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1.
The synthesis of the methyl esters of N-methoxycarbonyl- and N-benzyloxycarbonylaziridine-2-carboxylic acid 2 by reacting methyl 2-chloro-N-carbalkoxyglycinate 1 with diazomethane is described. The aziridines were readily converted to derivatives of O-methylserine 5 and S-methylcysteine 6. 相似文献
2.
The preparation of tryptophan derivatives through the Lewis acid promoted substitution of aziridine carboxylates with indole was found to be accompanied by a ring-expansion reaction to generate an oxazolidinone byproduct. The ratio of tryptophan to oxazolidinone products can be optimized through a judicious choice of Lewis acid and N-protecting group. 相似文献
3.
A. D. Shutalev 《Chemistry of Heterocyclic Compounds》1993,29(12):1421-1425
It is shown that the reaction of readily available 4,5-dihydroxyimidazolidin-2-ones with hydrazoic or p-toluenesulfinic acid takes place stereo- and regioselectively and leads to the formation of 4,5-diazido- or 4,5-di(p-tolylsulfonyl)imidazolidin-2-ones. The example of 4,5-diazidoimidazolidin-2-one is used to demonstrate the possibility of using compounds of this type for stereoselective introduction of substituents into the 4 and 5 positions of the imidazole ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1645–1649, December, 1993. 相似文献
4.
N-Tosyl aziridine-2-carboxylate methyl esters were prepared from methyl N-tosyl-l-serinate or N-tosyl-l-threoninate, tosyl chloride, and K2CO3, under phase-transfer catalysis (PTC) conditions. The same methodology, as applied to the tert-butyl N-tosyl-l-serine amide, afforded the corresponding newly prepared aziridine-2-carboxamide, as an enantiomerically pure compound. 相似文献
5.
[reaction: see text] A highly efficient carbonylative Suzuki-Miyaura coupling reaction of lactam-derived vinyl triflates and alkenylboronic acids afforded 2-(N-methoxycarbonylamino)-1,4-pentadien-3-ones as suitable substrates for the Nazarov reaction. The most competent Lewis acids for the Nazarov reaction were Cu(OTf)(2) (2 mol %) and Sc(OTf)(3) (3 mol %) in DCE, which provided the Nazarov products in excellent yield. As both the carbonylative coupling and the subsequent Nazarov reaction were high yielding, the overall methodology is a concise and efficient route to [1]pyrindine systems. 相似文献
6.
M. Hannoun M.
ini D. Kolbah F. Kajfe N. Bla
evi 《Journal of heterocyclic chemistry》1981,18(5):963-965
α-Haloacetanilides Ia-e react with hexamine in ethanol giving the bisimidazolidin-4-one derivatives IIa-e, which hydrolize, in acidic media into the corresponding mono-imidazolidin-4-ones IIIa-e. The compounds IIa-d were converted into 1,4-benzodiazepin-2-ones, under different conditions and in the presence of a variety of agents. The yields were between 50 and 100%. 相似文献
7.
A general approach to 6-phenylthio-substituted 2,3,4,5-tetrahydro-1H-1,3-diazepin-2-ones based on the ring expansion reaction of 1,2,3,4-tetrahydropyrimidin-2-ones under the action of nucleophiles has been developed. The first step of the synthesis was preparation of N-[(2-benzoyloxy-1-tosyl)ethyl]urea by three-component condensation of 2-benzoyloxyethanal, urea and p-toluenesulfinic acid. Nucleophilic substitution of the tosyl group in the obtained sulfone with sodium enolates of α-phenylthioketones followed by cyclization-dehydration, and debenzoylation gave 4-hydroxymethyl-5-phenylthio-1,2,3,4-tetrahydropyrimidin-2-ones which were transformed into the 4-mesyloxymethyl-derivatives. Treatment of the latter with nucleophilic reagents, such as NaCN, sodium diethyl malonate, PhSNa, MeONa, NaBH(4), sodium succinimide, or potassium phthalimide, afforded the target multi-functionalized diazepinones. The obtained 6-phenylthio-diazepinones and their 6-tosyl-substituted analogues were converted into 3-substituted 1-carbamoyl-1H-pyrroles under acidic conditions as a result of ring contraction. Effective one-pot synthesis of the latter from 4-mesyloxymethyl-pyrimidines was realized using a ring expansion/ring contraction sequence. 相似文献
8.
