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1.
3-(3-(tert-Butyldimethylsilyloxy)buta-1,3-dienyl)oxazolidin-2-one was reacted with several electrophilic 2H-azirines to give the expected cycloadducts in moderate to good yields. Treatment of the cycloadducts under acidic conditions gave six-membered ring aminoenones and aziridine derivatives. In the case where anilinium fluoride was used an inversion at the C-2 stereogenic center was observed forming an isomer of the former cycloadduct. The chiral (R)-3-(3-(tert-butyldimethylsiloxy)buta-1,3-dienyl)-4-phenyloxazolidin-2-one was also reacted with an electrophilic 2H-azirine. The reaction showed no diastereoselectivity, but both diastereoisomers were fully isolated by chromatography. 相似文献
2.
Vladimir CherkasovNikolay Druzhkov Tatiana KocherovaGeorgii Fukin Andrey Shavyrin 《Tetrahedron》2011,67(1):80-84
The interaction of 3,5-di-tert-butyl-o-benzoquinone with secondary amines has been studied. The synthetic procedure was developed in order to synthesize a series of new N,N-disubstituted o-aminophenols. The interaction of 3,5-di-tert-butyl-o-benzoquinone with dimethylamine leads to 2-(N,N-dimethylamino)-4,6-di-tert-butyl-phenol, which is oxidized in the reaction medium by the parent 3,5-di-tert-butyl-o-benzoquinone forming spirocompound 4,5′,6,7′-tetra-tert-butyl-3′-methyl-3′H-spiro[1,3-benzodioxol-2,2′-[1,3]benzoxazole]. 相似文献
3.
Ivan I. Stoikov Arkadiy Yu. Zhukov Maria N. Agafonova Ruzal R. Sitdikov Igor S. Antipin Alexander I. Konovalov 《Tetrahedron》2010,66(1):359-14064
A series of new p-tert-butyl thiacalix[4]arenes with o-, m-, p-amido and o-, m-, p-(amidomethyl)pyridine substituents at the lower rim in cone, partial cone, and 1,3-alternate conformations were synthesized. The ability of the obtained compounds to recognize the α-hydroxy (glycolic, tartaric) and dicarboxylic (oxalic, malonic, succinic, fumaric, and maleic) acids was investigated by UV-vis spectroscopy. Also, the efficiency and selectivity of binding, the association constants log Ka (102 to 107 M−1) and the stoichiometry were determined for the complexes of p-tert-butyl thiacalix[4]arenes with the acids. The receptors based on p-tert-butyl thiacalix[4]arenes with (amidomethyl)pyridine substitutes are most efficient in complexation in many cases. 相似文献
4.
Enrique Meléndez Vilmarí López Arnold L. Rheingold 《Journal of organometallic chemistry》2004,689(19):3082-3087
A series of Ru(acac)2(η4-diene) complexes containing cis- and trans-diene coordination have been investigated by cyclic voltammetry to correlate structural bonding and conformation patterns of diene ligands with redox behaviors. The solid-state structure of Ru(acac)2(2,3-dimethyl-1,3-butadiene) has been determined by single crystal X-ray diffraction methods. Ru(acac)2(2,3-dimethyl-1,3-butadiene) crystallizes in the monoclinic space group C2/c with a = 12.368(2) Å, b = 17.0600(2) Å, c = 16.0110(2) Å, β = 98.4405(10)° and V = 3341.38(10) Å3 for Z = 8. A structural comparison between several Ru-trans-η4-diene complexes and Ru-η4-1,3-cyclohexadiene revealed no difference in the Ru-C(diene) bond distances. However, through cyclic voltammetry experiments these species demonstrated different redox behavior, as function of the coordinated diene ligand. 相似文献
5.
Sergei V. Voitekhovich Pavel N. Gaponik Alexander S. Lyakhov Oleg A. Ivashkevich 《Tetrahedron》2008,64(37):8721-8725
A new method for the synthesis of 1,3,5-trisubstituted aminotetrazolium salts based on alkylation of 1- and 5-aminotetrazoles with the t-BuOH-HClO4 system is presented. Depending on the structure of the tetrazole substrate and reaction conditions, alkylation proceeds at the endocyclic nitrogen atoms as well as at the 1- and 5-amino groups giving mono-, di-, and tri-tert-butyl substituted tetrazolium salts. An X-ray diffraction investigation of 3-tert-butyl-1,5-bis(tert-butylamino)tetrazolium perchlorate and 5-amino-1,3-di-tert-butyltetrazolium chloride was carried out. 相似文献
6.
