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1.
Bunnage ME Chippindale AM Davies SG Parkin RM Smith AD Withey JM 《Organic & biomolecular chemistry》2003,1(21):3698-3707
Conjugate addition of lithium dibenzylamide to tert-butyl (+/-)-3-methylcyclopentene-1-carboxylate occurs with high levels of stereocontrol, with preferential addition of lithium dibenzylamide to the face of the cyclic alpha,beta-unsaturated acceptor anti- to the 3-methyl substituent. High levels of enantiorecognition are observed between tert-butyl (+/-)-3-methylcyclopentene-1-carboxylate and an excess of lithium (+/-)-N-benzyl-N-alpha-methylbenzylamide (10 eq.) (E > 140) in their mutual kinetic resolution, while the kinetic resolution of tert-butyl (+/-)-3-methylcyclopentene-1-carboxylate with lithium (S)-N-benzyl-N-alpha-methylbenzylamide proceeds to give, at 51% conversion, tert-butyl (1R,2S,3R,alphaS)-3-methyl-2-N-benzyl-N-alpha-methylbenzylaminocyclopentane-1-carboxylate consistent with E > 130, and in 39% yield and 99 +/- 0.5% de after purification. Subsequent deprotection by hydrogenolysis and ester hydrolysis gives (1R,2S,3R)-3-methylcispentacin in > 98% de and 98 +/- 1% ee. Selective epimerisation of tert-butyl (1R,2S,3R,alphaS)-3-methyl-2-N-benzyl-N-alpha-methylbenzylaminocyclopentane-1-carboxylate by treatment with KO'Bu in 'BuOH gives tert-butyl (1S,2S,3R,alphaS)-3-methyl-2-N-benzyl-N-alpha-methylbenzylaminocyclopentane-1-carboxylate in quantitative yield and in > 98% de, with subsequent deprotection by hydrogenolysis and ester hydrolysis giving (1S,2S,3R)-3-methyltranspentacin hydrochloride in > 98% de and 97 +/- 1% ee. 相似文献
2.
Addition of (S)-(+)-tert-butyl 2-(iodomethyl)pyrrolidine-1-carboxylate to activated zinc, aryl halides, and a catalyst derived from Pd(2)(dba)(3) (2.5 mol %) and SPhos (5 mol %) in DMF allows trapping of the corresponding organozinc reagent, with formation of Boc-protected 2-benzylpyrrolidines (20-72%). 相似文献
3.
4.
M. Vorona I. Potoročina G. Veinberg I. Shestakova I. Kanepe M. Petrova E. Liepinsh E. Lukevics 《Chemistry of Heterocyclic Compounds》2007,43(5):646-652
The reaction of tert-butyl 7α-chloro-and 7-β-chloro-7α-isopropoxy-3-methyl-1,1-dioxoceph-3-em-4-carboxylates with the Vilsmeier
reagent was carried out with introduction of N,N-dimethylaminomethylene group at position 2 in the E-and Z-isomeric forms.
Prolonged treatment of tert-butyl 7α-chloro-3-methyl-2-(N,N-dimethylaminomethylene)-1,1-dioxoceph-3-em-4-carboxylate with
hydroxylamine hydrochloride in acetonitrile at 40–50°C gave tert-butyl 10(S)-chloro-6-methyl-5-oxa-1,1,9-trioxo-1-thia-4,8-diazatricyclo[7,2,0,02,6]undecane-7(R)-carboxylate which isomerized into 1-tertbutoxycarbonylmethyl-3α-chloro-4-(5-methylisoxazole-4-sulfonyl)azetidin-2-one.
In the case of tertbutyl 7β-chloro-7α-isopropoxy-3-methyl-2-(N,N-dimethylaminomethylen)-1,1-dioxoceph-3-em-4-carboxylate the
analogous reaction gave tert-butyl 10β-chloro-(2S,6S,7S,10R,11R)-10α-isopropoxy-6-methyl-5-oxa-1,1,9-trioxo-1-thia-4,8-diazatricyclo[7,2,0,02,6]undecane-7(R)-carboxylate, the struc-ture of which was determined by 2D-NOESY two-dimensional spectroscopy. The compounds
synthesized showed weak or no cytotoxic activity with respect to monolayers of cancer cells in vitro. 相似文献
5.
