首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 156 毫秒
1.
The Stereoselective synthesis of cis and trans 2-methyl-1-phenyl-3-azabicyclo[3.1.0]hexanes and 1,2-diphen-yl-3-azabicyclo[3.1.0]hexanes from 2-oxo-1-phenyl-3-azabicyclo[3.1.0]hexane is described. The relative stereochemistry of the products was established by nuclear magnetic resonance and molecular modeling studies.  相似文献   

2.
A number of examples of the 6-azabicycIo[3.1.0]hexane ring system have been prepared by the oxidation of N-aminophthalimide or 3-amino-2-methyl-4-quinazoIone with lead tetraacetate in the presence of variously substituted cyclopentenes. Thus, 6-phthalimidyl-6-azabicyclo[3.1.0]hexane, dimethy 1–6-phthalimidyl-6-azabicyclo[3.1.0]-hexane-1,5-dicarboxylate, 2,3-benzo-6-phthalimidyl-6-azabicycIo[3.1.0]hexane and N-3-(2-methyl-4-quinazolyl)-6-azabicyclo [3.1.0]hexane were prepared for the first time. All of the new compounds were found to be stable in refluxing carbon tetrachloride and chlorobenzene. Refluxing 6-phthalimidyl-6-azabieyclo[3,1.0]hexane in acetic acid for 24 hours resulted in quantitative rearrangement to a phthalohydrazide, 8 .  相似文献   

3.
An unusual rearrangement of a 1-oxa-6-azaspiro[2.5]octane derivative giving access to novel 5-substituted 2-azabicyclo[3.1.0]hexanes is described. The synthetic application of the reaction is demonstrated by the synthesis of N-Boc-2,3-methano-β-proline. The amino acid was prepared through a three-step synthesis from easily available reagents in an overall yield of 15%.  相似文献   

4.
The reaction of benzyl-2-arylmethylidenecyclopropylmethyl-amine 1 with iodine in the presence of potassium carbonate or PhSeBr stereoselectively gives ring-closure product 1-iodo-2-aryl-3-azabicyclo[3.1.0]hexane or 1-phenylselenenyl-2-aryl-3-azabicyclo[3.1.0]hexane in good yields at room temperature. A plausible reaction mechanism has been proposed.  相似文献   

5.
Novel stereoselective synthesis of 3-azabicyclo[3.1.0]hexanes from allenenes is presented. Treatment of N-protected 4-alkyl-4-(N-allyl)amino allenes with allyl carbonate and a catalytic amount of Pd(2)(dba)(3).CHCl(3) in MeCN leads to stereoselective formation of the 3-azabicyclo[3.1.0]hexane framework in moderate to good yields. [reaction: see text]  相似文献   

6.
《Tetrahedron: Asymmetry》2000,11(19):3879-3882
Homochiral 7-oxa-2-azabicyclo[2.2.1]heptane and 8-oxa-6-azabicyclo[3.2.1]octane ring systems can be synthesized by reaction of specifically protected phosphoramidate derivatives of carbohydrates with (diacetoxyiodo)benzene or iodosylbenzene and iodine. The reaction mechanism goes through homolytic fragmentation of a hypothetical iodoamide intermediate. The N-radicals so generated participate in an intramolecular hydrogen abstraction reaction (IHA) to give the aforementioned bicycles.  相似文献   

7.
Both exo and endo isomers of (±)-methyl N-diphenylphosphoryl-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate and (±)-methyl N-diphenylphosphoryloxy-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate were dihydroxylated with OsO4. The unexpected formation of (±)-methyl 5,6-dihydroxy-N-diphenylphosphoryl-2-azabicyclo[2.2.1]heptane-3-endo-carboxylate from (±)-methyl N-diphenylphosphoryloxy-2-azabicyclo[2.2.1]hept-5-ene-3-endo-carboxylate is discussed based on NMR analyses and experimental observations. The two N-diphenylphosphoryl dihydroxybicycles are analyzed in terms of their crystalline structure by X-ray crystallography.  相似文献   

