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1.
Biotransformation of (+)-(1R,2S)-fenchol by the larvae of Spodoptera litura was carried out. Substrate was converted to three new terpenoids, (+)-(1R,2S)-10-hydroxyfenchol, (+)-(1R,2R,3S)-8-hydroxyfenchol and (−)-(1S,2S,6S)-6-exo-hydroxyfenchol, and one known terpenoid, (−)-(1R,2R,3R)-9-hydroxyfenchol. These structures were established by NMR, IR, specific rotation and mass spectral studies. 相似文献
2.
Gregory L. FondongEdmond Y. Njua Alexander SteinerCharles F. Campana Lothar Stahl 《Polyhedron》2011,30(17):2856-2862
Syntheses and solid-state structures of zinc and tin(II) compounds, containing the N-silyl-amide ligands (OtBu)(NR)SiMe2, R = tBu (LtBu), or R = p-tolyl (LpTol), are reported. The N-silyl amines were synthesized by modified published procedures from commercially available Me2SiCl2, tBuOH, and tBuNH2, or p-Me-C6H4NH2, respectively. Treatment of SnCl2 with LiLpTol furnished Sn(LpTol)2, which was X-ray structurally characterized and shown to contain two covalent Sn-N bonds and two asymmetrical O → Sn donor bonds. The single-crystal X-ray structure of Sn(LtBu)2 revealed a much more symmetrically-coordinated, pseudo-trigonal-bipyramidal tin atom. Aminolysis of diethylzinc with HLpTol produced [EtZn(LpTol)]2, which crystallized as a centrosymmetric dimer, containing four-coordinate zinc atoms connected by bridging amides. Zinc dichloride, by contrast, reacted with two equivalents of LiLtBu to produce the homoleptic, pseudo-spirocyclic Zn(LtBu)2. 相似文献
3.
16R-Bromopregnane-3S,20S-diol reacted with potassium t-butoxide to afford androst-16-en-3S-ol in a moderate yield via fragmentation reaction. The latter is a key intermediate for the synthesis of 5α-androst-16-en-3-one, as boar sex pheromone, and other steroidal drugs. In addition, 16R,20S-epoxypregnane-3S-ol was also obtained as a major product by changing the reaction solvent. 相似文献
4.
Jun Mifune 《Polymer Degradation and Stability》2010,95(8):1305-1312
Cupriavidus necator H16CAc, previously constructed for production of poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) [P(3HB-co-3HHx)] from soybean oil, was further engineered aiming to increase 3HHx composition in the copolyester. PHA synthase gene derived from Aeromonas caviae on the H16CAc chromosome was replaced by a gene encoding the N149S/D171G mutant and this recombination enhanced PHA productivity as well as slightly increased 3HHx composition. Manipulation of phaACn locus partially reduced the amount of 3HB unit concomitantly with relative increase of 3HHx composition, whereas deletion of phaB1Cn resulted in drastic decline of 3HB unit in P(3HB-co-3HHx). Insertion of phaJAc encoding (R)-specific enoyl-CoA hydratase from A. caviae into pha operon significantly enlarged 3HHx fraction without negative effects on the cell growth and polyester accumulation. Consequently, efficient production of P(3HB-co-3HHx) with 3HHx composition of 5.7-9.9 mol% was successfully achieved from soybean oil by the engineered strains. 相似文献
5.
Vyacheslav E. Platonov Alois Haas Meinolf SchelvisMax Lieb Kira V. DvornikovaOlga I. Osina Tatyana V. RybalovaYuri V. Gatilov 《Journal of fluorine chemistry》2002,114(1):55-61
N-Methyl-, N-n-butyl-, N-t-butylperfluoroarylamines undergo nitrosation with nitrous acid to give the corresponding N-nitroso derivatives. Perfluoroaryl groups were selected from the benzene, indane, biphenyl, naphthalene and pyridine series. According to 1H and 19F NMR spectra, N-nitroso-N-methyl derivatives of polyfluoroarenes consist of E and Z isomers with the former prevailing. The more bulky n-butyl group promotes an increase in the formation of Z isomers. Only Z isomers have been obtained from N-t-butyl derivatives of perfluorinated 4-toluidine and 4-aminopyridine. The structure of the Z isomer of N-nitroso-N-methylperfluoro-4-toluidine is confirmed by X-ray data. 相似文献
6.
