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1.
M. Judith Percino Víctor M. Chapela Ling-Fa Montiel Enrique Pérez-Gutiérrez José Luis Maldonado 《Chemical Papers》2010,64(3):360-367
An efficient Knoevenagel route using green chemistry conditions was applied for the synthesis of halogen- and cyano- substituted
pyridinevinylene compounds. Absorption and fluorescence emission spectra of these conjugated compounds were recorded and compared
in order to evaluate the effect of substituents on the electronic properties of pyridinevinylene compounds. The substituents
studied were terminal Cl and F, two or three aromatic rings, as well as a cyano group attached to a C=C double bond. The compounds
synthesized are: (E)-2-(4-fluorostyryl)pyridine, (E)-2-(4-chlorostyryl)pyridine, (E)-4-(4-chlorostyryl)pyridine, 2,3-diphenylacrylonitrile, 3-phenyl-2-(pyridin-2-yl)acrylonitrile, 3-phenyl-2-(pyridin-3-yl)acrylonitrile,
2-phenyl-3-(pyridin-2-yl)acrylonitrile, 3,3′-(1,4-phenylene)bis(2-phenylacrylonitrile), 3,3′-(1,4-phenylene)bis(2-(pyridin-2-yl)acrylonitrile),
and 3,3′-(1,4-phenylene)bis(2-(pyridin-3-yl)acrylonitrile). The solvent-free method used in this work allows obtaining each
compound by controlling the reaction temperature. The compounds were characterized by infrared spectroscopy and 1H-NMR spectroscopy. 相似文献
2.
The raspailynes (novel long-chain enol ethers of glycerol having the enol ethers double bond conjugated in sequence, to an acetylenic and an olefinic bond, isolated from the North-East-Atlantic sponges Raspailia pumila and R. ramosa) are stable under normal hydrolytic conditions for enol ethers. In contrast, when their solutions are evaporated, these lipids such as raspailyne Bl (=(?))-3-[(1Z,5Z)-(tetradeca-1,5-dien-3-ynyl)oxy]-1,2-propanediol;(?- 2 ) rapidly react with aerial O2 under normal laboratory-daylight conditions, with rupture of the C=C enol ether bond to give 1-O-formylglycerol ( 3 ) and an aldehyde (such as tridec-4-en-2ynal( 4 ) from (?)- 2 ). This reaction must be caused by triplet O2, since thermally generated singlet O2 has no effect on (?)- 2 in solution. That the mere presence of an enol-ether moiety conjugated to an acetylenic group is responsible for such a behaviour is demonstrated with the model compounds 1-methoxypentadec-1-en-3-yn-5-ol ( 6a ) and its 5-O-acetyl or 5-O-tetra-hydropyranyl derivatives 6b and 6c , respectively. Resistance to both hydroytic conditions and singlet O2 of these compounds is thought to arise from electron depletion at the enol-ether C(beta;) atom by the acetylenic group. Plausible reaction pathways for enol-ether bond rupture in these compounds by aerial O2 are outlined. 相似文献
3.
Sreenu Pavurala Krishnaiah Vaarla Rajeshkumar Kesharwani Lieve Naesens Sandra Liekens 《合成通讯》2018,48(12):1494-1503
A series of novel 3,3′-(3,3′-(dihydroxy/hydroxyethane-1,2-diyl)bis(7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine-6,3-diyl))bis(2H-chromen-2-ones) were prepared by the condensation of thiocarbohydrazide with tartaric acid or malic acid followed by various 3-(2-bromoacetyl)-2H-chromen-2-ones in two steps with good yields. All the synthesized compounds were characterized by analytical and spectral (IR, 1H NMR, 13C NMR, and mass) data. These synthesized bis(triazolothiadiazinyl coumarin) compounds were evaluated for broad spectrum of antiviral activity. Among all the tested compounds, compound 5f exhibited antiviral activity against H1N1 virus. The molecular docking studies of these compounds against H1N1 neuraminidase enzyme were performed. The binding affinity and binding values were compared with standard drugs. 相似文献
4.