8.
Russian Journal of Organic Chemistry - 6-Aryl-2-(dicyanomethylidene)-4-oxo-3-azabicyclo[3.1.0]hexane-1,5-dicarbonitriles were synthesized by treatment of...  相似文献   

9.
Depending on the N-protecting group of pyroglutamates, the reactivity can be directed to the formation of 6-azabicyclo[3.2.1]octanes or 4-azabicyclo[3.3.0]octanes, which are conformationally restricted glutamate analogues.  相似文献   

10.
Synthesis of the model compounds of carzinophilin carrying 2-methylidene-1-aza-bicyclo[3.1.0]hexane systems was achieved. Formation of malonylidenes or N-acyl-glycinylidenepyrrolidines was carried out by utilizing Eschenmoser's sulfide contraction or Herdeis's condensation between the 2-methylthio-Δ1-pyrrolone derivatives and ethyl nitroacetate, respectively. The 1-azabicyclo-[3.1.0]hexane systems were constructed by base-promoted aziridine formation.  相似文献   

11.
P.S. Portoghese  D.T. Sepp 《Tetrahedron》1973,29(15):2253-2256
A facile route to 6-substituted 2-azabicyclo[2.2.1]heptanes via the novel tricyclic system, 2-azatricyclo[2.2.1.01,6]heptane (2), is described. The key intermediate (2) was prepared by oxidation of 4-aminomethylcyclopentene with lead tetra-acetate, and the bicyclic system was obtained by reaction of acetate with 2.MeI. Equilibration of exo- and endo-6-hydroxy-1-methyl-2-azabicyclo[2.2.1]heptane afforded an exo-endo isomeric ratio close to that of norborneol, and on this basis it is suggested that the steric requirements of the nitrogen lone pair are similar to that of CH.  相似文献   

12.
The synthesis of N-ethoxycarbonyl-7-azabicyclo[4.2.1]nonane and N-ethoxycarbonyl-9-azabicyclo[4.2.1]nonane, starting from bicyclo[5.1.0]octan-2-one, is described. The key step is the cyclopropyl ring fission by pyridinium chloride.  相似文献   

13.
Methyl- and phenyl-substituted N-(ethoxycarbonyl)-2-azabicyclo[2.2.0]hex-5-enes 6 were reacted with NBS in wet DMSO to afford bromohydrins. Mixtures of unrearranged 6-exo-bromo-5-endo-hydroxy-2-azabicyclo[2.2.0]hexanes 7a,b and rearranged 5-anti-bromo-6-anti-hydroxy-2-azabicyclo[2.1.1]hexanes 8a,b were formed stereoselectively from the parent alkene 6a and 4-methyl alkene 6b. The 5-methyl alkene 6c affords only unrearranged bromohydrin 7c and dibromohydrin 9. By contrast, solely rearranged 3-endo-substituted-2-azabicyclo[2.1.1]hexane bromohydrins 8d-f result from additions to 3-endo-methyl alkene 6d, 3-endo-4-dimethyl alkene 6e, and 3-endo-phenyl alkene 6f. As an alternative route to bromohydrins, the parent 5,6-exo-epoxide 10a and 5-endo-methyl-5,6-exo-epoxide 10b were ring opened with bromine/triphenylphosphine to afford unrearranged 5-endo-bromo-6-exo-hydroxy-2-azabicyclo[2.2.0]hexanes 11a,b, while the 3-endo-methyl epoxide 10c afforded solely the rearranged 5-anti-bromo-6-anti-hydroxy-3-exo-methyl-2-azabicyclo[2.1.1]hexane isomer 8g. Tributyltin hydride reduction of bromohydrins 7a,b and 11a afforded novel 2-azabicyclo[2.2.0]hexan-5-ols 13a,b and -6-ol 14, and bromohydrins 8a,b, 8d-g afforded new 2-azabicyclo[2.1.1]-hexan-5-ols 15a,b and 15d-g.  相似文献   