Christopher T. Brain 《Tetrahedron》2010,66(33):6613-6625
In the context of a proposed total synthesis of lankacidins, the synthesis of 4-(2-iodo-alkenyl)azetidinones and their participation in Stille coupling reactions have been investigated. 1-tert-Butyldimethylsilyl-4-(2-iodoethenyl)azetidinone was found to undergo a Stille coupling reaction with a 3-hydroxy-1-tributylstannylhepta-1,5-diene to give an acceptable yield of the corresponding conjugated diene but the analogous reaction with a 3-tert-butyldimethylsilyloxy-1-tributylstannylhepta-1,5-diene was unsuccessful. A series of 4-[(E)-2-iodoprop-1-enyl]azetidinones, a ring-opened ester and a lactone were also found to undergo Stille reactions with 3-tributylstannylprop-2-enol albeit with variable yields. Asymmetric syntheses of methyl (2R,3R,5S)-3-tert-butyldimethylsilyloxy-2-methyl-5-(2-trimethylsilylethoxy)methoxy-6-oxohexanoate, (3R,4S)-1-tert-butyldimethylsilyl-4-[(E)-2-iodoprop-1-enyl]-3-methylazetidin-2-one, and (5S,2E,6E)-5-tert-butyldimethylsilyloxy-2-methyl-1-phenylsulfonyl-7-tributylstannylhepta-2,6-diene and their incorporation into macrocyclic precursors of the lankacidins were then investigated. Key reactions were a Julia reaction between the aldehyde and the sulfone to form the 12,13-double-bond, a stereoselective acylation of the azetidinone, and formation of macrocycles using intramolecular Stille reactions in the presence of a free hydroxyl group at C(8) (lankacidin numbering). 相似文献
7.
The thermolysis of (3R,9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole-3-carboxylic acids in Ac2O led to novel 3-methylene-2,5-dioxo-3H,9bH-oxazolo[2,3-a]isoindoles and chiral (9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindoles were obtained on FVP. Starting from l-cysteine methyl ester (3R,10bR)-5-oxo-2,3-dihydro-10bH-[1.3]thiazolo[3,2-c][1,3]benzoxazines were obtained as single stereoisomers. The thermolysis of (3R,10bR)-5-oxo-2,3-dihydro-10bH-[1.3]thiazolo[3,2-c][1,3]benzoxazine-3-carboxylic acid in Ac2O gave 5-acetyl-2-phenyl-2,3-dihydrothiazole. The structures of methyl (3R,9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole-3-carboxylate 1a and methyl (2R,4R)-N-chlorocarbonyl-2-(2-hydroxyphenyl)thiazolidine-4-carboxylate 9 were determined by X-ray crystallography. 相似文献
8.
To improve the hydrophilicity of poly(styrene-b-isobutylene-b-styrene) (SIBS), this study focuses on the synthesis of novel functional ABA triblock copolymer thermoplastic elastomers (TPEs) with polyisobutylene (PIB) as rubbery segments. The precursor poly{(styrene-co-4-[2-(tert-butyldimethylsiloxy) ethyl]styrene)-b-isobutylene-b-(styrene-co-4-[2-(tert-butyldimethylsiloxy)ethyl]styrene)}(P(St-co-TBDMES)-PIB-P(St-co-TBDMES)) triblock copolymer was first synthesized by living sequential cationic copolymerization of isobutylene (IB) with styrene (St) and 4-[2-(tert-butyldimethylsiloxy) ethyl]styrene (TBDMES) using 1,4-di(2-chloro-2-propyl)benzene (DiCumCl)/titanium tetrachloride (TiCl4)/2,6-di-tert-butylpyridine (DtBP) as the initiating system. Then, P(St-co-TBDMES)-PIB-P(St-co-TBDMES) was hydrolyzed in the presence of tetra-butylammonium fluoride to yield poly{[styrene-co-4-(2-hydroxyethyl)styrene]-bisobutylene-b-[styrene-co-4-(2-hydroxyethyl)styrene]} (P(St-co-HOES)-PIB-P(St-co-HOES)) with pendant hydroxyl groups. P(St-co-HOES)-PIB-P(St-co-HOES) used as the paclitaxel carrier was also investigated in this study. Comparing with SIBS, P(St-co-HOES)-PIB-P(St-co-HOES) has exhibited better compatibility with paclitaxel and higher release rate. 相似文献
9.