Yun-Nan Yan Dan-Yan Lin Wen-Long Pan Xiu-Ling Li Yi-Qian Wan Yu-Liang Mai Hua-Can Song 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,74(1):233-242
Eight 2-(9-phenanthrenyl)-, 2-(9-anthryl)- and 2-(1-pyrenyl)-1-alkyl-benzimidazole compounds, three 2-(9-anthryl)-1-alkylphenanthroimidazole compounds and five 4,5-diphenyl-1-alkyl-2-(9-anthryl)imidazole compounds were synthesized by alkylation reactions of the corresponding benzimidazole, phenanthroimidazole or imidazole compounds. 2-(10-Bromo-9-anthryl)-1-alkyl-benzimidazole compounds were prepared by bromination reaction of 2-(9-anthryl)-1-alkylbenzimidazole compounds. All the synthesized compounds were characterized by elemental analysis, 1H NMR, 13C NMR, MS or HRMS; their absorption coefficients (), maximum absorption λamax, fluorescence emission maximum λem, Stokes shifts and fluorescence quantum yields (ΦF) in ethyl acetate were determined; their fluorescent lifetimes (T1 and T2) were measured in ethyl acetate and in solid state, respectively. The crystal structure of 2-(9-anthryl)-1-n-butyl-4,5-diphenylimidazole (12a) was determined to be triclinic, space group P-1 types, using single crystal X-ray crystallography technique. The results showed that these compounds exhibited moderate fluorescence-emission abilities and higher solubility in most organic solvents than their corresponding starting materials. The relationships between the optical behaviors and structures for these compounds were discussed. 相似文献
5.
Jnos Szab Ernest Bani-Akoto Gyrgy Dombi Gbor Bernth Lajos Fodor PL Sohr 《Journal of heterocyclic chemistry》1992,29(6):1513-1517
The ring-closure reactions of N-(3,4-dimethoxyphenylthiomethyl)-2-nitrobenzamide derivatives 5a,b with phosphoryl chloride gave 4-(2-nitrophenyl)-2H1,3-benzothiazine derivatives 7a,b , which on reduction yielded 4-(2′-aminophenyl)-3,4-dihydro-2H-1,3-benzothiazines 8a,b. Reaction of these compounds with phosgene led to a new heterocyclic ring system, 6H,8H-quinazolino[3,4-c][1,3]benzothiazine derivatives 9a,b. The structures of the title compounds were proved via their ir and nmr (1H, 13C) spectra. 相似文献
6.
Michele D'Ambrosio Antonio Guerriero Francesco Pietra Marina Ripamonti Ccile Debitus Jean Waikedre 《Helvetica chimica acta》1996,79(3):727-735
Agelastatin A ( 1 ), an unusual alkaloid of the axinellid sponge Agelas dendromorpha from the Coral Sea, can be selectively acetylated (→ 7 ) or methylated at OH? C(8a) (→ 4 ), peracetylated (→ 8 ) or permethylated at OH? C(8a), NH(5), and NH(6) (→ 5 ), or, finally, subjected to C(9)? C(8a) (→ 14 ) or C(5b)? C(8a) β-elimination (→ 11–13 ), in a regiospecific manner or not, depending on the reaction conditions. Under acidic conditions, compound 12 adds H2O or MeOH, regioselectively though not endo/exo stereoselectively, giving transoid/cisoid mixtures 1/18 or 4/19 , respectively. Similarly 11 or 13 add MeOH to give mixtures (?)- 2/20 or 15/16 , respectively. Compound 13 also adds AcOH giving mixture 8/17 . The intermediate cisoid form obtained on treatment of 21 with H3O+ undergoes N(5)? N(6) bridging affording pentacyclic 22 which constitutes a proof for the cisoid configuration. From conformational studies, rules are devised that allow assigning the configuration of these compounds from NMR data. In vitro comparative cytotoxicity assays of these compounds show that for high cytotoxic activity, such as of 1 in vivo, unsubstituted OH? C(8a), H? N(5), H? N(6) moieties are needed in the natural B/D transoid configuration. 相似文献
7.
T. Premkumar S. Govindarajan W.-P. Pan R. Xie 《Journal of Thermal Analysis and Calorimetry》2003,74(1):325-333
Some new transition metal imidazolehydrogendicarboxylate hydrates of empirical formula M(Himdc)2·nH2O (H
2
imdc=4,5-imidazoledicarboxylic acid), where n=2 for M=Mn, Ni, Zn, Cd and n=3 for M=Co, have been prepared in aqueous solution. The compounds have been characterized by analytical, electronic and IR spectroscopic,
thermal analysis and X-ray powder diffraction studies. Electronic spectroscopic data suggest that the Co and Ni compounds
are of spin free (high spin) type with octahedral geometry. For these compounds, the IR bands in the region 1750-1710 cm-1 has been assigned to stretching vibrations of the non-ionized carboxylic group, confirming that the ligand is monoionized.
