共查询到20条相似文献,搜索用时 31 毫秒
1.
A. P. Molchanov A. N. Lykholai R. R. Kostikov 《Russian Journal of Organic Chemistry》2001,37(11):1517-1521
Ethyl diazoacetate adds to 1,3-diarylpropenones in a regioselective fashion to give intermediate 4,5-dihydro-3H-pyrazole derivative; 1,3-hydride shift in the latter leads to formation of isomeric ethyl 4-aryl- 5-aroyl-4,5-dihydro-1H-pyrazole-3-carboxylate and ethyl 4-aryl-3-aroyl-4,5-dihydro-1H-pyrazole-5-carboxylate at a ratio of 5:1. Thermolysis of these products is not stereospecific; as a result, three isomeric substituted ethyl cyclopropanecarboxylates and 2-pyranone derivative are formed. 相似文献
2.
Norton P. Peet Shyam Sunder Robert J. Barbuch 《Journal of heterocyclic chemistry》1980,17(7):1513-1518
An efficient, base-induced rearrangement of 2-[(1,2-dioxo-2-(methylamino)ethyl)phenylamino]benzoic acid methyl ester ( 7a ) to the isomeric 2-[(1,2-dioxo-2-(phenylamino)ethyl)methylamino]benzoic acid methyl ester ( 27a ) is described. This novel rearrangement must proceed through a spiro intermediate wherein benzoate is acting as a Michael receptor. When 2-[(1,2-dioxo-2-(methylamino)ethyl)methylamino]benzoic acid methyl ester ( 28 )-an oxamide which would produce a degenerate spiro intermediate — was subjected to rearrangement conditions, the product obtained was 1,3-dimethyl-2,4-(1H,3H)quinazolinedione ( 29 ). This latter transformation may have proceeded via a benzodiazepinetrione intermediate. 相似文献
3.
D. W. Rangnekar V. R. Kanetkar G. S. Shankarling J. V. Malanker 《Journal of heterocyclic chemistry》1999,36(1):15-16
Synthesis of ethyl 2-arylazo-4,9-dioxonaphtho[2,3-b]thiophene-3-carboxylate was achieved by diazotization of ethyl 2-amino-4,9-dioxonaphtho[2,3-b]thiophene-3-carboxylate and coupling with selected N,N-dialkylanilines. The key intermediate ethyl 2-amino-4,9-dioxonaphtho[2,3-b]thiophene-3-carboxylate was synthesized by the condensation of sodium salt of ethyl cyanoacetate with 2,3-dichloro-1,4-naphthoquinone. Ethyl 2-arylazo-4,9-dioxonaphtho[2,3-b]thiophene-3-carboxylate were applied on polyester fibers as disperse dyes and their dyeing properties were studied. 相似文献
4.
A potential inhibitor of gelation of sickle hemoglobin, 5-bromo-3-benzo[b]thienylalanine, has been synthesized along with several derivatives. Several hydrolytic pathways from the intermediate ethyl 5-bromo-3-benzo[b]thienylformamidomalonate have been examined, and that involving alcoholysis to ethyl N-formyl-5-bromo-3-benzo[b]thienylalanine shown to be superior. 相似文献
5.
G. A. Obanin A. S. Fokin Ya. V. Burgart O. V. Ryzhkov Z. E. Skryabina V. I. Saloutin O. N. Chupakhin 《Russian Chemical Bulletin》2000,49(7):1231-1236
Methods for the synthesis of the earlier unknownN-substituted 2-(5,6,7,8-tetrafluoro-4-oxo-1,4-dihydroquinolin-3-yl)glycoxylic acids their esters from copper chelate of ethyl
pentafluorobenzoylpyruvate were developed. The structure of intermediate ethyl 4-(R-amino)-2-oxo-3-pentafluorobenzoylbut-3-enoates
is discussed.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1234–1239, July, 2000. 相似文献
6.
Xin-Qiang Fang You-Cheng Liu Guan-Wu Wang Yu-Ping Ke 《Research on Chemical Intermediates》2006,32(7):603-611
Thermal reaction of ethyl (2Z)-4-bromo-2-cyano-3-(2-naphthyl)but-2-enoate (BCNB) with coenzyme NADH model 1-benzyl-1,4-dihydronicotinamide (BNAH) gives
the debrominated cyclized product (E)-1-cyano-2-methyl-2-(2-naphthyl)cyclopropane-1-carboxylate (1), debrominated olefinic products ethyl (2E)-2-cyano-3-(2-naphthyl)but-2-enoate (2) and ethyl (2Z)-2-cyano-3-(2-naphthyl)but-2-enoate (3). The formation of 1 proceeds via partial concerted hydride transfer and debromocyclopropanation, whereas the formation of 2 or 3 proceeds via an electron transfer-debromination-hydrogen abstraction mechanism. Nonetheless, they all derived from the same electron-transfer
intermediate complex. 相似文献
7.