Bailey S Davies SG Smith AD Withey JM 《Chemical communications (Cambridge, England)》2002,(23):2910-2911
The asymmetric synthesis of (1R,2S,3R)-3-methyl-2-amino-cyclopentane carboxylic acid has been achieved via kinetic resolution of racemic tert-butyl 3-methyl-cyclopentene-1-carboxylate with homochiral lithium (S)-N-benzyl-N-alpha-methylbenzylamide. 相似文献
6.
P. S. Silaichev M. V. Dmitriev Z. G. Aliev A. N. Maslivets 《Russian Journal of Organic Chemistry》2010,46(2):255-259
Reactions of isopropyl 2-(1-aryl-4,5-dioxo-2-phenyl-4,5-dihydro-1H-pyrrol-3-yl)-2-oxoacetates with aromatic amines involve a pyrroledione-pyrroledione recyclization to form isopropyl 1-aryl-2-hydroxy-4,5-dioxo-3-[phenyl(arylamino)methylene]pyrrolidine-2-carboxylates.
The crystal and molecular structure of (Z)-isopropyl 2-hydroxy-4,5-dioxo-1-phenyl-3-[phenyl(phenylamino)methylene]pyrrolidine-2-carboxylate was proved by XRD analysis. 相似文献
7.
Revial G Lim S Viossat B Lemoine P Tomas A Duprat AF Pfau M 《The Journal of organic chemistry》2000,65(15):4593-4600
The Michael reaction of chiral 3-substituted secondary enaminoesters with 2-substituted nitroethylenes leads to (Z)-adducts, with good to excellent diastereoselectivity. The nitro group of these adducts was catalytically reduced to give, after cyclization and chiral amine elimination, pyrrolines or pyrrolidines after further reduction. In particular, the syntheses of ethyl (2R,3S,4S)-2,4-dimethylpyrrolidine-3-carboxylate and ethyl (2R,3R,4S)-2-(4-methoxyphenyl)-4-(3,4-(methylenedioxy)phenyl)pyrrolidine-3-carboxylate are described. 相似文献
8.
9.
[Ni3O(TBPLA)(H2O)](ClO4)4(H2O)6 [TBPLA=(S)-1,1′,1″-2,4,6-trimethylbenzene-1,3,5-triyl)-tris(methylene)-tris-(pyrrolidine-2-carboxylate)] was found to possibly display multiferroic property (the coexistence of ferroelectricity and ferromagnetism). The magnetic property of this compound was studied and no magnetic hysteresis loop was found probably due to an intrinsic fluctuation for the magnetic exchange energy. 相似文献
10.
Garrido NM El Hammoumi MM Díez D García M Urones JG 《Molecules (Basel, Switzerland)》2004,9(5):373-382
The asymmetric synthesis of the orthogonally funtionalised compounds tert-butyl 2-N-benzyl-N-alpha-methylbenzylamino-5-methoxycarbonylmethylcyclopentane- 1-carboxylate and methyl 2-N-benzyl-N-alpha-methylbenzylamino-5-carboxymethylcyclo- pentane-1-carboxylate by a domino reaction of tert-butyl methyl (E,E)-octa-2,6- diendioate with lithium N-alpha-methylbenzyl-N-benzylamide initiated by a Michael addition, subsequent 5-exo-trig intramolecular cyclisation and posterior selective hydrolysis with trifluoroacetic acid is reported. 相似文献
11.
