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1.
The isolation and structure elucidation of the 17-membered macrocyclic spermine alkaloids (−)-(S)-verbasitrine ( 2 ), (−)-(S)-isoverbasitrine ( 4 ), (+)-(S)-verbametrine ( 6 ), and (+)-(S)-isoverbametrine ( 8 ) is presented. The synthesis of their racemates is described.  相似文献   

2.
The template reaction of {bis[(S)-2-(aminomethyl)pyrrolidine]}copper(II) with formaldehyde, nitroethane, and base in MeOH yields optically pure {1,7-bis[(S)-pyrrolidin-2-yl]-4-methyl-4-nitro-2,6-diazaheptane}- copper(II) ([Cu((S,S)-mnppm)]2+) in high yield. The same reaction with rac-2-(aminomethyl)pyrrolidine is also described. Preparative details and spectroscopic and electrochemical properties of the CuII complexes and of the free ligands are reported and compared with structural, spectroscopic and electrochemical data of the CuII complex of the unsubstituted parent ligand 1,7-bis[(S)-pyrrolidin-2-yl]-2,6-diazaheptane (ppm). The crystal structure of [Cu(ppm)]Cl ClO4 has been determined by X-ray diffraction methods.  相似文献   

3.
Asymmetric syntheses of the following 17‐membered macrocyclic spermine alkaloids are presented: (−)‐(S)‐protoverbine (=(8S)‐8‐phenyl‐1,5,9,13‐tetraazacycloheptadecane‐6‐one; 1 ), (+)‐(S)‐protomethine (=(2S)‐2‐phenyl‐1,5,9,14‐tetraazabicyclo[12.3.1]octadecan‐4‐one; 2 ), (−)‐(S)‐buchnerine (=(8S)‐8‐(4‐methoxyphenyl)‐1,5,9,13‐tetraazacycloheptadecane‐6‐one; 8 ), (+)‐(S)‐verbamethine (=(+)‐(2S)‐9‐[(E)‐phenylprop‐2‐enoyl]‐2‐phenyl‐1,5,9,14‐tetraazabicyclo[12.3.1]octadecan‐4‐one; 4 ), (−)‐(S)‐verbacine (=(−)‐(8S)‐1‐[(E)‐phenylprop‐2‐enoyl]‐8‐phenyl‐1,5,9,13‐tetraazacycloheptadecan‐6‐one; 3 ), (−)‐(S)‐verbasikrine (=(−)‐(8S)‐1‐[(E)‐3‐(4‐methoxyphenyl)prop‐2‐enoyl]‐8‐phenyl‐1,5,9,13‐tetraazacycloheptadecan‐6‐one; 26 ), (−)‐(S)‐isoverbasikrine (=(−)‐(8S)‐1‐[(Z)‐3‐(4‐methoxyphenyl)prop‐2‐enoyl]‐8‐phenyl‐1,5,9,13‐tetraazacycloheptadecan‐6‐one; 25 ), (+)‐(S)‐verbamekrine (=(+)‐(2S)‐9‐[(E)‐3‐(4‐methoxyphenyl)prop‐2‐enoyl]‐2‐phenyl‐1,5,9,14‐tetraazabicyclo[12.3.1]octadecan‐4‐one; 23 ), and (+)‐(S)‐isoverbamekrine (=(+)‐(2S)‐9‐[(Z)‐3‐(4‐methoxyphenyl)prop‐2‐enoyl]‐2‐phenyl‐1,5,9,14‐tetraazabicyclo[12.3.1]octadecan‐4‐one; 24 ). Effective methods for 1H‐NMR determination of the enantiomeric purity in which (S)‐2‐hydroxy‐2‐phenylacetic acid and (S)‐2‐acetoxy‐2‐phenylacetic acid are used as shift reagents for 1, 8 , and related macrocyclic alkaloids are described.  相似文献   

4.
Starting from (R)-3-hydroxybutyric acid ((R)- 10 ) the C45- and C50-carotenoids (all-E,2S,2′S)-bacterioruberm ( 1 ), (all-E,2S,2′S)-monoanhydrobacterioruberin ( 2 ), (all-E,2S,2′S)-bisanhydrobacterioruberin ( 3 ), (all-E,2R,2′R)-3,4,3′,4′-tetrahydrobisanhydrobacterioruberin ( 5 ), and (all-E,S)-2-isopentenyl-3,4-dehydrorhodopin ( 6 ) were synthesized. By comparison of the chiroptical data of the natural and the synthetic compounds, the (2S)- and (2′S)-configuration of the natural products 1–3 and 6 was established.  相似文献   