Treatment of 4-[(3-hydroxy-2-pyridyl)amino]-2-phenyl-5-pyrimidinecarboxylic acid (X) with acetic anhydride under refluxing conditions afforded 10-hydroxy-2-phenyl-5H-pyrido[1,2-a]-pyrimido[4,5-d]pyrimidin-5-one acetate (IX). The intermediate X was prepared from 4-chloro-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester (V). The reaction of V with the sodium salt of 2-amino-3-hydroxypyridine at room temperature gave 4-(2-amino-3-pyridyloxy)-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester (VI). Treatment of VI with a hot aqueous sodium hydroxide solution and subsequent acidification gave X. Involvement of 4-[(3-hydroxy-2-pyridyl)amino]-2-phenyl-5-pyrimidinecaroboxylic acid ethyl ester (VIII) (Smiles rearrangement product) as an intermediate in the above alkaline hydrolysis reaction of VI to X was demonstrated by the isolation of VIII and its subsequent conversion into X under alkaline hydrolysis conditions. Acetylation of VIII with acetic anhydride in pyridine solution gave 4-[(3-hydroxy-2-pyridyl)amino]-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester acetate (XI), which afforded IX on fusion at 220°. This alternative synthesis of IX from XI supported the structural assignment of IX. Fusion of VI gave 10-hydroxy-2-phenyl-5H-pyrido[1,2-a]pyrimido]4,5-d]pyrimidin-5-one (VII). The latter was also obtained when VIII was fused at 210°. Acetylation of VII with acetic anhydride afforded IX. 相似文献
8.
Ethyl (6-phenyl-5,6-dihydroimidazo[2,1-b]thiazol-3-yl) acetate hydrobromide shows an allylic transposition in alkaline medium and gives ethyl (6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazol-3-ylidene)acetate. This compound possesses an exocyclic double bond which is stable upon acidification. The intermediate ethyl (2-imino-3-alkylthiazolin-4-yl)-acetates undergo an analogous transposition upon treatment with base, which is reversible upon acidification. These transpositions were observed in the pmr data. The steric constraint and π p π conjugation are discussed in this work. 相似文献
9.
Synthesis of the Pyrrolizidine Alkaloid (±)-Trachelanthamidine The important intermediate in the synthesis of the title compound 8 is the diastereoisomer mixture of ethyl 2-[2-(1,3 dioxolan-2-yl)ethyl]-5-oxopyrrolidine-3-carboxylate ( 3a/3b ) which was prepared from nitromethane, acrylaldehyde, and diethyl fumarate (Scheme). Its reduction (NaBH4, t-BuOH, MeOH) gave exclusively the trans-alcohol 4a , which was converted to the protected pyrrolidine derivative 6 . The deprotection and reduction of 6 gave the pyrrolizidine alkaloid 8 , characterized as its hydrochloride. 相似文献
10.
A. Mai M. Artico D. Rotili I. A. Novakov B. S. Orlinson M. B. Navrotskii A. S. Eremiichuk E. A. Gordeeva 《Russian Journal of Organic Chemistry》2009,45(10):1531-1534
A procedure has been proposed for the synthesis of 2-(cyclopentylsulfanyl)-6-[(1R)-1-(2,6-difluorophenyl) ethyl]-5-methylpyrimidin-4(3H)-one through intermediate (3R)-4,4-dimethyl-2-oxotetrahydrofuran-3-yl (2R)-2-(2,6-difluorophenyl)propanoate which was obtained from prochiral 2-(2,6-difluorophenyl)prop-1-en-1-one generated in situ. The proposed procedure may be regarded as stereoselective route to 6-[(1R)-1-(2,6- difluorophenyl)ethyl]-5-methylpyrimidin-4(3H)-one derivatives. 相似文献
11.