A short synthesis of alkyl 2-(bromomethyl)aziridine-2-carboxylates and alkyl 3-bromoazetidine-3-carboxylates was developed involving amination, bromination, and base-induced cyclization of alkyl 2-(bromomethyl)acrylates. These new small ring azaheterocyclic α- and β-amino acid derivatives are promising synthons as demonstrated by their transformation to 2-(aminomethyl)aziridine-2-carboxylates and 3-aminoazetidine-3-carboxylates. 相似文献
9.
Ring opening reaction of an enantiomerically pure aziridine-2-carboxylate with an azide nucleophile under aqueous acidic media proceeded efficiently and stereoselectively to give 3-amino-2-azidopropionate which is converted to orthogonally protected 2,3-diaminopropionate. 相似文献
10.
Emilie Centric Jacques Lauransan Christian Roussel Francesco A. Devillanova Gaetano Verani 《Journal of heterocyclic chemistry》1979,16(5):1083-1084
The hydrogen bonding abilities of iV-methylimidazolidin-2-one and -2-selone and thiazolidin-2-one and -2-selenone have been studied by ir spectroscopy at 25° in carbon tetrachloride solutions, using dimethyl sulphoxide and 4-chlorophenol as proton acceptor (KA) and proton donor (KB), respectively. The results are compared with those previously reported for N-methylimidazolidine-2-thione and thiazolidine-2-thione. The KA values increase in each series in the order O < S < Se and Kg in the reverse order. The and KB values are discussed in terms of the substituent in ring. The self-association constants (KD) are dependent on both KA and KB, although KA seems to be much more important. 相似文献
11.
Fu-Lin Chen 《Tetrahedron letters》2006,47(17):2899-2903
The first LiAlH4-driven reductive cyclization of the bifunctional 1-(methoxycarbonylmethyl)imidazolidin-4-ones, (−)-1a-c or(+)-1a-c, stereospecifically generated the corresponding 1,6-diaza-4-oxa-bicyclo[3.2.1]octanes, (−)-3a-c or(+)-3a-c, with a novel bicyclic system. 相似文献
12.
The rhodium-catalyzed reductive intramolecular ring expansion of N-(ethoxycarboxymethyl)oxazolidines was carried out under an atmosphere of carbon monoxide and hydrogen to afford N-methylmorpholin-2-ones in good to excellent yields. 相似文献
13.
A new strategy for the preparation of substituted imidazolidin-2-ones in two steps from readily available N-allylamines is described. Addition of the amine starting materials to isocyanates affords N-allylureas, which are converted to imidazolidin-2-one products with generation of two bonds and up to two stereocenters when treated with aryl bromides and catalytic amounts of Pd2(dba)3/Xantphos in the presence of NaO(t)Bu. [reaction: see text] 相似文献
14.
Yu. V. Tomilov G. P. Okonnishnikova E. V. Shulishov V. A. Korolev 《Russian Chemical Bulletin》2005,54(4):1052-1056
Prolonged storage (45–60 days) of N-methyl- or N-cyclopropylaziridine-2-carboxylates leads to their dimerization through the N—C(3) bond cleavage to form 1,3-disubstituted
2-methylimidazolidine-2,4-dicarboxylates in high yields. Prolonged storage of 1-benzyl-aziridine-2-carboxylate (like the reactions
of alkyl pyruvates with primary amines) results in cyclocondensation to yield 3-pyrrolin-2-one derivative.
Dedicated to Corresponding Member of the Russian Academy of Sciences E. P. Serebryakov on the occasion of his 70th birthday.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 1025–1029, April, 2005. 相似文献
15.
E. M. Afsah M. M. Abou-Elzahab M. T. Zimaity G. R. Proctor 《Monatshefte für Chemie / Chemical Monthly》1984,115(8-9):1065-1070
When -keto-ester1 a was reacted with dimethyl acetylenedicarboxylate ring expansion occurred to give substituted cyclooctadienones.Michael reactions of the title compounds1 with unsaturated ketones gave adducts, some of which underwent further cyclization reactions. A new route to -tetralone ring system10 via cyclization of the intermediateMichael adduct9 is described.
