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1.
In view of the versatile chemistry and important applications of organoselenium compounds, the introduction of selenium and oxygen functionalities to 1,4-dihydropyridines 4a–d has been achieved. Thus, the natural tendency of 1,4-dihydropyridines 4a–d to undergo biomimetic oxidation to afford pyridinium salts can be switched off through the use of reagents that interact electrophilically with the enamine moiety present in the system. Electrophilic interaction of N-phenylselenophthalimide (N-PSP) with N-alkyl-1,4-dihydropyridines 4a–d in the presence of tetrahydrofuran/H2O and alcohol (methanol or ethanol) stereoselectively leads to the corresponding trans-2-hydroxy (or alkoxy) 3-phenylseleno-1,2,3,4-tetrahydropyridines 5a–k in satisfactory yields (40–90%).
2.
Chad A. Snyder Nathan C. Tice Phenahas G. Sriramula James L. Neathery Justin K. Mobley Chad L. Phillips 《合成通讯》2013,43(9):1357-1369
Pyridazines are an important class of heterocyclic compounds as a result of their materials and commercial applications. The synthesis of 5,6-fused ring pyridazines 2a–h from 1,2-diacylcyclopentadienes (fulvenes) 1a–h is described herein. This route was quite general, and features an efficient and convenient two-step synthesis of a series of 5,6-fused ring 1,2-disubstituted pyridazines using enolized 1,2-disubstituted fulvenes in a methanolic solution of hydrazine. Full characterization of newly formed fulvene 1e and pyridazines 2a–h are reported. Single-crystal X-ray analysis confirms the molecular structure of pyridazine 2f, which displayed the expected pyridazine fused to the cyclopentadienyl moiety. Adding to their real world capabilities in electronic devices, compounds 2a–h display reasonably high stability in solution and in air at room temperature.
3.
A versatile class of 2-aminopyrroles containing various electron-withdrawing substituents at the 3-position have been N-arylated on the amine using a palladium-catalyzed cross-coupling reaction. Using this methodology, a pyrimidone-based tricyclic system has been prepared in just one step from a starting 2-aminopyrrole.
4.
Reactions of (N-isocyanimino)triphenylphosphorane with aromatic bis-aldehydes (isophthalaldehyde and terphthalaldehyde) in the presence of aromatic (or heteroaromatic) carboxylic acids proceed smoothly at room temperature and in neutral conditions to afford sterically congested 1,3,4-oxadiazole derivatives in good yields. The reaction proceeds smoothly and cleanly under mild conditions, and no side reactions were observed.
5.
G. C. M. Kondaiah M. Vivekanandareddy L. Amarnath Reddy Smita V. Anurkar V. M. Gurav M. Ravikumar 《合成通讯》2013,43(8):1186-1191
An asymmetric synthesis of (S,S,S)-2-aza-bicyclo-[3.3.0]-octane-3-carboxylic acid benzyl ester 2 as an intermediate of angiotensin converting enzyme (ACE) inhibitor, ramipril 1, is described.
6.
A simple and convenient two-step method for the synthesis of the title compound 1 was developed using N-protected 4-pyrazolilmagnesium bromide 9 as a key intermediate. Laborious procedures for purification or isolation of target compound are not required, therefore, up to 20 g of 1 could be obtained in a single run.
7.
A protocol has been developed for the synthesis of the linear naphthopyran 16, by the TiCl4-catalyzed isomerization of 2,5-dimethyl dioxolane 1, having a methoxy group at position 1′ and a bromine atom at position 4′ of the naphthyl precursor to favor isomerization at position 2′.
8.
Mahantesha Basanagouda 《合成通讯》2013,43(17):2569-2582
A novel method for the synthesis of 2-phenyl-5-(o-hydroxyphenyl)-pyridazin-3(2H)-ones and 5-(o-hydroxyphenyl)-pyridazin-3(2H)-ones has been found during the reaction of 4-bromomethylcoumarins with phenylhydrazine and hydrazinehydrate, respectively, under controlled alkaline conditions.
9.
The indium-mediated Barbier-type allylation reaction of aldehydes with allyl bromide, which gives corresponding homoallyl alcohols, was investigated. The reaction medium and the effects of substituents were discussed in detail. The results showed that various aldehydes, including aromatic, heterocyclic, and aliphatic aldehydes, with different substituents could all react well with excellent yields of 91–97% in aqueous tetrahydrofuran at room temperature within about 1 h.
