A direct approach to α-hydroxy and α-chloro trifluoromethyl derivatives

S-1-Acyloxy-2,2,2-trifluoroethyl and S-1-chloro-2,2,2-trifluoroethyl dithiocarbonates add efficiently to various functionalised olefins to give the corresponding adducts via a radical chain reaction initiated by a small amount of lauroyl peroxide.     

DFT studies of the structure and vibrational assignments of 4-hydroxy quinazoline and 2-hydroxy benzimidazole

The solid phase FT-IR and FT-Raman spectra of 4-hydroxy quinazoline and 2-hydroxy benzimidazole have been recorded in the regions 4000-400 and 3500-100 cm-1, respectively. Theoretical information on the optimised geometry, harmonic vibrational frequencies, infrared and Raman intensities were obtained by means of density functional theory using standard B3LYP/6-31G* level. This information was used in the assignment of the various fundamentals. Comparison of the simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes.     

A microwave improvement in the synthesis of the quinazoline scaffold

A rapid and efficient microwave-assisted protocol is described that greatly improves a recent synthetic method developed for quinazoline synthesis. The synthetic protocol is based on the use of cycles of microwave irradiation. The optimization process is reported and the experimental results are compared with those of the conventional synthetic route.     

Study on the reactions of 4-amino-5-nitro-6-phenylethynylpyrimidines with amines and thiols

Reactions of 4-amino-5-nitro-6-phenylethynylpyrimidines with amines and thiols have been investigated. Pyridine catalyzes rearrangement of the title compounds into 6-phenyl-7-oxo-7H-pyrrolo[3,2-d]pyrimidine-5-oxides. Primary and secondary amines and thiols take part in a regio- and stereoselective addition reaction to the triple bond of 5-nitro-6-phenylethynylpyrimidines to form the corresponding syn-addition (in the case of secondary amines) or anti-addition (in the case of primary amines or thiols) products.     

A new DMAP-catalyzed and microwave-assisted approach for introducing heteroarylamino substituents at position-4 of the quinazoline ring

We report herein a new methodology for synthesizing quinazoline derivatives bearing a heteroarylamino moiety at position-4 of the quinazoline ring. As an alternative to the Buchwald–Hartwig cross-coupling reaction, which appears, until now, as the only efficient way to react 4-chloroquinazolines with numerous amino nitrogen-containing heterocycles displaying poor nucleophilicity, we developed a DMAP-catalyzed reaction involving microwave irradiation. Optimization of the reaction conditions led to the use of 30 mol % of DMAP in toluene, using a monomode microwave reactor and sealed vials. Moreover, the S_NAr reaction intermediate salt was isolated and fully characterized. Finally, the procedure was extended to two different 2-substituted-quinazoline series and also to various anilines, demonstrating that this approach was a general efficient way to access to such 4-substituted quinazoline scaffolds of high pharmaceutical interest.     

Electrosynthesis of 4-chloro derivatives of pyrazole and alkylpyrazoles

Electrosynthesis of 4-chloro-substituted derivatives of pyrazole and its alkyl derivatives is carried out via the chlorination of original pyrazoles on a Pt anode in aqueous NaCl solutions under conditions of galvanostatic diaphragm electrolysis. The efficiency of this process is shown to depend on the structure of starting pyrazoles, particularly, the donor-acceptor properties of substituents, the position of the latter in the pyrazole ring, and the concomitant contribution of side reactions. Thus the yield of 4-chlorosubstituted products at the chlorination of pyrazole, 3,5-dimethylpyrazole, 1,5-dimethylpyrazole, and 3-nitropyrazole is 68, 92, 53, and 79%, respectively. By the example of 1,5-dimethylpyrazole, the possibility of electrochemical chlorination to the side chain of pyrazoles was demonstrated.     

Synthesis and X-ray information of substituted gem-difluoroallenyl amines

An O to N substitution in 4,4-difluorobutadiene-2,3-ol-1 has been accomplished in very satisfactory yields, and without compromising the gem-difluoroallenyl integrity, using modified Mitsunobu conditions. Recrystallization of the resulting tosyl-substituted amines furnished the first X-ray crystallographic analysis of difluoroallenes.     

Asymmetric induction in the reactions of azinones with C-nucleophiles

Effect of acylating agents on the course of addition of C-nucleophiles to 1,2,4- and 1,3,5-triazinones, as well as to quinoxalin-2(1H)-one, was studied. A series of new azinone derivatives was obtained. A method for the preparation of diastereomerically pure addition products of indoles to 1,2,4-triazinones and quinoxalin-2(1H)-one in the presence of N-Ts-L-amino acid acyl chlorides was suggested.     

Investigation into selective debenzylation and ring cleavage of quinazoline based heterocycles

The selective cleavage of different benzyl bonds within tetrahydroquinazoline and dihydroquinazolinone derived structures can be achieved by the usage of different reduction and debenzylation conditions thereby providing selective removal of O-benzyl protection groups as well as the cleavage of the ring structure within the quinazoline and quinazolinone systems.     

Addition reactions of 2-polyfluoroalkyl substituted 1,3-thiazolin-4-one derivatives

2-Polyfluoroalkyl-5-methoxycarbonylmethylene-thiazolin-4-ones react as dienophiles on the exo-cyclic ylidene bond to give spiro-derivatives and as 1,3-dienes with olefins to give dihydropyranothiazole derivatives. The endo-cyclic CN bond in these compounds do not enter into the cycloaddition reactions.     