Davies SG Garner AC Long MJ Smith AD Sweet MJ Withey JM 《Organic & biomolecular chemistry》2004,2(22):3355-3362
The double mutual kinetic resolution of tert-butyl (RS)-3-benzyl-cyclopentene-1-carboxylate with a 50 : 50 mixture of lithium (RS)-N-benzyl-N-alpha-methylbenzylamide and lithium (RS)-N-3,4-dimethoxybenzyl-N-alpha-methylbenzylamide gives, after protonation with 2,6-di-tert-butylphenol, a 50 : 50 mixture of the readily separable N-benzyl-(1SR,2RS,3RS,alphaRS)- and N-3,4-dimethoxybenzyl-(1SR,2RS,3RS,alphaRS)-beta-amino esters in >98% de in each case. This product distribution indicates that these amides react at very similar rates and with no mutual interference to furnish readily separable products, and are thus ideal for parallel kinetic resolution. The efficient parallel kinetic resolution (E > 65) of a range of tert-butyl (RS)-3-alkyl-cyclopentene-1-carboxylates with a pseudoenantiomeric mixture of homochiral lithium (S)-N-benzyl-N-alpha-methylbenzylamide and lithium (R)-N-3,4-dimethoxybenzyl-N-alpha-methylbenzylamide gives, after separation and N-deprotection, a range of carboxylate protected 3-alkyl-cispentacin derivatives in >98% de and >95% ee. 相似文献
12.
Investigations aimed at the enantioselective total synthesis of indolizidine 223A, a recently described 5,6,8-trisubstituted indolizidine alkaloid from a dendrobatid frog, are described. tert-Butyl (2R,3R)-3-amino-2-ethylhexanoate and its (2S,3R)-diastereomer, prepared in several steps from lithium N-benzyl-N-[(1R)-1-phenylethyl]amide and tert-butyl (2E)-hex-2-enoate by the Davies protocol, served as chiral building blocks from which two complementary suites of diastereomeric intermediates were made en route to pivotal tert-butyl 3-[2-(alkoxycarbonylmethylene)pyrrolidin-1-yl]-2-ethylhexanoate intermediates 20 and 21. Cyclisation of these enaminones, achieved by acid hydrolysis of the tert-butyl esters and activation of the liberated carboxylic acids as mixed anhydrides, afforded 6-ethyl-7-oxo-5-propyl-1,2,3,5,6,7-hexahydroindolizine-8-carboxylate esters 28 and 29. Several further transformations of these potential scaffolds for the synthesis of the target alkaloidal systems are also reported. 相似文献
13.
Barrett AG Ahmed M Baker SP Baugh SP Braddock DC Procopiou PA White AJ Williams DJ 《The Journal of organic chemistry》2000,65(12):3716-3721
4-Alkenyl-2-azetidinone systems were converted to the corresponding ethyl 2-?4-alkenyl-2-oxo-1-azetidinyl-4-pentenoates. In addition, 4-(2-propenyl-1-oxy)-, 4-(2-propenyl-1-thio)-, 4-?N-(2-propenyl)-(4-toluenesulfonyl)- and (3S, 4R)-4-(2-propenyl)-3-?(1R)-1-(tert-butyldimethylsilyloxy)ethyl-++ +azeti din-2-one were converted into beta-lactam dienes via sequential N-alkylation, Ireland-Claisen ester enolate rearrangement and esterification. Ring-closing metathesis using the Schrock ?(CF(3))(2)MeCO(2)Mo(=CHCMe(2)Ph)(=NC(6)H(3)-2,6-iso-Pr(2)) (1) or Grubbs Cl(2)(Cy(3)P)(2)Ru=CHPh (2) carbenes gave a series of ?5.2.0 and ?6.2.0 bicycles. Subsequent elaboration of the analogous (2R,7R, 8S)-tert-butyl 8-?(1R)-(tert-butyldimethylsilyloxy)ethyl-1-aza-9-oxobicyclo++ +?5.2. 0non-4-ene-2-carboxylate (15), via selenation and desilylation, gave (+)-(2S,7R,8S)-tert-butyl 8-?(1R)-hydroxyethyl-1-aza-9-oxobicyclo?5.2.0nona-2, 4-diene-2-carboxylate (18), a novel type of bicyclic beta-lactam. Diels-Alder cycloaddition further afforded tetracyclic systems exemplified by tert-butyl (1R,4S,5R,7S)-4-?(1R)-1-hydroxyethyl-3,9, 11-trioxo-10-phenyl-2,8,10,12-tetraazatetracyclo?5.5.2.0.(2, 5)0(8, 12)tetradec-13-ene-1-carboxylate (19). 相似文献
14.