IR spectra also suggest the unidentate co-ordination behaviour of carboxylate (vasy =1570 and vsym=1390 cm-1) groups of the imidazoledicarboxylate monoanion. The thermal behaviour of these compounds has been studied by simultaneous
TG-DTA techniques. All of these compounds are dihydrates except cobalt which is a trihydrate. Thermal decomposition studies
show that they lose two water molecules endothermally in the range 200-270°C to give their anhydrous compounds, indicating
that these water molecules are coordinated to the metal. The anhydrous compounds further decompose exothermally in the range
300-620°C to leave the respective metal oxides via the metal oxalate intermediates. Whereas the manganese compound undergoes
pyrolytic cleavage in a single step to give the manganese carbonate as the final residue. Isomorphic nature of these compounds
is evident from XRD data. Six-coordination for the metal atoms has been proposed based on the thermal analysis, visible and
IR spectroscopic results.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
Joseph Rabinowitz 《Helvetica chimica acta》1969,52(1):255-261
Comparison of the NMR. spectra in CDCl3 of the heterocyclic bases obtained from the cyclisation of ω-(N-thiocarbamoylamino) ethyl (or propyl)-alcohols (or their orthophosphoric or sulfuric monoesters) to those of model compounds II (n = 1 or 2) and III (n = 1 or 2) has shown that: (1) In the case of five membred rings the C?N double bond is always endocyclic (Ib, n = 1) should R be aromatic, araliphatic or aliphatic; (2) In the case of six membered rings the C?S double bond is cnclocyclic when R is aliphatic or araliphatic (Ib, n = 2), and exocyclic when R is aromatic (I a, n = 2), with the exception of 2-(o-carboxyphcnylamino)-dihydro-δ2-m (Ib, n = 2, K = o-carboxyphcnyle). In CF, COOH, all five membered rings (I b, n = 1) show a triplet for the C-4 methylenic protons, whereas all the six membered rings (Ia or I b, n = 2) with the exception of I b, n = 2, R = o-carboxyphenyle, are represented b y a double triplet for the C-4 protons (samt. protonated spccics). Only one triplet is observed when the 3 position is substituted. Thiocarbamoylation of hydrazinoethanol or its orthophosphoric or sulfuric monoesters canoccur at either of the two nitrogen atoms, thus yielding upon cyclization five- (IT′) or six-membered rings (Va or Vb). The NMR spectra of compounds I V in (CIl,), SO show a singlet for 2 amino pro-tons (3-amino) and there is no further structural problem. The NMR spectra of compounds T′ in (CT), SO show a triplet for one amino proton coupling with the neighboring methylenic protons. I n this case, mode1 compounds are needed to assign the position of the C?N double bond ( e x cyclic V a or cndocyclic V b). When R = o-carboxyphenylc, the C?N double bond is probably endoc, yclic (Vb) because this ccimpound and 2-(o-carboxyphenvlarnino)-dihydro-δ2 have very similar UV spectra. 相似文献
9.
Reaction of 3-bromo-3-methylbutan-2-one ( 1 ) with mercapto-esters 2 affords 5-oxo-3-thiahexanoates 3 which cyclize to thiane-3,5-diones 4 . Conversion of these dicarbonyl compounds to their ethyl enol ethers 5–7 followed by reduction with LiAlH4 gives 2H,6H-thiin-3-ones 8–10 . On irradiation (350 nm) in either MeCN, benzene, or i-PrOH, these newly synthesized heterocycles isomerize efficiently to 2-(alk-l-enyl)thietan-3-ones 11–13 . The rearrangement seems to proceed from an excited singlet state, as it is not quenched by naphthalene, and also occurs with the same efficiency in the presence of added alkene. A (9-S-3) sulfuranyl-alkyl biradical formed by bonding of C(α) of the enone C?C bond on sulfur is discussed as possible intermediate. 相似文献
10.