Kozo Matsumoto Masaki Deguchi Minoru Nakano Hitoshi Yamaoka 《Journal of polymer science. Part A, Polymer chemistry》1998,36(15):2699-2706
Block polymerization of 1,1-diethylsilacyclobutane with styrene derivatives and methacrylate derivatives was investigated. Sequential addition of styrene to a living poly(1,1-diethylsilabutane), which was prepared from phenyllithium and 1,1-diethylsilacyclobutane in THF–hexane at −48°C, gave poly(1,1-diethylsilabutane)-b-polystyrene. Similarly, addition of 4-(tert-butyldimethylsiloxy)styrene to the living poly(1,1-diethylsilabutane) provided poly(1,1-diethylsilabutane)-b-poly(4-(tert-butyldimethylsiloxy)styrene). Poly(1,1-diethylsilabutane)-b-poly(methyl methacrylate) was obtained by treatment of living poly(1,1-diethylsilabutane) with 1,1-diphenylethylene followed by an addition of methyl methacrylate. Poly(1,1-diethylsilabutane)-b-poly(2-(tert-butyldimethylsiloxy)ethyl methacrylate) was also synthesized by adding 2-(tert-butyldimethylsiloxy)ethyl methacrylate to the living poly(1,1-diethylsilabutane) which was end-capped with 1,1-diphenylethylene in the presence of lithium chloride. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2699–2706, 1998 相似文献
10.
An innovative synthesis of aryl tethered 1,3-dimethylimidazo[4,5-b]pyrazin-2-ones 4 and 6 has been delineated through base catalyzed ring transformation of 6-aryl-4-(piperidin-1-yl)-2H-pyran-2-one-3-carbonitriles 1 and methyl 6-aryl-4-methylsulfanyl-2H-pyran-2-one-3-carboxylates 5 with 7-acetyl-1,3-dimethyllumazine 2 with subsequent ring contraction of the fused pyrimidine to an imidazole ring. An additional product, methyl [6-(1,3-dimethyl-2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyrazin-5-yl)-4-thiophen-2-ylpyran-2-ylidene]acetate 8b, was also isolated from the reaction of 5 and 2, as a minor constituent. 相似文献
11.
A concise synthesis of some new classes of heterocycles (4-aryl-11-oxo-1,2,3,11-tetrahydro-1,3a-diaza-cyclopenta[a]anthracen-6-carbonitriles and 5-aryl-12-oxo-1,3,4,12-tetrahydro-2H-1,4a-diazabenzo[a]anthracene-7-carbonitriles) has been developed by the ring transformation of suitably functionalized 2H-pyran-2-one with α-oxoketene cyclic aminals to intermediates (8-aroyl-5-aryl-2,3-dihydro-1H-imidazo[1,2-a]pyridine-7-ylidene)-acetonitriles and (9-aroyl-6-aryl-1,2,3,4-tetrahydropyrido[1,2-a]pyrimidin-8-ylidene)-acetonitriles) followed by their photocyclization either in CHCl3 or acetonitrile. This reaction was further explored for the synthesis of methyl 4-aryl-11-oxo-1,2,3,11-tetrahydro-1,3a,9-triaza-cyclopenta[a]anthracene-6-carboxylate, 4-aryl-11-oxo-1,2,3,11-tetrahydro-1,3a,9-triaza-cyclopenta[a]anthracene-6-carbonitriles, 5-aryl-12-oxo-1,3,4,12-tetrahydro-2H-1,4a,10-triazabenzo[a]anthracene-7-carbonitriles, 4-aryl-10-oxo-1,2,3,10-tetrahydro-9-thia-1,3a-diazadicyclopenta[a,g]naphthalene-6-carbonitriles and 5-aryl-11-oxo-1,3,4,11-tetrahydro-2H-10-thia-1,4a-diazacyclopenta[b]phenanthrene-7-carbonitriles from the similar reactions. 相似文献
12.
2,3-Bis(5-tert-butyl-2-methoxyphenyl)buta-1,3-diene was prepared by bromination of (Z)- and (E)-2,3-bis(5-tert-butyl-2-methoxyphenyl)-2-butene followed by treatment with zinc powder in a mixture of CH2Cl2 and acetic acid, which was converted to the corresponding o-terphenyl skeleton by the condensation with dimethyl acetylenedicarboxylate followed by oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone. 相似文献
13.
Vinod Kumar 《Tetrahedron letters》2006,47(9):1457-1460
Treatment of aldoximes with N-tert-butyl-N-chlorocyanamide gave hydroximoyl chlorides in quantitative yields in less than a minute, which on dehydrohalogenation in the presence of triethylamine gave the corresponding nitrile oxides. The nitrile oxides underwent 1,3-dipolar addition to dipolarophiles and gave 2-isoxazolines in excellent yields under mild conditions. 相似文献
14.
The gold(I)-catalyzed intramolecular hydroamination of cyclohexa-1,3-dienes bearing an arylsulfonamide at the C-5 position proceeds in a 1,4-addition manner to afford hexahydroindole derivatives in a diastereoselective fashion and in good yields, whereas octahydrocyclohepta[b]pyrrole derivatives can be obtained from seven-membered ring substrates under the same reaction conditions. Coordination of the gold(I) species to the 1,3-diene at the double bond adjacent to the arylsulfonamide tether gave an η2-alkene gold complex. The anti-attack of the sulfonamide to the η2-alkene gold complex at the terminal position of the 1,3-diene resulted in the formation of the fused bicyclic ring with a newly formed Au-C bond at the allylic position. Allylic rearrangement of the η1-allylgold complex followed by protodemetalation provided the fused heterobicyclic skeletons and regenerated the catalyst. 相似文献
15.