10.
Daniel R. Zuidema Sarah L. Williams Katherine J. Wert Karin J. Bosma Abigail L. Smith Robert C. Mebane 《合成通讯》2013,43(19):2927-2931
Aryl ketones are readily deoxygenated to their corresponding aryl alkanes upon treatment with Raney nickel catalyst in boiling 2-propanol.
11.
A simple and efficient method has been developed for the synthesis of sulfonamide phosphonates from N-tosyl aldimines and dimethyl trimethylsilyl phosphite at 0 °C in the presence of Amberlyst-15 as a heterogeneous catalyst.
12.
The dehydration of aldoximes and amides, and oxidation of benzoin are accomplished in one-pot using in situ–generated Burgess-type reagent.
Keywords: Amide, benzil, benzoin, Burgess reagent, Burgess-type reagent, dehydration, nitrile, oxidation, oxime
13.
Oleksandr P. Dacenko Olga V. Manoylenko Pavel K. Mykhailiuk Dmitriy M. Volochnyuk Oleg V. Shishkin 《合成通讯》2013,43(7):981-992
An improved synthesis of Boc-monoprotected 5- and 6-amino-2-azanorbornanes is reported. The synthetic scheme consists of five steps and allows multigram quantities of the title compounds to be obtained. The regio- and stereochemistries of the products are established by two-dimensional NMR experiments.
14.
The synthesis of benzimidazoles has been achieved in a one-pot reaction in excellent yield using a newly developed methodology. 2,5-Disubstituted-3-cyanoacetyl indoles were directly condensed with substituted orthophenylenediamine via microwave irradiation under neat, solid support, and conventional conditions in a short time to afford the corresponding products in good yields. Structures of the products thus obtained were confirmed by their melting points, infrared, 1H NMR, 13C NMR, and mass spectral data.
15.
Jong Taik Moon Jin Ah Jung Sung Hoon Ha Sung Ho Song Sung Jun Park Jungahn Kim 《合成通讯》2013,43(9):1282-1292
A formal asymmetric synthesis of (+)-3-demethoxyerythratidinone (1) is reported using the key intermediate 3 as the starting material, which is available from L-malic acid by a known method.
16.
Organic ammonium tribromide (OATB), N-methylpyrrolidine-2-one hydrotribromide (MPHT) was found to be an efficient catalyst for the regioselective ring opening of epoxides with various nucleophiles under solvent free conditions. This procedure occurs under neutral and mild reaction conditions with out adding any additive and afforded high yields of products.
17.
Tetrazoles were introduced into cyclotriphosphazenes to obtain hexakis-(4-tetrazolylphenyloxy)cyclotriphosphazene (2) in good yield (88.9%) by reacting hexakis-(4-cyanophenyloxy)cyclotriphosphazene (1) with sodium azide in N,N-dimethylformamide (DMF) in the presence of NH4Cl as a catalyst. Its alkylonitrile derivative, hexakis-(4-cyanoethyltetrazolylphenyloxy)cyclotriphosphazene (3), was prepared by the reaction of 2 with acrylonitrile in acetonitrile, using triethylamine as a catalyst.
18.
Synthesis of dibenzoxanthenes through condensation of β-naphthol with various aromatic and aliphatic aldehydes in ethanol as an ecofriendly solvent using RuIII as catalyst is reported.
19.
Hassan Zali Boeini 《合成通讯》2013,43(19):2932-2938
1,3-Dibromo-5,5-diphenylimidazolidine-2,4-dione (N,N’-dibromo phenytoin) was efficiently used for the rapid conversion of thiobenzamides to the corresponding 3,5-diaryl-1,2,4-thiadiazoles in water–wet paste conditions. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.
20.
An efficient chemoenzymatic route to S-betaxolol is reported. A strain (Rhodotorula mucilaginosa DQ832198) screened from soil was used as biocatalyst for the kinetic resolution of the key acetylated intermediates. Excellent enantiomeric excess (ee > 99%) was obtained under very mild conditions. The biocatalyst is quite stable and could be used several times with little decrease of the resolving ability.