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1.
Efstathios Gavrielatos Giorgos Athanasellis Olga Igglessi‐Markopoulou 《Journal of heterocyclic chemistry》2002,39(1):185-188
The synthesis of a series of optically active N‐acetyl butenoates 3–5 is described using a facile methodology. These butenoates undergo cyclization to the corresponding N‐acetyl‐2‐alkyl‐pyrrolin‐4‐ones 6,7 retaining their stereochemical integrity. The structure of the newly synthesized compounds has been elucidated through 1H‐13C NMR, IR spectroscopy and their enantiomeric excesses have been measured by chiral HPLC analysis. 相似文献
2.
Anna Gola Evangelia Samartzi Vassilios Bardakos Margarita Petroliagi Olga Igglessi‐Markopoulou John Markopoulos James V. Barkley 《Journal of heterocyclic chemistry》2000,37(4):681-686
An efficient method for the preparation of novel cyano derivatives of 4‐amino‐3‐hydroxybutenoic acids 4–8 and N‐substituted‐2‐aminopyrrolin‐4‐ones 9–18 is described; the structure of compound 13 has been elucidated with X‐ray analysis. 相似文献
3.
The reaction of O‐menthyl phenylphosphonite 1 with aromatic aldehydes in the presence of Me3SiCl provided the O‐menthyl α‐hydroxyphosphinates 2 . Acidic hydrolysis of 2 gave the corresponding α‐hydroxyphosphinic acids 3 . The (+)‐enantiomer of 3a and 3b , adduct of benzaldehyde and 4‐methylbenzaldehyde respectively, were obtained via multiple recrystallization. The absolute configuration of (+)‐ 3a was determined as S by X‐ray crystallography. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:312–315, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10150 相似文献
4.
Lamine Hamdellou Olivier Hernandez Jean Meinnel 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(9):o557-o560
The structures of 4‐dimethylamino‐β‐nitrostyrene (DANS), C10H12N2O2, and 4‐dimethylamino‐β‐ethyl‐β‐nitrostyrene (DAENS), C12H16N2O2, have been solved at T = 100 K. The structure solution for DANS was complicated by the presence of a static disorder, characterized by a misorientation of 17% of the molecules. The molecule of DANS is almost planar, indicating significant conjugation, with a push–pull effect through the styrene skeleton extending up to the terminal substituents and enhancing the dipole moment. As a consequence of this conjugation, the hexagonal ring displays a quinoidal character; the lengths of the C—N [1.3595 (15) Å] and C—C [1.448 (2) Å] bonds adjacent to the benzene ring are shorter than single bonds. The molecules are stacked in dimers with antiparallel dipoles. In contrast, the molecule of DAENS is not planar. The ethyl substituent pushes the nitropropene group out of the benzene plane, with a torsion angle of −21.9 (3). Nevertheless, the molecule remains conjugated, with a shortening of the same bonds as in DANS. 相似文献
5.
Synthesis of new optically active α,α′,β‐trisubstituted‐β‐lactones as monomers for stereoregular biopolyesters 下载免费PDF全文
Rima Belibel Christel Barbaud 《Journal of polymer science. Part A, Polymer chemistry》2015,53(22):2586-2597
Various optically active (4R)‐alkyloxycarbonyl‐3,3‐dialkyl‐2‐oxetanones as monomers were synthesized from L‐(S)‐malic acid in six steps to prepare a new family of stereopolyesters for biomedical applications. The synthesis began with an esterification followed of a dialkylation in the aim to introduce hydrophobic groups as methyl or reactive group as allyl. Then, a saponification has permitted to obtain the corresponding diacids that reacted with appropriate alcohols to furnish different monoesters. The last and most important step was activation of hydroxyl group of monoesters with the asymmetric carbon configuration inversion according to the Mitsunobu reaction. Thus, this reaction has provided lactones from monoesters with 100% enantiomeric excess which was confirmed by 1H NMR and by the synthesis of corresponding isotactic and semicrystalline homopolyesters. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2586–2597 相似文献
6.