Tsukasa Furuya 《Journal of fluorine chemistry》2009,130(3):348-806
We prepared a novel fluorous deoxy-fluorination reagent N,N-diethyl-α,α-difluoro-[3,5-bis(1H,1H,2H,2H-perfluorodecyl)benzyl]amine (1b) from 3,5-diiodobenzoic acid (3b) via N,N-diethyl-3,5-bis(1H,1H,2H,2H-perfluorodecyl)benzamide (2b) in four steps and used it for the fluorination of alcohols and diols. After the fluorination reactions, the isolation of the products and recovery of 2b was performed by extraction with a fluorous/organic solvent system. 相似文献
7.
Miwako Mori Tomohiro Tomita Yoichi Kita Tsuyoshi Kitamura 《Tetrahedron letters》2004,45(22):4397-4399
Synthesis of N-tosylanatoxin-a was achieved by metathesis of enyne in cis-substituents on a pyrrolidine derivative. Metathesis reactions of enyne having terminal alkyne using various ruthenium-carbene complexes did not give a good results. However, when the terminal alkyne was protected with a TMS group, the reaction proceeded smoothly using a second-generation ruthenium-carbene complex to give the desired cyclized compound in high yield. Oxymercuration followed by Dess-Martin oxidation afforded N-tosylanatoxin-a. 相似文献
8.
Humberto E. Ortega Young Yongchun Shen Karen TenDyke Nivia Ríos Luis Cubilla-Ríos 《Tetrahedron letters》2014
A new polyhydroxylated macrolide, named mangiferaelactone (1) was isolated from a solid culture of the endophytic fungus Pestalotiopsis manguiferae, together with ten known compounds [(6S,1′S)-LL-P880α; (6S,1′S,2′R)-LL-P880β; (1′S,2′R)-LL-880γ; (1′R)-dehydropestalotin; (−)-5-carboxylmellein; (−)-5-methylmellein; (−)-5-hydroxylmethylmellein; arabenoic acid; 5,6-dihydro-4-methoxy-2H-pyran-2-one; and the (−)-2-hexylidene-3-methylsuccinic acid]. P. manguiferae was isolated from Hyptis dilatata, a small shrub common in the central region of Panama. The structure of compound 1 was elucidated by a combination of spectroscopic methods (IR, MS, optical rotation, 1D and 2D NMR spectroscopy). The absolute configuration of 1 was established as 4R,7R,8R,9S by application of vibrational circular dichroism (VCD). Compound 1 showed a minimum inhibitory concentration (MIC) of 1.6863 mg/mL against Listeria monocytogenes, and 0.5529 mg/mL against Bacillus cereus. No activity was observed for compound 1 against Plasmodium falciparum or Trypanosoma cruzi; likewise, no cytotoxic activity was observed against A2058 and H522-T1 cells. 相似文献
9.
Blaise Mavinga MbalaJan Jacobs Pieter ClaesVirima Mudogo Norbert De Kimpe 《Tetrahedron》2011,67(45):8747-8756
As part of our research on 2-aza analogues of pentalongin, the active principle of Pentas longiflora Oliv., the first synthesis of 2,3-disubstituted benzo[g]isoquinoline-1,5,10(2H)-triones via 3,4-disubstituted 6-hydroxybenzo[g]furo[4,3,2-de]isoquinoline-2,5(4H)-diones as the key intermediates is reported. The latter compounds have been prepared by treating 2-methoxycarbonyl-1,4-naphthoquinone with N-substituted enaminoesters under acidic conditions. These reagents are easily accessible from readily available 1,4-dihydroxy-2-naphthoic acid, β-ketoesters and primary amines. Finally, a short synthesis of substituted benzo[g]isoquinoline-1,5,10(2H)-triones is achieved by an oxidative addition of N-substituted enaminoesters onto methyl 1,4-dihydroxynaphthalene-2-carboxylate. 相似文献
10.
