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1.
2.
Brown's DCME reaction was successfully performed employing B-alkyl-9-oxa-10-borabicyclo[3.3.2]decanes (1) to provide carboxylic acids (2) in good to excellent yields with complete retention of configuration.  相似文献   

3.
The reaction of an α-chloroglycinate ester with the dimethylaluminum acetylide derivative of phenyl propargyl ether provides the corresponding 5-vinyloxazole in 40-50% yield.  相似文献   

4.
We synthesized hetero-Diels-Alder cycloadducts from acyl nitroso derivatives and 9,10-dimethylanthracene, to be photo-inducible HNO-releasing agents and found that introduction of conjugated nitroaromatic groups effectively enhanced the responsiveness of HNO release to UV-A irradiation; we confirmed photoinduced HNO formation by EPR and GCMS analysis.  相似文献   

5.
Readily available [4 + 3]-cycloadducts derived from trapping of the Nazarov 2-oxidocyclopentenyl cation with 2,3-dimethyl-1,3-butadiene are cleaved by ozonolysis to furnish triketones. In the presence of methanolic KOH, these triones undergo tandem aldol additions to furnish centro-hydroxylated triquinacene skeletons.  相似文献   

6.
2-Alkynylbenzaldoxime reacts with amine catalyzed by silver triflate under mild conditions, leading to 1-aminoisoquinolines in good yield. This reaction proceeds efficiently with good functional group tolerance.  相似文献   

7.
Li C  Zhang T  Zeng Z  Liu X  Zhao Y  Zhang B  Feng Y 《Organic letters》2012,14(2):479-481
One new route for the synthesis of amino-substituted indazol-3,5-dione via the amidation reaction of o-carboxyazobenzenes is reported. Optimization which includes effects of the solvents, molar ratio of starting materials, and dehydrating agents on this reaction has been studied. A possible reaction mechanism has been proposed on the basis of the product's structure, and the steric hindrance could be the main reason for low yield.  相似文献   

8.
R.K. Hill  T. Yuri 《Tetrahedron》1977,33(13):1569-1571
Application of the Mundy N-acyllactam rearrangement to 6 - methyl - 2 - piperidone has led to a synthesis of optically active dihydropinidine, confirming the absolute configuration of the pine alkaloid pinidine, and to a new synthesis of the fire ant toxin, Solenopsin A.  相似文献   

9.
Base-catalyzed reaction of 5-acylmethyl-2,5-di-t-butyl-4-oxa-2-cyclopentenones selectively derived from 4-alkyl-2,6-di-t-butylphenols via three steps involving oxygenation, acetylation, and acid-treatment gave 3-alkyl-2,5-di-t-butyl-2,4-cyclopentadienones in excellent yield.  相似文献   

10.
《Tetrahedron letters》1987,28(39):4529-4532
Cycloadditions of (E)-1-N-carbobenzoxyamino-1,3-butadiene to naphtoquinones followed by aromatization of the adducts and deprotection of the amino group afford regioselective syntheses of −5 and −8 substituted aminoanthraquinones.  相似文献   

11.
12.
丁新腾  葛羽  滕铸  范君瑶 《化学学报》1987,45(11):1138-1139
研究了用镁对3-氯-2-烃基四氢吡喃(1)的开环反应,制得一系列5-烃基-4-戊烯-1-醇(2),上述反应产率高,立体选择性强,无论顺式或反式的(1)开环时都得到反式(2).  相似文献   

13.
A simple route to 1-R-3-(2-indolyl)-1-propanones has been elaborated based on recyclization of 2-(2-aminobenzyl)furan derivatives. Being a modification of the Reissert indole synthesis, our approach employs the furan ring as a source of carbonyl function. This approach is general and allows varying of substituents in aromatic ring as well as in 3-position of indole nucleus.  相似文献   