Zheng Hong Zhou Yi Long Tang Kang Ying Li Bing Liu Chu Chi Tang 《Heteroatom Chemistry》2003,14(7):603-606
A series of optically active N‐protected α‐aminoketones were synthesized via the Grignard reaction of the Weinreb amides of the N‐tert‐butoxycarbonyl amino acids. Reduction of the α‐aminoketones by sodium borohydride resulted in the corresponding 1,2‐amino alcohols. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:603–606, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10195 相似文献
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Vinay A. Sunagar Prashant R. Latthe Bharati V. Badami 《Journal of heterocyclic chemistry》2007,44(1):1-6
The Schiff bases 3a‐h obtained from 4‐amino‐1,2,4‐triazol‐3‐ones 1a‐h when subjected to Japp‐Klingemann reaction yielded the corresponding 3‐{2‐[(2‐aryl‐5‐methyl‐3H‐[1,2,4]‐triazol‐3‐one‐4‐yl)]‐iminophenyl}‐pentane‐2,4‐diones 4a‐h . These diones on cyclisation with N2H4 yielded the title compounds 5a‐h . The energetics of the Keto‐enol tautomers of the diones was calculated by semiemperical calculations using AM1 and PM3 methods. All these compounds were screened for their antimicrobial activity against few microbes and most of them exhibited fungal inhibition more than the reference drugs used. 相似文献
9.
Martins Ikaunieks Sergey Belyakov Marina Madre 《Journal of heterocyclic chemistry》2006,43(4):943-948
The synthesis of novel 2‐amino‐9‐alkoxyalkylpurine derivatives with both identical and different sulfur containing substituents at positions 6 and 8 of the purine cycle has been accomplished. The thionation and alkylation of the key intermediate ‐ 2‐[2‐(acetylamino)‐6,8‐dichloro‐9H‐purin‐9‐yl]methoxyethyl acetate or its reactions with thiolates were used. The structures of compounds obtained were confirmed by spectroscopic data and X‐ray diffraction analysis. 相似文献
10.
Banadicte Erb Benoît Rigo Bernard Pirotte Daniel Couturier 《Journal of heterocyclic chemistry》2002,39(1):15-28
Starting from 5‐bismethylthiomethylene Meldrum's acid, the synthesis of 5‐diaminomethylene Meldrum's acids and 2‐aminoquinolone derivatives, structurally related to potassium channels openers pinacidil and diazoxide, is described. 相似文献
11.
Alexandra Gaspar Fernando Cagide Elias Quezada Joana Reis Eugenio Uriarte Fernanda Borges 《Magnetic resonance in chemistry : MRC》2013,51(4):251-254
Chromones are heterocyclic compounds of natural or synthetic origin that possess relevant pharmacological activities. Versatile functionalization of the chromone nucleus allows attaining of a chemical diversity suitable to perform structure–activity relationships in drug discovery and development programs. Accordingly, the synthesis and identification of novel chromone carboxamide derivatives with electron‐donating and electron‐withdrawing substituents in different positions of the exocyclic ring are reported in this work. Their complete structural characterization was performed using one‐dimensional and two‐dimensional resonance techniques. The data acquired are useful for a prompt analysis of related compounds that encompass our integrated medicinal chemistry sketch. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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A series of 2,2‐disubstituted 5,6‐diphenyl‐4H‐1,3‐oxathiin‐4‐ones was synthesized by cycloaddition of thiones with benzoylphenylketene, which was generated by the thermal Wolff rearrangement of 2‐diazo‐1,3‐diphenyl‐1,3‐propanedione. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:630–632, 2001 相似文献
14.
Qian Zhao Han‐Geng Chen Chao Qian Xin‐Zhi Chen 《Journal of heterocyclic chemistry》2013,50(1):145-148
2‐Chloro‐3‐amino‐4‐methylpyridine ( 1 ), a key intermediate in the synthesis of nervirapine, was prepared from 2‐cyanoacetamide and 4,4‐dimethoxyl‐2‐butanone via condensation, cyclization, one‐pot reaction of chlorination and hydrolysis, and Hofmann reaction. Utilization of the quadratic orthogonal test resulted in a high yield (62.1%) of the whole process. 相似文献
15.
Lucija Juki Simon Re
nik Jurij Svete Branko Stanovnik Simona Goli Grdadolnik 《Journal of heterocyclic chemistry》2001,38(4):859-868
Alkyl (Z)‐2‐[(E)‐2‐ethoxycarbonyl‐2‐(2‐pyridinyl)ethenyl]amino‐3‐dimethylaminopropenoates 7 and 8 were prepared from ethyl 2‐pyridinylacetate (1) in two steps. Substitution of the dimethylamino group with alkyl‐, aryl‐, or heteroarylamines afforded the corresponding β‐alkyl‐ 22–24 , β‐aryl‐ 25–35 , and β‐herteroaryl‐amino‐α,β‐didehydro‐α‐amino acid 36 and 37 derivatives, intermediates for further preparation of various heterocyclic systems. The orientation around both double bonds were determined by various nmr techniques. 相似文献
16.