Miron Teodor Căproiu Florea Dumitrascu Sergiu Shova Ileana Cornelia Chirită Alexandru Vasile Missir Dana-Mihaela Cioroianu 《Tetrahedron letters》2014
New S-thiocarbamates possessing a 10,11-dihydro-5H-dibenzo[a,d]cycloheptene moiety were obtained unexpectedly in the process of preparing new O-thiocarbamates starting from 5-dibenzosuberol (10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ol) and aroyl-isothiocyanates. These compounds were obtained via a benzylic Newman–Kwart rearrangement mechanism. The structures of the new thiocarbamates were confirmed by elemental analysis, IR, and NMR spectroscopy and by X-ray crystallography. 相似文献
11.
Ashot Khrimian 《Tetrahedron》2005,61(15):3651-3657
All eight geometric isomers of methyl 2,4,6-decatrienoate were synthesized from readily accessible starting materials by fully exploiting Wittig-type olefinations, and taking advantage of an easy separation of 2E and 2Z unsaturated esters. The aggregation pheromone of the brown-winged green bug, Plautia stali, methyl (E,E,Z)-2,4,6-decatrienoate (also a cross-attractant for the brown marmorated stink bug, Halyomorpha halys), was expediently produced in two easy steps from (E)-4,4-dimethoxy-2-butenal in 55% yield. The sex pheromone of the red-shouldered stink bug, Thyanta pallidovirens, methyl (E,Z,Z)-2,4,6-decatrienoate, was conveniently synthesized from 2,4-octadiyn-1-ol in 32% yield using in situ manganese dioxide oxidation-Wittig condensation in a key step. 相似文献
12.
Anatoliy Marchenko Georgyi KoidanAnastasiya Hurieva Aleksandr SavateevAleksandr Kostyuk 《Tetrahedron letters》2013
A direct synthetic approach to C-phosphanyl-N,N-dialkyl-N′-aryl(alkyl)-formamidines was developed. It was shown that phosphorylation of the formamidines proceeds at the nitrogen atom affording N-phosphanylformamidinium salts. Upon deprotonation, these salts gave C-phosphanylformamidines via formation of carbenes followed by a 1,2-phosphorus shift. 相似文献
13.
Of the three closo-carborane isomers (C2B10H12), closo-1,2-carborane has been used most widely in the synthesis of carboranyl amines. However, closo-1,2-carboranes are prone to deboronation to nido-7,8-carborane under various conditions including attack by basic amino groups. In order to overcome this problem, closo-1,7-carboranyl ethyl-, propyl-, and butylamine were synthesized, which should be more stable towards basic deboronation than their closo-1,2-carboranyl counterparts. These closo-1,7-carboranyl amines (5, 18 and 19) were synthesized using two different methods, both starting from the corresponding closo-1,7-carboranyl alkyl iodides (3, 14 and 15). One of the carboranyl alkyl amine (5) was conjugated with folic acid to form a closo-1,7-carborane-folic acid bioconjugate (20). 相似文献
14.
Castanolide (1) and epi-castanolide (2), two novel diterpenoids possessing a unique seco-norabietane skeleton, were isolated from Salviacastanea Diels f. pubescens Stib. Their structures and relative stereochemistry were elucidated by extensive NMR analysis and confirmed by single-crystal X-ray diffraction study. A possible biosynthetic pathway of these two compounds was also proposed. 相似文献
15.
Jong Hwa Jeong Young Hun An Youn K. Kang Quang Trung Nguyen Hyosun Lee Bruce M. Novak 《Polyhedron》2008
The reaction between ZnCl2 and (S)-N-ethyl-N-phenyl-2-pyrrolidinemethanamine (S-EPP) as a chiral ligand affords [ZnCl2(S-EPP)], whose structure has been determined by X-ray crystallography. [ZnEt2(S-EPP)] has demonstrated high activity toward the polymerization of rac-lactide with a maximum turnover frequency (TOF) of 121. Despite the intended stereocontrol by employing a chiral ligand, however, the observed heterotacticity was limited to under 0.6. The MWDs of the PLAs were found to be modulated by changing the solvent or controlling the concentration of the monomer in the solution. The glass transition temperature (Tg) was critically dependent on the MW within the narrow MWD regime, but the dependence became significantly shallow when the MWD was broadened. 相似文献
16.
