the case of fluorine which, depending on its position, can stabilize either the negative charge through its inductive effect or the positive charge through its mesomeric effect. The configuration of the terminal methyl group sterically influences the photoreaction. The Z alkenes readily undergo the 1′,3′-addition, but fail to add in the 2′,6′-mode, even if substituents which strongly promote this mode are present. The E alkenes seem to suffer from steric hindrance in the 2′,6′- and the 1′,3′-mode, but the electronic effects of activating substituents provide compensation and substituents may have a pronounced influence on the ratio of the two modes.  相似文献   

17.
Structures of the following compounds have been obtained: N-(2-pyridyl)-N′-2-thiomethoxyphenylthiourea, PyTu2SMe, monoclinic, P21/c, a=11.905(3), b=4.7660(8), c=23,532(6) Å, β=95.993(8)°, V=1327.9(5) Å3 and Z=4; N-2-(3-picolyl)-N′-2-thiomethoxyphenyl-thiourea, 3PicTu2SeMe, monoclinic, C2/c, a=22.870(5), b=7.564(1), c=16.941(4) Å, β=98.300(6)°, V=2899.9(9) Å3 and Z=8; N-2-(4-picolyl)-N′-2-thiomethoxyphenylthiourea, 4PicTu2SMe, monoclinic P21/a, a=9.44(5), b=18.18(7), c=8.376(12) Å, β=91.62(5)°, V=1437(1) Å3 and Z=4; N-2-(5-picolyl)-N′-2-thiomethoxyphenylthiourea, 5PicTu2SMe, monoclinic, C2/c, a=21.807(2), b=7.5940(9), c=17.500(2) Å, β=93.267(6)°, V=2893.3(5) Å3 and Z=8; N-2-(6-picolyl)-N′-2-thiomethoxyphenylthiourea, 6PicTu2SMe, monoclinic, P21/c, a=8.499(4), b=7.819(2), c=22.291(8) Å, β=90.73(3)°, V=1481.2(9) Å3 and Z=4 and N-2-(4,6-lutidyl)-N′-2-thiomethoxyphenyl-thiourea, 4,6LutTu2SMe, monoclinic, P21/c, a=11.621(1), b=9.324(1), c=14.604(1) Å, β=96.378(4)°, V=1572.4(2) Å3 and Z=4. Comparisons with other N-2-pyridyl-N′-arylthioureas having substituents in the 2-position of the aryl ring are included.  相似文献   

18.
The enantioselective hydrolysis of (3RS,4RS)-trans-4-(4′-fluorophenyl)-6-oxo-piperidin-3-ethyl carboxylate (±)-2 was effected using a commercial preparation of lipase from C. antarctica A (CAL-A). We found that the hydrolytic activity of the lipase (immobilized on a number of very different supports) with this substrate was negligible. However, a contaminant esterase with Mw of 52 KDa from this commercial preparation exhibited much higher activity with (±)-2. This enzyme was purified and immobilized on PEI-coated support and the resulting enzyme preparation was highly enantioselective in the hydrolysis of (±)-2 (E >100), hydrolyzing only the (3S,4R)-(−)-3, which is a useful intermediate for the synthesis of pharmaceutically important (−)-paroxetine. Optimization of the reaction system was performed using a racemic mixture with a substrate concentration of 50 mM. This enzyme preparation was used in three reaction cycles and maintained its catalytic properties.  相似文献   

19.
The “naked sugar” (+)-(1R,2R,4R)-2-cyano-7-oxabicyclo[2.2.1]hept-5-en-2-exo-yl acetate ((+)-3) was converted in ten synthetic steps into the new C-nucleoside (1R)-1-C-(6′-amino-7′H-purin-8′-yl)-1,4-anhydro-3-azido-2,3-dideoxy- D-erythro-pentitol ((+)-2) in 19% overall yield.  相似文献   

20.
The photolysis of 2,2′-dinitrodiphenylmethylbenzoates (1a–1d) in 2-propanol gives dibenzo-[c, f]-[1,2]diazepin-11-one-oxides (5a–5d) as the major product. Dibenzo[c, f]-[1,2]diazepin-11-ones (2a–2d), 2,2′-dinitrobenzophenones (3a–3d), 2-amino-2′-nitrobenzophenones (4a–4d) and N-hydroxyacridones (6a–6d) are also formed in the reaction. When the irradiation is carried out in benzene, 3-(2′-nitrophenyl)-2,1-benzisoxazoles (7a–7d) are also obtained together with the above products.  相似文献   

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