5.
We have isolated from the carpophores of Boletus satanas Lenz (Basidiomycetae) (2S,4S)-(+)-γ-hydroxynorvaline ( 1 ) and (2S,4R)-(?)-γ-hydroxynorvaline ( 2 ). The chirality of each diastereomer has been determined by chemical synthesis starting from optically active precursors and by application of different chiroptical methods. Gaschromatographic separation of the derived diastereomeric N-[(S)-α-methoxypropionyl]-lactones reveals that the optical purity of natural 2 is 88% whereas 1 exists as a partial racemate: (2S,4S): (2R,4R) = 3:2. Muscarine could not be detected in the carpophores of B. satanas, contrary to some literature data but basic substances of unknown structure are present in low concentration.  相似文献   

6.
Colourless block‐shaped crystals of [(NH4)2(2.2.2‐cryptand)2][P2S8] ( 1 ) and [(NH4)2(18‐crown‐6)2][P2S8]·H2O ( 2 ) could be obtained by the reaction of an aqueous solution of ammonium hexathiohypodiphosphate, (NH4)4P2S6·2 H2O, with sulfur and 2.2.2‐cryptand or 18‐crown‐6. The crystal structures of both compounds have been determined by single‐crystal X‐Ray diffraction analysis. Compound 1 crystallizes in the monoclinic space group C2/c with a = 2032.7(2), b = 1243.6(2), c = 2244.6(2) pm, β = 98.64(1)°, and Z = 8, whereas compound 2 crystallizes also monoclinic in the space group P21/c with a = 2121.3(2), b = 865.5(1), c = 2345.4(2) pm, β = 91.96(1)°, and Z = 4. It could be established that the title compounds contain a new type of six‐membered [1,2‐P2S4] ring with P – P bond and three S – S linkages. The tetrahedral environment of each phosphorus is completed by a (formally) single and double bonded sulfur atom attached externally to the [1,2‐P2S4] ring. These terminal PS2 units are mesomerically stabilized according to their P – S distances. FT‐IR and FT‐Raman spectra of the title compounds are recorded and interpreted.  相似文献   

7.
The first total enantioselective synthesis of (+)-(4S, 8R)-8-epi-β-bisabolol(+)- 1 and of (?)-(4R, 8 S )-4-epi-β-bisabolol ((?))? 1 ) is reported. The key step in the synthesis is the kinetic resolution of (±)? 5 by means of the Sharpless epoxidation yielding (?)- and (+}? 6 , respectively. Reduction of the epoxides with LiAlH4 gave the diols (+)-and(?)? 7 which were transformed into (+)- and (?)? 8 , respectively, via the corresponding mesylate. Reaction of these epoxides with the Grignard reagent derived from homoprenylbromide, assisted by Li2CuCl4, finished the synthesis of the target compounds 1 with high diastereo- and enantioselectivity.  相似文献   

8.
Synthesis, crystal structure, thermal stability, and magnetic properties of mixed‐ligand complexes of cobalt(II) with ß‐diketonato (thd = C11H19O2?) and alkoxides (OR mainly OMe = methoxide = CH3O? or OEt = ethoxide = C2H5O?) are reported. Direct reaction between Co(thd)2 ( 1 ) and EtOH gives a new complex with the structural formula [Co4(thd)4(OEt)4] ( 2 ) whereas MeOH correspondingly reacts to [Co4(thd)4(OMe)4(MeOH)4] ( 3 ). The yield of these products decreases with increasing size of the R group owing to increased solubility of 1 in the alcohol. The structure of 2 is determined from single‐crystal X‐ray diffraction data. At 100 K 2 takes a monoclinic structure (space group C2/c): a = 15.108(2), b = 19.428(2), c = 21.240(3) Å, and β = 108.882(2)°. At 295 K 2 has transformed to a closely related orthorhombic structure (space group Fddd): a = 15.233(3), b = 19.712(3), c = 40.916(7) Å. Protracted hydrolysis accompanied by oxygenation of complexes 2 and 3 in laboratory air (viz. simultaneous exposure to moisture and oxygen) leads to a new complex 4 with empirical formula corresponding to [Co(thd)(OH)(O2)]. Magnetic susceptibility data show that Co takes the valence state II in all complexes 1 – 4 . For 4 this implies that dioxygen has to form an adduct‐like association to the rest of the complex. Unfortunately complex 4 has hitherto only been obtained in the amorphous state, but all here produced evidences point at 4 as a distinct entity and that products of 4 obtained from 2 and 3 are chemically identical (but differ somewhat with regard to short‐ and longer‐range order in the atomic arrangement). The interatomic distances in the crystal structure of complexes 1 – 3 are briefly discussed in terms of the bond‐valence concept.  相似文献   