Yerrabelly Jayaprakash Rao Shailendara Dalal Yerrabelly Hemasri G. L. David Krupadanam 《Journal of heterocyclic chemistry》2019,56(4):1472-1477
A one‐pot synthesis of series of new ethyl‐7‐oxirane methyl‐2‐methyl‐5‐oxo‐5H‐benzopyrano[3,4‐c]pyridine‐1‐carboxylates ( 6a–e ) from 3‐allyl‐2‐hydroxy acetophenones ( 1a–e ) via key intermediate 8‐allyl‐4‐chloro‐3‐formyl coumarins ( 2a–e ) is described. The reaction involves Michael addition of 8‐allyl‐4‐chloro‐3‐formyl coumarins with ethyl 3‐amino crotonoate followed by cyclization, and per acid epoxidation proceeds under mild conditions and gives products in good‐to‐excellent yields. 相似文献
12.
The synthesis of scopin acetate ( 6b ) and 6,7‐didehydrohyoscyamine ( 17 ) was achieved by using tropine ( 5 ) as the starting compound. Formal (phenylthio)‐radical transfer to the nonactivated 6‐position of ethyl N‐demethyl‐3‐O‐(phenylthio)tropine‐N‐carboxylate ( 9 ) by irradiation in the presence of hexabutyldistannane is a key step of this synthetic approach, involving ethyl 6,7‐didehydro‐N‐demethyltropine‐N‐carboxylate ( 15 ) as a synthetic intermediate (Schemes 3 and 5). The reaction of 9 with tributylstannane in the presence of ethyl acrylate, as a radicophilic olefin, involves Michael‐type alkylation at C(6) of the tropine skeleton affording ethyl N‐demethyl‐N‐(ethoxycarbonyl)tropine‐6‐propanoate ( 18 ) (Scheme 6). 相似文献
13.
4-(2,6,10-Trimethyl-1,3,5,9-undecatetraenyl)benzoic acid (1) was synthesized starting from ethyl 4-formylbenzoate (2) and linalool. The key intermediate, ethyl 4-(2-methyl-3-oxo-1-propenyl)benzoate (5), was obtained by the addition of diethyl acetal (3), prepared from2, to ethyl 1-propenyl ether (EPE) followed by the hydrolysis of the resulting adduct.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 914–915, May, 1993. 相似文献
14.
Peter Wipf Roland Prevo Jost H. Bieri Gabriel Germain Heinz Heimgartner 《Helvetica chimica acta》1988,71(5):1177-1190
Thermal Generation and Reactions of (Benzylthio)-and (Arylthio)-Substituted Nitrile Ylides Thermolysis of 4-(benzylthio)- and 4-(arylthio)-1,3-oxazol-5(2H)-ones 6 , at 110–155° in the presence of dipolarophiles with activated C≡C, C?C, C?O, C?S, and N?N bonds, led to 5-membered cyclo-adducts and CO2 (cf. Schemes 3, 5-7). Heating 6a and 6c in the presence of ethyl propiolate yielded ethyl quinoline-3-carboxylate ( 19 ) and ethyl pyridine-3-carboxylate( 22 ), respectively (cf. Scheme 8). These results are rationalized on the basis of the intermediate formation of thio-substituted nitrile ylides of type 7 (cf. Scheme 2), which undergo regioselective 1,3-dipolar cycloadditions with reactive dipolarophiles. In the absence of such a dipolarophile, the nitrile ylides isomerize via a [1,4]-H shift to give 2-aza-1,3-butadienes of type 20 . The latter are trapped in a Diels-Alder reaction with ethyl propiolate (cf. Scheme 8). 相似文献
15.
A facile synthesis of 1,3,4-selenadiazolo[2,3-b]quinazoline derivatives via japp-klingemann reaction
Abdou O. Abdelhamid Hamdi M. Hassaneen Ahmad S. Shawali 《Journal of heterocyclic chemistry》1983,20(3):719-721
Diazotized anthranilic acid and its methyl ester react with ethyl α-selenocyanatoacetate 3a and α-selenocyanatoacetoacetanilide 3b to give in both cases the corresponding 1,3,4-selenadiazolo[2,3-b]quinazoline derivatives 7a and 7b , respectively, in good yields (70-80%). A mechanism is proposed and it is substantiated by an alternate synthesis of 7a and 7b from the corresponding hydrazidoyl chlorides 9a and 9b with potassium selenocyanate, respectively. An evidence for the involvement of the 1,3,4-selenadiazoline derivative as an intermediate in these reactions is provided by the isolation of 11 from either coupling of 3b with diazotized ethyl p-aminobenzoate or the reaction of hydrazidoyl chloride 12 with potassium selenocyanate. 相似文献
16.