Rita Vaickelionienė Vytautas Mickevičius Gema Mikulskienė Maryna Stasevych Olena Komarovska-Porokhnyavets Volodymyr Novikov 《Research on Chemical Intermediates》2011,37(8):1009-1027
N′-(4-Oxo-1,4-dihydronaphthalen-1-ylidene)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides and N′-(3-methyl-4-oxo-1,4-dihydronaphthalen-1-ylidene)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides were synthesized by reactions
of 5-oxo-1-phenylpyrrolidine-3-carbohydrazides with 1,4-naphthoquinone or 2-methyl-1,4-naphthoquinone. The alkylated analogues
of the above products were obtained using ethyl iodide. The interaction of 5-oxo-1-phenylpyrrolidine-3-carbohydrazides with
2,3-dichloro-1,4-naphthoquinone was followed by formation of N′-(3-chloro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides. All these compounds were characterized
using 1H, 13C NMR, IR and mass spectra. Some of the new compounds were tested for the antimicrobial and antifungal activity. 相似文献
11.
Alfredo Carlos Alder Peter Rüedi Roland Prewo Jost H. Bieri Conrad Hans Eugster 《Helvetica chimica acta》1986,69(6):1395-1417
Novel Diterpenoids from Leaf-Glands of a Plectranthus sp. from Rwanda More than 20 highly modified abietanoid compounds belonging to 6,7-dioxocoleons, serveral kinds of royleanones, spirocoleons, extended quinones, quinone methides, and 1,4-phenanthraquinones have been isolated from a Plectranthus sp. from the borders of Lake Kiwu (Rwanda). The structure of plectranthon A ( 1 ), a 5,7,8-trimethyl-1,4-phenanthraquinone, has been confirmed by an X-ray analysis of its p-bromobenzoate. It is twisted around the C(4)–C(5) moiety; this fact renders the molecule chiral. Notable features of the hydroxylation pattern in all of the isolated compounds are: (a) a predominant hydroxylation at C(16) (abietan numbering) leading to the (15S)-configuration of the 2-hydroxy-l-methylethyl side-chain and to the (13S, 15R)-configuration of the derived spirocyclopropanes and to the derived (S)-2-hydroxypropyl side-chain; (b) the 6β,7α-dihydroxylation which, together with further hydroxylations at C(3) and/or C(2), are considered as a prerequisite for the formation of the conjugated system extending over rings A, B and C (e.g. in the coleons E and F), hence allowing a complete aromatization of the basic ring skeleton. The reasons for these extensive dehydrogenation and oxygenation reactions that cost the plant a great many of oxidation equivalents are not clear. Presumably, these modifying reactions preceed the degradation of the ring system. 相似文献
12.
The treatment of the 1, 2:5, 6-di-O-isopropylidene-α-D -ribo- and xylo-hexofuranos-3-uloses with cyanomethylenetriphenylphosphorane led in each case, and in almost quantitative yields, to a pair of geometrical isomers of C-cyanomethylenic sugars having respectively the ribo and the xylo configurations. Permanganate oxidation of these branched-chain unsaturated sugars afforded the corresponding gem-hydroxyformyl compounds bearing the formyl group on the more hindered face of the molecule. The formyl group of these sugars is easily derivatized to an oximino or reduced to a hydroxymethyl. The configuration at the new asymmetric carbon has been established by comparison with known compounds or by synthesis of a C(3) epimer by the classical route involving a Grignard reagent. 相似文献
13.
Ursula Schmid Heinz Heimgartner Hans Schmid Willi E. Oberhnsli 《Helvetica chimica acta》1976,59(8):2768-2785
Addition Reactions of 3-Dimethylamino-2, 2-dimethyl- 2 H-azirine and Isothiocyanates. The title azirine readily reacts with two molecules of benzyl- or methylisothiocyanate to form the zwitterionic 1:2 addition compounds 4 and 13 , respectively (Scheme 2). The presumed 1:1 addition products, which are intermediates in the formation of 4 and 13 , cannot be detected. The structure of 4 and 13 follows from their spectroscopic and chemical properties. With water they give the thiourea derivates 5 and 14 , respectively; treatment with aqueous acid leads to the Δ2-1, 3-thiazolin-5-on-derivates 7 and 15 , respectively. With sodium borohydride compounds 8 and 16 , respectively, are obtained (Scheme 2). The zwitterionic compounds 4 and 13 are able to react further with one molecule of the isothiocyanates to give, in high-yield, triazines 9 and 18 , respectively (Scheme 3). The structure of these compounds was again derived from their spectroscopic data. The mechanism for the formation of 9 and 18 is given in Scheme 3. Acid catalysed hydrolysis of 9 and 18 lead to the trithiocyanuric acid derivates 12 and 20 , and to the spiro compounds 11 and 19 , respectively (Sceme 6). Reaction of 4 with one molecule of phenylisocyanate gives triazine 10 (Scheme 5). According to the X-ray analysis of the methyl compound 18 , there are strong steric interactions in this molecule which are due to the side chain. This is demonstrated by the small distances between C(2) … C(13), N(7) … C(11), and C(8) … C(11) (Table 4). These steric interactions, in addition, cause widening of the bond angles N(1)? C(2)? N(7) and C(9)? N(10)? C(11) (Fig.2). Furthermore, the triazine ring is no longer planar. This deformation of the ring diminishes repulsion between the methyl groups C(13) and C(15). 相似文献
14.