Michael- und Ringerweiterungsreaktionen von 6-Carboethoxy-3,5-diaryl-2-cyclohexen-1-onen
Zusammenfassung Bei der Reaktion von -Keto-ester1 a mit Dimethyl-acetylendicarboxylat wurden unter Ringerweiterung substituierte Cyclooctadienone erhalten. DieMichael-Reaktion der Titelverbindung1 mit ungesättigten Ketonen ergab Addukte, von denen einige weitere Cyclisierungsreaktionen eingingen. Es wird ein neuer Weg zum -Tetralonsystem10 über die Cyclisierung des intermediärenMichael-Addukts9 beschrieben.相似文献
16.
Lan-Ying Qin Andrew G. Cole Linda O’Brien Jin Wu Kai Xu Ian Henderson 《Tetrahedron letters》2009,50(4):419-806
A general solid-phase synthesis of 1,2,5-trisubstituted imidazolidin-4-ones is described. The key synthetic transformation incorporates a microwave-assisted condensation of an α-amino amide on solid support with an aldehyde in solution to give the corresponding resin-bound imidazolidin-4-one in a simple one-pot procedure. 相似文献
17.
Kyu Myung Lee Jong Chan Kim Philjun Kang Won Koo Lee Heesung Eum Hyun-Joon Ha 《Tetrahedron》2012,68(3):883-893
Preparation of functionalized 3,4-dihydroisoquinolines 17a–j from (S)-N-methoxy-N-methyl-1-[(R)-1-phenylethyl]aziridine-2-carboxamide 4 is an effective route for the synthesis of 3-(hydroxymethyl)-1,2,3,4-tetrahydroisoquinolin-4-ols. Stereoselective reduction of the cyclic imines 17a–j resulted in (1S,3S,4R)-4-(tert-butyldimethylsilyl-oxy)-3-[(tert-butyldimethylsilyloxy)methyl]-6,7-dimethoxy-1,2-disubstituted-1,2,3,4-tetrahydroisoquinolines and the desilylation of the TBS groups afforded (1S,3S,4R)-3-(hydroxymethyl)-6,7-dimethoxy-1,2-disubstituted-1,2,3,4-tetrahydroisoquinolin-4-ols 19a–i in good yields. Also, an asymmetric synthesis of novel tetracyclic 3-(hydroxymethyl)-1,2,3,4-tetrahydroisoquinolin-4-ols 23 and 25 was successfully achieved via Pd-catalyzed N-arylation and C–C coupling reaction. 相似文献
18.
Asymmetric Diels-Alder reactions with 2H-azirines as dienophiles have been studied. Diastereoselective reactions with an enantiopure azirine 1b, bearing a chiral auxiliary, gave substituted bi- and tricyclic tetrahydropyridines in high yield and stereoselectivity, under the influence of a Lewis acid. The novel enantioselective [4+2] cycloaddition reaction of 3-benzyl-2H-azirine carboxylate with cyclopentadiene was investigated with various chiral Lewis acid complexes and provided the corresponding tetrahydropyridines in moderate to low yield and enantioselectivity. 相似文献
19.
Smith K Conley N Hondrogiannis G Glover L Green JF Mamantov A Pagni RM 《The Journal of organic chemistry》2004,69(14):4843-4844
The mechanism for the unusual AlCl(3)-catalyzed rearrangement of 2,2-dichloronorbornane to 1-chloronorbornane in pentane has been elucidated; the reaction, which also yields four isomeric dichloronorbornanes, occurs in three steps: (1). ionization to form the 2-chloro-2-norbornyl cation, which was fully characterized by two-dimensional (1)H and (13)C NMR in SbF(5)/SO(2)ClF; (2). Wagner-Meerwein shift to yield the 1-chloro-2-norbornyl cation, which was partially characterized by (1)H NMR; and (3). hydride abstraction. 相似文献
20.
An interesting rearrangement of arylvinylidenecyclopropanes having three substituents at the 1- and 2-positions of the corresponding cyclopropane catalyzed by Lewis acids to give 6aH-benzo[c]fluorine derivatives via a double intramolecular Friedel-Crafts reaction or to give an indene derivative via an intramolecular Friedel-Crafts reaction is described. 相似文献