This paper describes the synthesis of 4‐amino‐5,6,7,8‐tetrahydrothieno[2,3‐b]quinolin‐5‐ol derivatives ( 3a‐h ) and 4‐amino‐5,6,7,8‐tetrahydrothieno[2,3‐b]quinoline ( 8a ) in good yield by three‐step procedures starting from 2‐aminothiophene‐3‐carbonitrile and 5‐substituted cyclohexane‐1,3‐dione. 相似文献
17.
Mohammed Hmamouchi Robert E. Prud'Homme 《Journal of polymer science. Part A, Polymer chemistry》1991,29(9):1281-1291
The synthesis and optical resolution of α-phenyl β-amino-ethylpropionate led to the preparation of optically active α-phenyl β-propiolactones (PhPL) of different optical purities. The enantiomeric excess of PhPL was determined using 200 MHz 1H-NMR spectroscopy, after complexation with tris[3-(trifluoromethyl hydroxymethylene)-d-camphorato]europium III. It was then polymerized, in bulk and in solution, using a potassium acetate/crown ether complex as initiator. The optically active poly(PhPL)s thus obtained are insoluble in most organic solvents, whereas atactic poly(PhPL)s are soluble in CCl4, CHCl3, and dichloroethane. Several differences are observed between the physical properties of optically active and atactic poly(PhPL)s. However, atactic poly(PhPL)s are semi-crystalline polymers, similar to poly(α-disubstituted β-propiolactone)s, but in contrast with poly(α-methyl β-propiolactone). Melting (Tf) and glass transition temperatures, as well as enthalpy of fusion (ΔH), vary with the optical purity of the polymers. For example, atactic poly(PhPL) exhibits a Tf = 94°C and ΔH = 9 J/g as compared to Tf = 119°C and ΔH = 37 J/g for a poly(PhPL) having an enatiomeric excess of 50%. 相似文献
18.
Liangnian He Yanping Luo Mingwu Ding Aihong Lu Xiaopeng Liu Tianjie Wu Fei Cai 《Heteroatom Chemistry》2001,12(6):497-500
Aromatic‐substituted derivatives of 1,3,2‐diazaphospholidin‐4‐ones 2a–g were readily prepared from 1,3‐diaryl glycinamides 1 by the reaction with hexaethylphosphoric triamide. Their chemical transformation was selectively effected with different thionation reagents to afford thionated products at the phosphorus atom to give 3a–g and at the carbonyl group to give 4a . An oxidation reaction at phosphorus to produce 5a was effected with 10% hydrogen peroxide. Preliminary bioassays revealed that some of the title compounds, 2a–g and 3a–g possess selective herbicidal activity against rape. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:497–500, 2001 相似文献
19.
Richard Voyer Robert E. Prud'Homme 《Journal of polymer science. Part A, Polymer chemistry》1986,24(11):2773-2787
Optically active β-(1,1-dichloroethyl)-β-propiolactone (CH3CCl2-PL), β-(1,1-dichloropropyl)-β-propiolactone (C2H5CCl2-PL), and β-(1,1-dichlorobutyl)-β-propiolactone (C3H7CCl2-PL) were synthesized with enantiomeric excesses of 100, 100, and 84%, respectively. Polymerization was conducted in bulk and toluene solution, under vacuum, using mainly ZnEt2/H2O as initiator. Osmometry analyses indicate molecular weights in the range 10,000–25,000. The polymers thus prepared are semi-crystalline and show large optical rotation values.13 C-NMR was used to show that they have a high degree of isotacticity, indicating that little or no racemization occurs in the course of polymerization. Glass transition, melting and decomposition temperatures are given as a function of the size of the substituent, and their variations are discussed. 相似文献
20.
Petar T. Todorov Nikola D. Pavlov Boris L. Shivachev Rosica N. Petrova Jean Martinez Emilia D. Naydenova Monique Calmes 《Heteroatom Chemistry》2012,23(2):123-130
Novel racemic and optically active constrained N‐phosphonoalkyl bicyclic β‐amino acids have been synthesized via the Kabachnik–Fields reaction of the (RS) or (R)‐1‐aminobicyclo[2.2.2]octane‐2‐carboxylic acids with paraformaldehyde and benzaldehyde, and the dimethyl‐H‐phosphonate. The structure of obtained compounds was characterized by NMR (1H, 13C, and 31P), LC/MS, and X‐ray diffraction analyses. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:123–130, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20759 相似文献