M. Vorona G. Veinberg S. Belyakov M. Petrova E. Liepinsh E. Lukevics 《Chemistry of Heterocyclic Compounds》2008,44(4):486-493
By condensation of tert-butyl 3-methyl-7-oxoceph-3-em-4-carboxylate and its 3-acetoxymethyl analog with acetylmethylenetriphenylphosphorane
and 3-trimethylsilylpropyn-2-ylindenetriphenylphosphorane tert-butyl 7Z-acetylmethylene-3-methylceph-3-em-4-carboxylate and
also 7Z-and 7E-isomers of tert-butyl 3-acetoxymethyl-7-(3-trimethylsilylpropyn-2-ylidene)ceph-3-em-4-carboxylates were synthesized.
Oxidation of these compounds with 1 equivalent of meta-chloroperbenzoic acid gave their 1R-and 1S-sulfoxides, and oxidation
with 2 equivalents gave the corresponding sulfones. According to data from 1H NMR spectroscopy, the carbonyl of the β-lactam descreens proton H-9 of the alkylidene group in the 7Z-isomers more strongly
than in the 7E-isomers, shifting their signals to weaker field. Analogous shifts of the H-6 signal to weaker field was observed
in the 1R-sulfoxides in comparison with that for the 1S-sulfoxide. These results were confirmed by X-ray crystallography of
tert-butyl 7Z-acetylmethylene-3-methyl-1S-oxoceph-3-em-4-carboxylate and tert-butyl 7Z-acetylmethylene-3-methyl-1,1-dioxoceph-3-em-4-carboxy-late.
In memory of Professor A.A. Potekhin
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 618–626, April, 2008. 相似文献
15.
[reaction: see text] Lipase-catalyzed resolution of (2R*,3S*)-3-methyl-3-phenyl-2-aziridinemethanol, (+/-)-2, at low temperatures gave synthetically useful (2R,3S)-2 and its acetate (2S,3R)-2a with (2S)-selectivity (E = 55 at -40 degrees C), while a similar reaction of (2R*,3R*)-3-methyl-3-phenyl-2-aziridinemethanol, (+/-)-3, gave (2S,3S)-3 and its acetate (2R,3R)-3a with (2R)-selectivity (E = 73 at -20 degrees C). Compound (+/-)-2 was prepared conveniently via diastereoselective addition of MeMgBr to tert-butyl 3-phenyl-2H-azirine-2-carboxylate, (+/-)-1a, which was successfully prepared by the Neber reaction of oxime tosylate of tert-butyl benzoyl acetate 7a. The tert-butyl ester was requisite to promote this reaction. For determination of the absolute configuration of (2S,3R)-2a, enantiopure (2S,3R)-2 was independently prepared in three steps involving diastereoselective methylation of 3-phenyl-2H-azirine-2-methanol, (S)-10, with MeMgBr. The absolute configuration of (2S,3S)-3 was determined by X-ray analysis of the corresponding N-(S)-2-(6-methoxy-2-naphthyl)propanoyl derivative (S,S,S)-13. 相似文献
16.
Bunnage ME Burke AJ Davies SG Millican NL Nicholson RL Roberts PM Smith AD 《Organic & biomolecular chemistry》2003,1(21):3708-3715
Conjugate addition of homochiral lithium N-benzyl-N-alpha-methylbenzylamide to tert-butyl (E)-cinnamate or tert-butyl (E)-crotonate and in situ amination with trisyl azide results in the exclusive formation of the corresponding 2-diazo-3-amino esters in > 95% de. Amination of the lithium (E)-enolates of tert-butyl (3S,alphaR)-3-N-benzyl-N-alpha-methylbenzylamino-3-phenylpropanoate or tert-butyl (3S,alphaS)-3-N-benzyl-N-alpha-methylbenzylaminobutanoate with trisyl azide gives the (2R,3R,alphaR)- and (2S,3S,alphaS )-anti-2-azido-3-amino esters in good yields and in 85% de and > 95% de respectively. Alternatively, tert-butyl anti-(2S,3S,alphaS)-2-hydroxy-3-N-benzyl-N-alpha-methylbenzylaminobutanoate may be converted selectively to tert-butyl anti-(2S,3S,alphaS)-2-azido-3-N-benzyl-N-alpha-methylbenzylaminobutanoate by aziridinium ion formation and regioselective opening with azide. Deprotection of tert-butyl (2S,3S,alphaS)-2-azido-3-aminobutanoate via Staudinger reduction, hydrogenolysis and ester hydrolysis furnishes anti-(2S,3S)-diaminobutanoic acid in 98%, de and 98% ee. The asymmetric synthesis of the diastereomeric syn-(2R,3S)-diaminobutanoic acid (98% de and 98% ee) was accomplished via functional group manipulation of tert-butyl anti-(2S,3S,alphaS)-2-hydroxy-3-N-benzyl-N-alpha-methylbenzylaminobutanoate in a protocol involving azide inversion of tert-butyl (2S,3S)-2-mesyloxy-3-N-Boc-butanoate and subsequent deprotection. 相似文献
17.