14.
Halogenation of 1-substituted 7-aryl-2,3,7-triazabicyclo[3.3.0]oct-2-ene-6,8-diones gives different products, depending on the substituent in position 1 (R1): when R1 = Ar, 6-chloro-3-azabicyclo[3.1.0]hexanes are formed, while compounds with R1 = H or Me give rise to 2- or 4-chloro-2,3,7-triazabicyclo[3.3.0]oct-2-ene-6,8-diones whose thermolysis leads to formation of the corresponding 6-chloro-3-azabicyclo[3.1.0]hexanes. Chlorination of 7-aryl-1,2,7-triazaspiro[4.4]non-1-ene-6,8-diones yields 3-chloro-1,2,7-triazaspiro[4.4]non-1-ene-6,8-diones, and thermolysis of the latter affords 1-chloro-5-azaspiro[2.4]heptanes.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 78–88.Original Russian Text Copyright © 2005 by Molchanov, Stepakov, Kostikov.  相似文献   

15.
Synthetic methods for 3-azabicyclo[3.1.0]hex-2-enes and 4-carbonylpyrroles have been developed that use copper-mediated/catalyzed reactions of N-allyl/propargyl enamine carboxylates under an O(2) atmosphere and involve intramolecular cyclopropanation and carbooxygenation, respectively. These methodologies take advantage of orthogonal modes of chemical reactivity of readily available N-allyl/propargyl enamine carboxylates; the complementary pathways can be accessed by slight modification of the reaction conditions.  相似文献   

16.
Grant R. Krow  Philip E. Sonnet 《Tetrahedron》2008,64(30-31):7131-7135
The regiochemical outcomes for s-BuLi/TMEDA deprotonations of N-Boc-2-azabicyclo[2.1.1]hexanes had been shown to be temperature dependent. Computational methods have been applied to advance understanding of the complexes that the reagents form, the character of the deprotonations, and hence the experimentally observed regiochemical biases. The tertiary anion is formed more readily than the secondary anion and is also the more stable anion. Computations for the enthalpy of proton abstraction from the analogous N-methoxycarbonyl structure also indicate greater stability for the tertiary carbamate anion.  相似文献   

17.
《Tetrahedron: Asymmetry》1999,10(12):2399-2410
The first synthesis of enantiomerically pure 2-azabicyclo[3.3.1]nonanes by an intramolecular radical reaction of the trichloroacetamido group bearing an (S)-N-1-phenylethyl substituent with the silyl enol ether moiety in compounds 7 is described. The procedure allows the two enantiomers of the 2-azabicyclo[3.3.1]nonane-3,6-dione, 3 and ent-3, to be prepared separately. β-Lactam 8 and normorphan 9 are also formed from 7 through an initial radical translocation process in the cyclization step.  相似文献   

18.
《Tetrahedron letters》1986,27(17):1913-1914
Pyrolysis of N-allyl enaminoesters is a general method for the stereoselective synthesis of 3-azabicyclo[3.2.0] heptenones ; the reaction involves a [2+2] intramolecular cycloaddition of an intermediate iminoketene.  相似文献   

19.
Electrolysis of arylidenemalononitriles and malononitrile in alcohols in an undivided cell in the presence of sodium bromide as mediator results in the stereoselective formation of (1R,2S,6R)*-6-aryl-2-amino-4,4-dialkoxy-1,5-dicyano-3-azabicyclo[3.1.0]hex-2-enes in 60-80% yields.  相似文献   

20.
The reactions of 6,6-dialkyl-5,7-dioxo-4,8-dioxaspiro[2.5]octane-1,1,2,2-tetracarbonitriles with primary aliphatic alcohols lead to the formation of alkyl 2,2,3,3-tetracyanocyclopropanecarboxylates; the reactions of the same compounds with ketone oximes give 2-amino-4,4-bis(alkylideneaminooxy)-6-(alkylidene-aminooxycarbonyl)-3-azabicyclo[3.1.0]hex-2-ene-1,5-dicarbonitriles, while with aldehyde oximes 2-amino-2-oxo-1,5-dicyano-3-azabicyclo[3.1.0]hex-2-ene-6-carboxylic acid is formed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号