Graziano Guella Ines Mancini Helmut Zibrowius Francesco Pietra 《Helvetica chimica acta》1988,71(4):773-782
From the scleractinian coral Tubastraea sp. (Dendrophylliidae) collected at Palawan, Philippines, 3′-deimino-3′-oxoaplysinopsin ( 4 ) and 6-bromo-3′-deimino-3′-oxoaplysinopsin ( 6 ) are now isolated as 5:2 mixtures of (E/Z) stereoisomers. The 3′-deimino-2′,4′-bis(demethyl)-3′-oxoaplysinopsin ( 7 ) and 6-bromo-3′-demino-2′,4-bis(demethyl)-3′-oxoaplysinopsin ( 5 ) are isolated as 2:3 and 1:1 (E/Z) mixtures, respectively, from another dendrophylliid, Leptopsammia pruvoti, collected near Marseille, Mediterranean coast of France. Larger amounts of these and related compounds, needed for a full structural determination, are obtained by synthesis. Thus, condensations of indol-3-carboxaldehyde (9) or of its 6-bromo derivative 14 with hydantoin (15) , 3-methylhydantoin (11) , or 1,3dimethylhydantoin (10) give the prevalent natural aplysinopsins with high stereospecificity. The minor stereoisomers (Z)- 4 , (Z)- 6 , (E)- 7 , and (E)- 5 are obtained by (E/Z) photoisomerization under UV light of the condensation mixtures. The configuration is assigned from larger H? C(8)/C(5′) 1H, 13C couplings in the (E) than in the (Z) isomer, and, in the case of 4 and 6 , from NOE enhancement at Me? N(2′) on irradiation at H? C(8). The stereospecificity of the condensations is attributed to steric inhibition to planarity in the rate-limiting transition states, due to N(2′)/H? C(2) repulsion with (Z)- 4 and (Z)- 6 , or to C(5′)?O/H? C(2) repulsion with (E)–7 or (E)- 5 . As the aplysinopsins undergo (E/Z ) phostoisomerization also under the daylight conditions of the laboratory, their isomeric composition in nature can not be presently assessed. 相似文献
15.
1,2-Dihydro-2-(4,5-dihydroimidazol-2yl)phthalazin-1-ol 1 reacts exothermically with dialkyl acetylenedicarboxylates to give 3-[2-(4,5-dihydro-1H-imidazol-3-iurn-2-yl)-1,2-dihydro-1-phthalazin]-1,4-dialkoxy-1,4-dioxo-2-buten-2-olates 7 and 8 . Enolic ester compounds underwent further transesterification reactions with formation of the betaines 9 and 10 . The unequivocal structural assignement of these compounds was achieved by spectroscopic 1H and 13C nmr methods as well as X-ray analysis of 7 . 相似文献
16.
Venkatesh K. Pandey Kalpana Chaturvedi Ruchi Chandra Om P. Pandey Soumitra K. Sengupta 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1401-1408
Abstract A series of biologically active organophosphorus compounds have been synthesized by the reactions of O,O-diethylchlorophosphate with Schiff bases derived from 5-(phenyl/substituted phenyl)-2-hydrazino-1,3,4-oxadiazole and salicylaldehyde/2-hydroxyacetophenone. The compounds have been characterized on the basis of analyses and spectral (IR, 1H, 13C NMR) data. Fungicidal activities of these derivatives against Colletotrichum falcatum, Fusarium oxysporum, and Curvularia pallescence have been evaluated. All compounds showed moderate to significant antifungal activity. 相似文献
17.