Allyl stannanes as electrophiles or nucleophiles in the palladium-catalyzed reactions with alkynes

The reactivity of the allyl stannanes can be inverted by changing the oxidation state of the catalyst from Pd(II) to Pd(0). Whereas with Pd(II) an anti nucleophilic attack of the allyl stannane on the alkyne takes place, the reaction with Pd(0) proceeds by oxidative addition to form (η³-allyl)palladium complexes leading to a formal syn addition to the alkyne. This mechanistic proposal is supported by DFT calculations.     

4-芳氨基-6,7-二甲氧基喹唑啉的合成及生物活性研究

以4-氯-6,7-二甲氧基喹唑啉和4-(2-芳基)乙烯基苯胺或4-[2-(2-呋喃基)]乙烯基苯胺为原料合成了5种4-芳氨基-6,7-二甲氧基喹唑啉类化合物.利用IR、NMR和元素分析等表征手段对其进行了结构确认.这5种化合物对HT-29和MDA-MB-231两种细胞模型的体外抗癌活性测试结果表明,部分化合物具有良好的...     

Spectroscopic and structural aspects of the reactions of 1,4-quinones with sulfur and nitrogen nucleophiles

A series of 1,4-benzoquinone derivatives from 2,5-dichloro-3,6-diethoxy-1,4-benzoquinone and 2,6-dichloro-3,5-diethoxy-1,4-benzoquinone were prepared by nucleophilic substitution reactions of sulfur and nitrogen nucleophiles. Spectral techniques (¹H NMR, ¹³C NMR, FT–IR, and LC–MS) were employed to structurally characterize the reaction products of alkoxy, chloro substituted-1,4-benzoquinones with thiols and amines in the presence of sodium carbonate in ethanol at room temperature. The orientations and the regioselectivity of the reactions of alkoxy, chloro substituted-1,4-benzoquinones with various thiol and amine nucleophiles are discussed.     

Conversion of 2-acetamido-1-thiochromone to the corresponding 4-chloro and 4-amino derivatives

2-Acetimido-4-chloro-2H-1-thiochromene, in which the chlorine atom is exchanged by hydroxy and amino groups, was synthesized by the action of phosphorus oxychloride on 2-acetamido-1-thiochromone. It was established on the basis of the IR, UV, PMR, and mass spectra that the product of the reaction of this compound with aniline has the 2-acetaraido-1-thiochromene structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 622–625, May, 1978.     

Synthesis and activities of new 4-hydroxy benzoxazolone derivatives

<正>A series of new 4-substituted benzoxazolone derivatives were synthesized according to a convenient method,their anti-inflammatory and analgesic activities in vivo were evaluated.All of them were new compounds,the structures of all the synthesized compounds were confirmed by ~1H NMR,~(13)C NMR,ESI-MS and HR-MS.Most of the compounds exhibited anti-inflammatory activity.     

Studies on the reactivity of phenyliodonium ylide of 2-hydroxy-1,4-naphthoquinone: reactions with indole derivatives and other C-nucleophiles

[reaction: see text] Thermal decomposition of phenyliodonium ylide of 2-hydroxy-1,4-naphthoquinone (lawsone) in the presence of indole derivatives affords 3-acylated indoles existing in their enol forms, through a ring contraction and alpha,alpha'-dioxoketene formation reaction. The same reactants afford 3-(3-indolyl)-2-hydroxy-1,4-naphthoquinones in a copper-catalyzed reaction. Enamines, among other C-nucleophiles tested, give analogous results.     

Ring opening of 2-(bromomethyl)-1-sulfonylaziridines towards 1,3-heteroatom substituted 2-aminopropane derivatives

1,3-Heteroatom substituted 2-aminopropane derivatives have been prepared from 2-(bromomethyl)-1-sulfonylaziridines for the first time using sodium azide or different potassium phenoxides in water in the presence of silica gel. The applicability of 1-arenesulfonyl-2-(bromomethyl)aziridines for the synthesis of functionalized sulfonamides has also been demonstrated towards different 1,3-dialkoxy-2-(tosylamino)propanes and 1,3-dialkylthio-2-(tosylamino)propanes upon treatment with the appropriate sodium alkoxide or sodium alkylthiolate in the corresponding alcohol or in methanol, respectively.     

Stable deep blue organic light emitting diodes with CIE of y < 0.10 based on quinazoline and carbazole units

Achieving stable deep blue organic light emitting diodes (OLEDs) with narrow full width at half maximum (FWHM) and color gamut in the range of the commission International de L’Eclairage (CIE) of y ≤ 0.10 is still challenging in display and lighting applications. In this investigation, three donor-acceptor (D-A) deep-blue emitters were designed and synthesized via integrating asymmetric quinazoline (PQ) acceptor with weak donating carbazole (Cz) donor. The effect of the position and number of Cz group in PQ unit are investigated, which is also first examples for systematic research about the effect of different position of asymmetric PQ as acceptor on deep OLEDs. Their bandgaps of 3.12∼3.19 eV and the singlet state energy levels of 3.12∼3.19 eV were found to be sufficiently large to achieve deep blue light. As expected, these emitters-based OLEDs exhibit deep blue emission with the maximum wavelength ≤ 450 nm and narrow FWHM ≈ 60 nm. Especially, a CIE of y = 0.080 was achieved for 4PQ-Cz-based OLED. Significantly, the deep blue electroluminescence (EL) spectra of these three emitters-based OLEDs are very stable and the corresponding CIE coordinates deviation (ΔCIE (x, y)) can be negligible under the applied voltage ranging from 5 V to 9 V.