9.
The reaction of Mo(0) complex [Mo(CO)4(S2CNEt2)]- with phenthiolate [Et4N]SΦ in acetonitrile in the presence of small amount of air affords a new oxo-molybdenum complex [MoO(SΦ)2(S2CNEt2)], which crystallizes in two forms of crystals. [Et4N][MoO(SΦ)2Φ(S2CNEt2)] (1a) and [Et4N][MoO(SΦ)2(S2CNEt2)]Φ(CH3)2CHOH (1b). The structures of 1a and 1b were determined from three-dimensional X-ray data. 1a crystallizes in the monoclinic, space group Ce with a=12.321(4), b=15.245(4), c=16.087(9)Å; β= 98.44(4)Φ, V=2989Å3, Z=4, Dc = 1.35g/cm3 and R=0.031 for 2434 reflections [I>36(I)]. 1b crystallizes in the monoclinic space group F21/n with a=9.861(1), b=20.357(3), c=17.122(5)Å; β= 92.27 (2)*, V=3434.3Å3, Z=4; De = 1.29g/cm3 and R= 0.051 for 2852 independent reflections [I>3σ(I)]. The structures of 1a and 1b reveal that the anion [MoO(SΦ)2(S2CNEt2)]- contains a single oxo ligand coordinating to a molybdenum(IV) and the geometry around Mo(IV) atom is a distorted square pyramid. Interestingly, the solvate molecule isopropanol of 1b is linked to oxo group by a hydrogen-bond of 1.928Å, leading to the increase of Mo?O bond distance (1.718Å). Mo—S distances are 2.44 and 2.39Å. The electrochemical behavior of 1 was discussed also.  相似文献   

10.
Novel Synthesis of (?)-(R)-Cembrene A, Synthesis of (+)-(R)-Cembrenene and (+)-(S)-Cembrene A novel synthesis of (?)-(R)-cembrene A ((?)- 3 ) was developed using the Sharpless epoxidation for the introduction of the chiral center. Furthermore, the synthesis of (+)-(R)-cembrenene ((+)- 4 ) showed that this cembranoid must have the (R)-configuration and not, as previously reported, the (S)-configuration. Selective hydrogenation of (+)- 4 afforded (+)-(S)-cenibrene ((+)- 5 ).  相似文献   

11.
Stereochemical Correlations between (2R,4′R,8′R)-α-Tocopherol, (25S,26)-Dihydroxycholecalciferol, (–)-(1S,5R)-Frontalin and (–)-(R)-Linalol The optically active C5- and C4-building units 1 and 2 with their hydroxy group at a asymmetric C-atom were transformed to (–)-(1S,5R)-Frontalin ( 7 ) and (–)-(3R)-Linalol ( 8 ) respectively; 1 and 2 had been used earlier in the preparation of the chroman part of (2R,4′R,8′R)-α-Tocopherol ( 6a , vitamin E), and for introduction of the side chain in (25S,26)-Dihydroxycholecalciferol ((25S)- 4 ), a natural metabolite of Vitamin D3. The stereochemical correlations resulting from these converions fit into a coherent picture with those correlations already known from literature and they confirm our earlier stereochemical assignments. A stereochemical assignment concerning the C(25)-epimers of 25,26-Dihydroxycholecalciferol that was in contrast to our findings and that initiated the conversion of 1 and 2 to 7 resp. 8 for additional stereochemical correlations has been corrected in the meantime by the authors [26].  相似文献   