Abstract Three types of nematogenic compound, 4-[2-(trans-4-alkylcyclohexyl)ethyl]-4′-alkyltolanes, 2-fluoro-4-[2-(trans-4-alkylcyclohexyl)ethyl]-4′-alkyltolanes and 4-[2-(trans-4-alkylcyclohexyl)ethyl]-4′-halogenotolanes, have been synthesized and their transition temperatures and enthalpies determined. Their bulk viscosity and birefringence have been estimated from those of mixtures with other liquid-crystalline compounds. These compounds have been found to be excellent materials for twisted nematic displays, because of their wide nematic temperature range, high birefringence (Δn = 0·26), and low viscosity (η = 21 cP at 20°C). Several related compounds having other central linkages, namely -CH2O-, a single bond or -COO-, in place of the 1,2-ethylene group, have also been studied. 相似文献
18.
Asma Balakrishna Kalluraya Nagaraja Manju Chigahally Lakshmegowda Sharath 《Journal of heterocyclic chemistry》2020,57(8):3105-3115
A novel series of 5-(p-(prop-2-ynyloxy)phenyl)-3-aryl-4,5-dihydropyrazole-1-carbothioamides 2a-f and functionalized 2-(3-(aryl)-5-(4-(prop-2-ynyloxy)phenyl)-4,5-dihydropyrazol-1-yl)-4-(3-arylsydnone-4-yl)thiazoles 4a-l were synthesized. The newly synthesized compounds were elucidated by analytical and spectral analysis. From the single-crystal X-ray diffraction method, it was observed that 2d crystallizes in a monoclinic crystal system with P21/n space group. The compounds 2d crystallized with cell parameters a = 15.0614 (19) Å, b = 6.0805 (7) Å, c = 20.903 (7) Å, α = 114.136 (6)o, β = 110.709 (14) o, γ = 96.553 (5) o, V = 1790.6 (4) Å3, Z = 4. From the Hirshfeld surface computational method, the major intercontacts present in these molecules are H…H (31.6%), C…H (18.2%) and S…H (12.2%), respectively. The newly synthesized compounds were tested for their ability to bleach 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical using DPPH scavenging assay. Among the synthesized compounds carbothioamide compounds 2c (90.7%) and 2b (89.8%) exhibited good DPPH scavenging activity compared to the rest of the compounds. Most of the synthesized carbothioamide molecules ( 2a-f ) found to be potent compared to the thiazole derivatives ( 4a-l ). 相似文献
19.
Monika Kořenková Dr. Ing. Martin Hejda Prof. Milan Erben Dr. Ing. Robert Jirásko Prof. Dr. Roman Jambor Prof. Aleš Růžička Dr. Elena Rychagova Prof. Sergey Ketkov Prof. Libor Dostál 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(56):12884-12888
The reaction of N,C,N-chelated stibinidene ArSb ( 1 ) (Ar=C6H3-2,6-(CH=NtBu)2) with selected N-alkyl/aryl-maleimides RN(C(O)CH)2 (R=Me, tBu, Ph) gave the addition products with bridged bicyclic [2.2.1] structure containing an antimony atom at the bridgehead position, fused with a 6-membered benzene and a 5-membered N-alkyl/aryl-pyrrolidine ring. These compounds were completely characterized. More importantly, additional studies showed that these reactions are reversible in solution, thereby representing an unprecedented reversible activation of a C=C bond by an antimony(I) compound. 相似文献
20.
René Milcent Anna Akhnazarian Nathalie Lensen 《Journal of heterocyclic chemistry》1996,33(6):1829-1833
A series of ethyl 2-oxo-3(2H)-benzoxazoleacetate derivatives 2 have been synthesized. By reaction with ammonia, primary amines or hydrazine, these compounds 2 were transformed into 1-(2-hydroxyphenyl)-2,4-imidazolidinedione derivatives 4, 5 and 6 , respectively. Some of these new hydantoins 4 , treated with phosphorus oxychloride, gave 3H-2-oxoimidazo[2,1-b]benzoxazole derivatives 9 . Ethyl 2-oxo-3(2H)-benzoxazolepropionate ( 10 ) was prepared by a Michaël reaction of ethyl acrylate with 2-benzoxazolone ( 1a ). With 10 , no cyclic transformation was observed in the presence of ammonia or alkylamine. 相似文献