The reaction of aroyl chlorides 1 with KSeCN and ethyl diazoacetate ( 6 ) in acetone at room temperature yields ethyl 2‐aroyl‐5‐(aroylimino)‐2,5‐dihydro‐1,2,3‐selenadiazole‐4‐carboxylates 7 (Scheme 3). A reaction mechanism via the initial formation of the corresponding aroyl isoselenocyanates 2 followed by a 1,3‐dipolar cycloaddition of the diazo compound with the C=Se bond to give ethyl 5‐(aroylimino)‐4,5‐dihydro‐1,2,3‐selenadiazole‐4‐carboxylates of type D is proposed. Acylation of the latter at N(2) leads to the final products 7 . Deacetylation of 7 to give ethyl 5‐(aroylimino)‐1,2,3‐selenadiazole‐4‐carboxylates 10 is achieved by treatment of 7 with morpholine (Scheme 5). The intermediate isoselenocyanates 2 partially oligomerize to give two different oligomers. The symmetrical one reacts with morpholine to yield selenourea derivatives 12 (Scheme 6). 相似文献
17.
Robert J. Maleski C. Edward Osborne Sharon M. Cline 《Journal of heterocyclic chemistry》1991,28(8):1937-1939
2(3H)-Benzoxazolones 3 can be prepared directly from the corresponding 2-aminophenols and phenyl chloroformate. The intermediate 2-hydroxy phenylcarbamates 2 are formed easily in aqueous alcohol solvent and these are converted rapidly to product, without their isolation, using one equivalent of sodium hydroxide. The synthesis accommodates a wide variety of substituents, including the easily hydrolyzed ethyl ester. 相似文献
18.
Grzegorz Mlostoń Katarzyna Urbaniak Anthony Linden Heinz Heimgartner 《Helvetica chimica acta》2012,95(4):577-585
The attempted ethenylation at C(2) of 2‐unsubstituted 1H‐imidazole N‐oxides with ethyl acrylate (=prop‐2‐enoate) in the presence of Pd(OAc)2 does not occur. In contrast to the other aromatic N‐oxides, the [2+3] cycloaddition of imidazole N‐oxides predominates, and 3‐hydroxyacrylates, isomeric with the cycloadducts, are key products for the subsequent reaction. The final products were identified as dehydrated 2+1 adducts of 1H‐imidazole N‐oxide and ethyl acrylate. The role of the catalyst is limited to the dehydration of the intermediate 3‐hydroxypropanoates to give 1H‐imidazol‐2‐yl‐substituted acrylates. 相似文献
19.
Tetsuji Kametani Kazuo Kigasawa Mincharu Hiiragi Kikuo Wakisaka Nagatoshi Wagatsuma Osamu Kusama Tsunco Urya 《Journal of heterocyclic chemistry》1973,10(6):999-1005
1,2,3,4,5,6-Hexahydro-8-hydroxy-2,6-methano-3,6,1 1-trimethyl-2,3-benzo |g| diazocine (IV) and 1,2,3,4,5,10,11,12-octahydro-7-hydroxy-1,5-dimethylpyridazino |2,3-b| isoquinoline (VI) were synthesized from a common intermediate, 3-(3-methoxyphenyl)-2-butanone (VII), through several steps. Reaction of VII with ethyl bromoacetate gave the mixture of ethyl 4-keto-3-(3-methoxyphenyl)-3-methylpentanoate (XIV) and ethyl 4-keto-5-(3-methoxyphenyl)hexanoate (XV) which were hydrolyzed and condensed with methylhydrazine to give the 4,5-dihydro-5-(3-methoxyphenyl)-2,5,6-trimethyl- (XVIII) and 4,5-dihydro-6-(3-methoxy-α-methylbenzyl)-2-methylpyridazine-3(2H)one (XIX). Reduction of XVIII and XIX followed hy cyclization afforded the 2,3-benzo |g| diazocine (XXII) and the pyridazino |2,3-b| isoquinoline (XXIII) which on treatment with 47% hydrobromine acid afforded the phenolic bases (IV and VI), respectively. The mass spectrum of IV, VI, XXII and XXIII was also discussed. 相似文献
20.
Carl B. Ziegler Daniel B. Moran Thomas J. Fenton Yang-I. Lin 《Journal of heterocyclic chemistry》1990,27(3):587-589
A one-pot synthesis of ethyl 8,9-difluoro-6-oxo-6H-benzo[c]quinolizine-5-carboxylate 11 has been developed. The condensation of ethyl 2-pyridylacetate and 2,4,5-trifluorobenzoyl chloride followed by intramolecular nucleophilic aromatic substitution gave the desired ring system. This intermediate was converted to the title compound and its in vitro biological activity is reported. 相似文献