12.
The synthesis, structure, and magnetic properties of four 2,2′‐dipyridylamine ligand (abbreviated as Hdpa) containing copper(II) complexes. There is one binuclear compound, which is [Cu21,1‐NCO)2(NCO)2(Hdpa)2] ( 1 ), and three mononuclear compounds, which are [Cu{N(CN)2}2(Hdpa)2] ( 2 ), [Cu(CH3CO2)(Hdpa)2·N(CN)2] ( 3 ), and [Cu(NCS)(Acac)] ( 4 ). Compounds 1 and 4 crystallize in the monoclinic system, space group P2(1)/c and Z = 4, with a = 8.2465(6) Å, b = 9.3059(7) Å, c = 16.0817(12) Å, β = 91.090(1)°, and V = 1233.90(16) Å3 for 1 and a = 7.6766(6) Å, b = 21.888(3) Å, c = 10.4678(12) Å, β = 90.301(2)°, and V= 1758.8(4) Å3 for 4 . Compounds 2 and 3 crystallize in the triclinic system, space group P‐1 and Z = 1, with a = 8.1140(3) Å, b = 8.2470(3) Å, c = 9.3120(4) Å, β = 102.2370(10)°, and V = 592.63(4) Å3 for 2 and a = 7.4780(2) Å, b = 12.5700(3) Å, c = 13.0450(3) Å, β = 96.351(2)°, and V = 1211.17(5) Å3 for 3 . Complex ( 1 ), the magnetic data was fitted by the Bleaney‐Bowers equation (1). A very good fit was derived with J = 23.96, Θ = ?1.5 (g = 1.97). Complex ( 1 ) shows the ferromagnetism. Complexes ( 2 ), ( 3 ) and ( 4 ) of have the it is the typical paramagnetic behavior of unpaired electrons. Under a low temperature around 25 K, complexes ( 2 ) and ( 3 ) show weak ferromagnetic behavior. They are the cause of hydrogen bonds.  相似文献   

13.
(+)-(S)-Streptenol A is synthesized by coupling a 1,3-dithiane with an optically pure epoxide. The absolute configuration of (+)-(S)-streptenol A is thereby correlated with that of (S)-malic acid. Stereoselective reduction of an oxime that could easily be prepared from streptenol A gave the (3S,5R)- and (3S,5S)-aminostreptenols, and after cyclization, configurationally pure 2,4-functionalized piperidine alkaloids.  相似文献   

14.
Synthesis of two naturally occurring macrocyclic lactones is described. (?)-(R)-Phoracantholide I ((?)- 1 ; Scheme 2) was synthesized by asymmetric and chemoselective reduction of the side-chain C?O group of (?)4-(1-nitro-2-oxocyclohexyl)butan-2-one ((?)- 6 ) with (R)-Alpine-Hydride (47% ee). It was shown that the formation of only one diastereoisomer of the hemiacetal 5 , by methylation with (i-PrO)2TiMe2 of ketoaldehyde (?)- 2 is thermodynamically controlled. (+)-(S)-Tetradecan-13-olide ((+)- 10 ) was obtained by reduction of diketone (±)- 11 with optically active borohydrides followed by denitration (Scheme 3).  相似文献   

15.
The reaction of oleum (65 % SO3) with the tetrachlorides of silicon, germanium, and titanium, respectively, led to the complex disulfates Sr2[M(S2O7)4] (M=Si, Ge), Ba[M(S2O7)3] (M=Si, Ge, Ti) and Pb[M(S2O7)3] (M=Ge, Ti) if strontium, barium, and lead were used as divalent counter cations. The strontium compounds exhibit the unique tetrakis‐(disulfato)‐metallate anions [M(S2O7)4]4? with the silicon and germanium atoms in octahedral coordination of two chelating and two monodentate disulfate groups. All of the other compounds display tris‐(disulfato)‐metallate anions [M(S2O7)3]2? with three chelating disulfate groups surrounding the M atoms. Thermoanalytical investigations on the germanium compounds Sr2[Ge(S2O7)4] and Ba[Ge(S2O7)3] revealed their decomposition in multi‐step processes leading to a mixture of BSO4 and BGe4O9 (B=Sr, Ba), while the thermal degradation of Pb[Ti(S2O7)3] yields PbTiO3. For selected examples, IR data are additionally presented.  相似文献   

16.
The (?)-(2S)-Diethyl 2-Hydroxyhexanedioate, a New Chiral Building Block for Enantioselective Synthesis (?)-(2S)-Diethyl 2-hydroxyhexanedioate ((2S)-3) has been obtained by enantioselective reduction of diethyl 2-oxohexanedioate ( 1 ) with baker's yeast. The key intermediate (?)-(5S)-ethyl 5,6-dihydroxyhexanoate ((5S)- 5 ) is proved to be a useful synthon for the synthesis of chiral δ-lactones and a precursor of leukotriene LTB4 ((5S)- 13 ).  相似文献   