Vladimir CherkasovNikolay Druzhkov Tatiana KocherovaGeorgii Fukin Andrey Shavyrin 《Tetrahedron》2011,67(1):80-84
The interaction of 3,5-di-tert-butyl-o-benzoquinone with secondary amines has been studied. The synthetic procedure was developed in order to synthesize a series of new N,N-disubstituted o-aminophenols. The interaction of 3,5-di-tert-butyl-o-benzoquinone with dimethylamine leads to 2-(N,N-dimethylamino)-4,6-di-tert-butyl-phenol, which is oxidized in the reaction medium by the parent 3,5-di-tert-butyl-o-benzoquinone forming spirocompound 4,5′,6,7′-tetra-tert-butyl-3′-methyl-3′H-spiro[1,3-benzodioxol-2,2′-[1,3]benzoxazole]. 相似文献
17.
A new metabolite, infectopyrone (1), has been isolated from the filamentous fungus Alternaria infectoria. The structure of 1 was elucidated by analysis of 2D NMR spectroscopic data. Compound 1 is an α-pyrone resembling known toxins, and is a useful phenotaxonomic marker for the A. infectoria species-group. Infectopyrone (1) was also produced by species within Stemphyllium and Ulocladium, and found in mouldy food. 相似文献
18.
Thiamphenicol and florfenicol have been synthesized stereoselectively from enantiomerically pure 4-methylsulfanyl-mandelonitrile, which was obtained by hydrocyanation reaction of 4-methylsulfanyl-benzaldehyde catalyzed by (R)-hydroxynitrile lyase of Badamu (Prunus communis L. var. dulcis Borkh, almond from Xinjiang, China). It was found to be a highly effective bio-catalyst for this reaction after an extensive screening. 相似文献
19.
Yuichi Teramoto 《Journal of organometallic chemistry》2011,696(21):3402-3407
A thermodynamically less stable cis isomer of 1,2-diphosphacycle was prepared from the corresponding trans isomer. Diphosphine, in which a PhP-PPh bond bridges the 1,8-positions of naphthalene, 1,2-diphenyl-1,2-dihydronaphtho[1,8-cd][1,2]diphosphole (1), was first prepared according to a previously reported method, and the trans isomer of 1 was irradiated in tetrahydrofuran with UV-vis light to reach equilibrium with cis-1 in a trans:cis ratio of 1:2. When a similar photochemical conversion was carried out using a saturated hexane solution of trans-1, cis-1 was precipitated in a good yield of 94%. The configuration of cis-1 was confirmed by X-ray analysis. Both cis- and trans-1 diphosphine ligands were used for the preparation of binuclear gold complexes. The crystal structure of (μ-cis-1)-[AuCl]2 demonstrated that the two lone pairs of cis-1 are suitably directed for arrangement of the two gold centers in close proximity to each other. The two independent (μ-cis-1)-[AuCl]2 molecules in the crystal were found to form a dimer through the multiple intermolecular interaction among the gold centers. 相似文献
20.
Catalytic activity of Mn(III) and Fe(III) complexes of meso-tetra(n-propyl)porphyrin, MnT(n-Pr)P(X) and FeT(n-Pr)P(X) (X = Cl, SCN, OAc) in oxidation of olefins with tetra-n-butylammonium periodate at room temperature has been studied. The influence of different parameters including the molar ratio of catalyst to imidazole, type of counter ion (X) and oxidative stability of metalloporphyrins on the efficiency of the catalysts was investigated. The results of competitive oxidation of cis- and trans-stilbene suggest the presence of a high-valent Mn-oxo as the predominant oxidant species in equilibrium with a six coordinate complex, MnT(n-Pr)P(ImH)(IO4) in the case of MnT(n-Pr)P(OAc). An unusual preference for trans-stilbene over cis-stilbene was observed in the reaction catalyzed by FeT(n-Pr)P(OAc). Control reaction indicated a significant cis- to trans-isomerization (81%) in oxidation of cis-stilbene catalyzed by FeT(n-Pr)P(OAc) which may explain the observed unusual cis to trans-stilbene oxide ratio. While oxidation of cyclooctene and styrene led to the exclusive formation of the corresponding epoxides, oxidation of cyclohexene gave 2-cyclohexe-1-ol and cyclohexene oxide as the products. However, the results of this study clearly demonstrate the key role played by the group substituted at the meso positions of metalloporphyrins on their catalytic activity, apart from the electron-donating or electron-withdrawing properties of the substituents. 相似文献