采用实时红外技术对所合成的活性稀释剂吡咯烷基-N-甲酸-丙烯酸乙二醇酯的聚合动力学进行了测试.研究了光强、引发剂浓度及引发剂种类对其光聚合的影响.结果表明:光强越强、引发剂浓度越大,聚合速率越高,但是反应的最终双键转化率基本不变,均能达到100%左右.引发剂种类对其光聚合的最终双键转化率的影响不是特别明显,但对聚合速率有一定的影响. 相似文献
18.
Kumar B. Ravi Kumar A. Kishore Reddy B. Srinivas Shashikala K. Laxminarayana E. 《Russian Journal of Organic Chemistry》2022,58(4):580-583
Russian Journal of Organic Chemistry - tert-Butyl 4-[(E)-but-1-en-3-yn-1-yl]-3-{[tert-butyl(dimethyl)silyl]oxy}-1H-indole-1-carboxylate has been synthesized with a good yield and selectivity... 相似文献
19.
Metathesis reactions for the synthesis of ring-fused carbazoles 总被引:1,自引:0,他引:1
Pelly SC Parkinson CJ van Otterlo WA de Koning CB 《The Journal of organic chemistry》2005,70(25):10474-10481
[reactions: see text] The metathesis reaction is used as a key step for the synthesis of the indolo[2,3-a]carbazole core of rebeccamycin 13 and the sulfur analog of furostifoline 21. Using the same methodology for the attempted synthesis of furostifoline, we unexpectedly formed tert-butyl-2a-methyl-1,2,2a,10c-tetrahydro-6H-cyclobuta[c]furo[3,2-a]carbazole-6-carboxylate 26 from the unstable diene, tert-butyl 2-(2-isopropenyl-3-furyl)-3-vinyl-1H-indole-1-carboxylate 25, presumably via a spontaneous pi8 electrocyclization reaction. 相似文献
20.
Bhuvan Kulkarni Sharada Thimmappaiah Harisha Padigar Suchetan Parameshwar Adimule Naveen Shivalingegowda Lokanath Krishnappagowda Neratur Manjunatha Kumsi 《Research on Chemical Intermediates》2016,42(10):7375-7396
Two derivatives of N-Boc piperazine, an ester derivative, i.e., tert-butyl 4-(2-ethoxy-2-oxoethyl)-piperazine-1-carboxylate (1), and, a hydrazide derivative tert-butyl 4-(2-hydrazino-2-oxoethyl)piperazine-1-carboxylate (2) were synthesized and were characterized by FT-IR, 1H & 13C NMR and LCMS spectroscopic studies. The structures of both 1 and 2 were further confirmed by single crystal X-ray diffraction analysis. The molecule of 1 is linear in shape with the ethyl acetate moiety adopting fully extended conformation, while the molecule of 2 is L-shaped with the molecule being twisted at the C10 atom. The crystal structure of 1 adopts a two-dimensional zig-zag architecture featuring C–H…O intermolecular interactions, while that of 2 features strong N–H…O hydrogen bonds and intermolecular interactions of the type N–H…N and C–H…N, resulting in a two-dimensional structure. Furthermore, a detailed analysis of the intermolecular interactions and crystal packing of 1 and 2 via Hirshfeld surface analysis and fingerprint plots was performed. The antibacterial and antifungal activities of both the compounds have been studied against several microorganisms, and were found to be moderately active. 相似文献