17.
Synthesis of Optically Active Natural Carotenoids and Structurally Related Compounds. VIII. Synthesis of (3S,3′S)-7,8,7′,8′-Tetradehydroastaxanthin and (3S,3′S)-7,8-Didehydroastaxanthin (Asterinic Acid) The synthesis of all-trans-(3S,3′S)-3,3′-dihydroxy-7,8, 7′,8′-tetradehydro-β, β-carotene-4,4′-dione ( 1 ), of all-trans-(3S,3′S)-3,3′-dihydroxy-7, 8-didehydro-β,β-carotene-4,4′-dione ( 2 ) (asterinic acid = mixture of 1 and 2 ), and of their 9,9′-di-cis- and 9-cis-isomers is reported starting from (4′S)(2E)-5-(4′-hydroxy-2′, 6′,6′-trimethyl-3′-oxo-l′-cyclohexenyl)-3-methyl-2-penten-4-ynal ( 8 ). The absolute configuration (3S,3′S) for both components 1 and 2 of asterinic acid ex Asterias rubens is confirmed on the basis of spectroscopic and direct comparison.  相似文献   

18.
The compound 2‐[(4‐phenoxyphenyl)sulfonylmethyl]thiirane, C15H14O3S2, a selective gelatinase inhibitor, was synthesized and structurally characterized. Two crystals were analyzed, one each for the R and S enantiomers, and the results were compared with the previously reported structure of the racemate. The enantiomerically pure compounds both crystallize with Z′ = 2 in the space group P21, while the racemic mixture crystallizes with Z′ = 1 in the space group P21/c, with disorder in the position of the thiirane group. This disorder accommodates both molecules for each of the enantiomerically pure crystals, showing good overlap of the molecules of the pure enantiomorphs with the components of the centrosymmetric structure.  相似文献   

19.
Crystal structures described as concomitant triclinic ( I ) and monoclinic ( II ) polymorphs of meso-(E,E)-1,1′-[1,2-bis(4-chlorophenyl)ethane-1,2-diyl]bis(phenyldiazene) [Mohamed et al. (2016). Acta Cryst. C 72 , 57–62] have been re-investigated. The published model for II was distorted due to forcing the symmetry of space group C2/c on an incomplete structure model. It is shown here to be a likely three-component superposition of S,S and R,R enantiomers with a lesser amount of the meso form. A detailed analysis of how the improbable distortion in the published model aroused suspicion and the subsequent construction of undistorted chemically and crystallographically plausible alternatives having the symmetry of Cc and C2/c is presented. For the sake of completeness, an improved model for the triclinic P structure of the meso isomer I , revised to include a minor disorder component, is also given.  相似文献   

20.
Tris[o-mercaptophenolato]vanadium(IV) dimer complexes (A)2[V(mp)3NaLL']2 (A = Ph4P+, H2mp = o-mercaptophenol, L = MeCN, L'=EtOH, (1); L' = MeOH, (2)) were prepared by the reaction of anhydrous VC13, and Na2mp in the molar ratio 1:3. Complex (3) (A = Et4N+, L=L' = MeOH) was prepared by the reaction of VC13, Na2mp and Li2S in the molar ratio 1:2:1. The complexes were characterized by X-ray diffraction crystallography, infrared spectra, magnetic susceptibility, and cyclic voltammetric measurements. Complex 2 crystallizes in the triclinic space group P1 with a=12.813(6), b = 14.199(4), c = 12.790(5) Å, α = 112.72(2), β = 104.24(4). γ = 88.68(4)°, V = 2073.6 Å3, and Z=1. The structure was refined to R=0.058. Complex 3 crystallizes in the mono-clinic space group P21/n with a=12.359(3), b=17.452(6), c=14.829(13) Å, βequals;96.51(5)°, V=3177.8 Å3, and Z=2. The final R factor is 0.067. Both of the anions of 2 and 3 contain two [V(mp)3]2? fragments linked by sodium ions through the μ3-O bridges with a crystallographic center of symmetry. The V(IV) atom is in a coordination environment intermediate between a trigonal prism and an ideal octahedron.  相似文献   

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