14.
New substituted 2-amino-3-cyano-4H-pyrans have been studied by electron ionization (EI), chemical ionization (CI) and electrospray ionization (ESI) mass spectrometry. The retro-Diels-Alder reaction (RDA) is the main fragmentation pattern observed in the EI spectra forming an unsaturated ketone as the diene fragment. In contrast, a different RDA reaction takes place yielding an unsaturated amide as diene fragment together with the unsaturated ketone in the CI spectra. The MS/MS spectra obtained using an ESI source reveal that the favoured fragmentation by collision induced dissociation (CID) is the elimination of the substituent at the C4 position with formation of a stable pyrilium cation.  相似文献   

15.
Butadiene cation radicals are produced symmetrically from the ring and side-chain of the vinylcyclohexene cation radical near the onset of the fragmentation. The appearance energies of C4H6+? and C4H2D4+? from (3,3,6,6-D4)vinylcyclohex ene were measured as 11.07 ± 0.05 and 11.06 ± 0.06 eV, respectively. This sets the barrier to retro-Diels-Alder decomposition at 1140 kJ mol?1 above the energy of 1 and 44 kJ mol?1 above the thermochemical threshold corresponding to C4H6+? + C4H6. Topological molecular orbital calculations indicate that this lowest-energy path involves a sequential rupture of the C3C4 and C5C6 bonds, with a calculated barrier of 211 kJ mol?1. The second, two-step reaction channel proceeds by subsequent fission of the C5C6 and C3C4 bonds with a barrier of 299 kJ mol?1. This channel is found experimentally as a break on the ionization efficiency curve at 12.1 eV. Both the supra-supra and the supra-antara pericyclic reactions go through energy maxima and are therefore forbidden. The supra-supra process is the most favorable route for decomposition from the first excited state, the activation energy being 333 kJ mol?1. The preference for the two-step mechanism is due to hyperconjugative stabilization of intermediate molecular configurations.  相似文献   

16.
[reaction--see text] Dimerization of salicylaldehydes provided 6H,12H-6,12-epoxydibenzo[b, f][1,5]dioxocins in multigram quantities. Deprotonation-allylation of the benzylic acetals followed by further functionalization of the diallyl derivative and double Friedel-Crafts cyclization gave a novel preussomerin analogue which possessed the full carbon skeleton of the natural products.  相似文献   

17.
Chen Z  Zheng D  Wu J 《Organic letters》2011,13(5):848-851
A copper-catalyzed three-component reaction of 2-ethynylaniline, sulfonyl azide, and nitroolefin is reported. This reaction generates functionalized indoles in good yields and proceeds smoothly under mild conditions. Some hits as an HCT-116 inhibitor are found from the preliminary biological screening.  相似文献   

18.
Zhu J  Kell AJ  Workentin MS 《Organic letters》2006,8(22):4993-4996
Maleimide-modified monolayer-protected gold nanoparticles (MPGN) are prepared from the protected furan-maleimide via the thermally reversible Diels-Adler reaction when required. These maleimide-MPGNs serve as a general platform allowing for a Diels-Alder reaction with furan-modified MPN to prepare larger 3D networks reversibly. [reaction: see text]  相似文献   

19.
A general approach to the regio- and stereoselective total synthesis of the benanomicin-pradimicin antibiotics (BpAs) is described. Construction of the aglycon has been achieved by 1) the diastereoselective ring-opening of a biaryl lactone by using (R)-valinol as a chiral nucleophile and 2) the stereocontrolled semi-pinacol cyclization of the aldehyde acetal by using SmI(2) in the presence of BF(3)OEt(2) and a proton source to afford the ABCD tetracyclic monoprotected diol. This strategy enabled us to control the two stereogenic sites in the B ring (C-5 and C-6) and the regioselective introduction of the carbohydrate moiety. The ABCD tetracycle could serve as an ideal platform for the divergent access to various BpAs. The amino acid (D-alanine) was introduced onto the ABCD tetracycle. Glycosylation was promoted by the combination of Cp(2)HfCl(2) and AgOTf (1:2 ratio). Construction of the E ring followed by deprotection completed the first total synthesis of benanomicin A (2 a), benanomicin B (2 b), and pradimicin A (1 a). The route is flexible enough to allow the synthesis of other congeners differing in their amino acid and carbohydrate moieties.  相似文献   

20.
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