Treatment of dimethyl 4-(phenylsulfonyl)-4,5-hexadiene-1,1-dicarboxylate with potassium tert-butoxide in tert-butanol at room temperature effected successive endo-mode ring closure at the sp-hybridized carbon center and demethoxycarbonylation of the resulting malonate derivative leading to the exclusive formation of methyl 2-methyl-3-(phenylsulfonyl)-1-cyclopentenecarboxylate. An additional seven allenyl sulfones having a 1,3-dicarbonyl functionality gave the corresponding cyclopentene or cyclohexene derivatives in high yields. 相似文献
16.
J.S. Yadav P. Adi Narayana Reddy A. Suman Kumar A.R. Prasad B.V. Subba Reddy Ahmad Alkhazim Al Ghamdi 《Tetrahedron letters》2014
A stereoselective total synthesis of 4-((3S,5R)-3,5-dihydroxynonadecyl)phenol has been accomplished in two different synthetic approaches. In the first approach, Prins cyclization has been successfully utilized to produce the anti-1,3-diol unit, which was further converted into a required syn-1,3-diol through Mitsunobu reaction. The side chain was constructed through cross metathesis and hydrogenation sequence. In the second approach, the chiral syn-1,3-diol was prepared by a sequence of reactions such as alkylation of 1,3-dithane with (R)-epichlorohydrin, ring opening of the epoxide with vinylmagnesium bromide, and 1,3-syn-reduction of the β-hydroxyketone with NaBH4 in the presence of diethylmethoxyborane. 相似文献
17.
M. Yu. Moskalik V. V. Astakhova B. A. Shainyan 《Russian Journal of Organic Chemistry》2012,48(12):1530-1535
Reactions of trifluoromethanesulfonamide with cyclopentadiene, cyclohexa-1,3- and -1,4-dienes, cyclohepta-1,3,5-triene, and cycloocta-1,3-diene in the presence of t-BuOCl-NaI were studied. Trifluoromethanesulfonamide added at one double bond of cyclopentadiene and cyclohexa-1,3-diene in regio- and stereoselective fashion to give N-(5-iodocyclopent-2-en-1-yl)trifluoromethanesulfonamide and trans-N,N′-cyclohex-3-ene-1,2-diylbis(1,1,1-trifluoromethanesulfonamide), respectively. The reaction with cyclohexa-1,4-diene involved both isolated double bonds to produce N,N′-(2-chloro-5-iodocyclohexane-1,4-diyl)bis(1,1,1-trifluoromethanesulfonamide) which underwent halophilic reduction of the CHI group by the action of NaI and elimination of HCl, leading to N,N′-(cyclohex-2-ene-1,4-diyl)bis(1,1,1-trifluoromethanesulfonamide). Under analogous conditions, cyclohepta-1,3,5-triene was oxidized to benzaldehyde, while no reaction with trifluoromethanesulfonamide occurred. 相似文献
18.
1,3-Dipolar cycloaddition of 2-arylidene-6,7-dihydro-5H-thiazolo[3,2-a]pyrimidine-3(5H)-ones to diphenylnitrilimine (generated in situ by triethylamine dehydrohalogenation of the N′-phenylbenzohydrazonoyl chloride) proceeded regio- and site-selectively affording a mixture of two unexpected isomer products at reflux temperature. The cycloaddition/ring-opening/rearrangement/substitution, mechanism of the reaction was also discussed. 相似文献
19.
Novel p-tert-butyl thiacalix[4]arenes functionalized with hydrazide groups at the lower rim in cone, partial cone and 1,3-alternate conformations were synthesized and their receptor properties toward metal ions of p- (Al3+, Pb2+) and d- (Fe3+, Co3+, Ni2+, Cu2+, Ag+, Cd2+) elements were investigated by picrate extraction and dynamic light scattering (DLS). It was shown that the p-tert-butyl thiacalix[4]arenes functionalized with hydrazide groups are effective extractants of soft metal cations. The complex stoichiometry depended on the receptor configuration. All the p-tert-butyl thiacalix[4]arene derivatives with hydrazide fragments were able to form nanoscale aggregates but did not show self-association abilities. 相似文献
20.
Yukako Saito 《Tetrahedron letters》2010,51(52):6915-6917
The chemoselective O-tert-butoxycarbonylation of phenols using low levels (5-0.1 mol %) of 6,7-dimethoxyisoquinoline as a reusable organocatalyst is described. 相似文献