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1.
William V. Murray Susan K. Hadden Michael P. Wachter 《Journal of heterocyclic chemistry》1990,27(7):1933-1940
New procedures for the synthesis of 3-(1,5-diphenyl-3-pyrazolyl)aryl propanoates and related 2-(1,5-diphenyl-3-pyrazolyl)aryl propanoates from a common 3-hydroxymethylpyrazole intermediate are described. These new procedures include an improved method for carrying out pyridinium chlorochromate oxidations under ultrasonic conditions. These syntheses also utilize lithium triethylphosphonoacetate formed from n-butyllithium and triethylphosphonoacetate as a Wittig-Horner reagent to improve olefination yields. 相似文献
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Ricardo Bossio Stefano Marcaccini Valerio Parrini Roberto Pepino 《Journal of heterocyclic chemistry》1985,22(4):1147-1148
2-(Benzimidazol-2-ylamino)pyridine (4a) , 2-(benzimidazol-2-ylamino)pyrazine (4b) , and 2-(benzimidazol-2-ylamino)thiazole (4c) underwent a ring-closure reaction on treatment with phosgene affording 6H-pyrimido-[1′,2′:5,4][1,3,5]triazino[1,2-a]benzimidazol-6-one (1a) , 6H-pyrazino[1′,2′:5,4][1,3,5]triazino[1,2-a]benzimidazol-6-one (1b) , and 5H-thiazolo[2′,3′:4,5][1,3,5]triazino[1,2-a]benzimidazol-5-one (1c) respectively. The structure of these hitherto unknown heterocyclic systems was confirmed by their ir and mass spectra. 相似文献
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The condensation of 1,2-dialkyl-3-pyrazoIidinones (1) with a series of aldehydes, ketones and esters in the presence of sodium hydride is described. Alkylation of I with several alkyl bromides gave 4-alkyl substitution products in modest yield and reaction of 1,2,4-trimethyl-3-pyrazolidinone with n-butyl bromide gave a 4,4-dialkylation product. Compound 1 reacted with aryl Grignard reagents to form 3-aryl-3-pyrazoIines whereas the corresponding products were not realized in the case of alkyl Grignards. The reduction of a single example of 1 as well as the reduction of two 3-pyrazolines to pyrazolidines is also reported. 相似文献
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2,3-Dichloroquinoxaline and some of its derivatives have been reacted with malononitrile and ethyl cyanoacetate to yield a variety of 3-chloro-2-(cyanomethylene)- 1,2-dihydroquinoxaline derivatives. The reaction of 3-chloro-2-(dicyanomethylene)-1,2- dihydroquinoxaline (2e) with pyridine and its methyl derivatives led to the zwitterionic structures 6a-6c. The structures of the newly synthesized compounds were assigned by spectroscopic data and elemental analyses. 相似文献
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P. V. Pasternak A. S. Golubev A. S. Peregudov N. D. Chkanikov 《Russian Chemical Bulletin》2000,49(7):1255-1256
Reactions of ethyl 3-(diethoxyphosphoryl)-3,3-difluoro-2-oxopropionate with a number of nucleophilic reagents were studied.
New procedures were developed for the synthesis of difluoromethylphosphonate-substituted nitrogen heterocycles. The ketoester
under study is much less reactive in C-hydroxyalkylation of aromatic amines than methyl 3,3,3-trifluoropyruvate.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1258–1260, July, 2000. 相似文献
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A microwave-assisted, telescoped synthesis, involving a Michael-type addition followed by intramolecular cyclization, provides an effective entry to the polysubstituted 3-bromo-2(1H)-pyridinone core. 相似文献
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The reaction of ethyl 3-(o-trifluoroacetamidophenyl)-1-propargyl carbonates with formate anions in the presence of Pd(PPh3)4 affords 2-alkylindoles in good to excellent yields. 相似文献
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N. N. Polygalova A. G. Mikhailovskii V. V. Udodov A. I. Mikhalev M. I. Vakhrin 《Chemistry of Heterocyclic Compounds》2007,43(8):1024-1028
It has been shown that the reaction of dialkylbenzylcarbinols with 3-cyano-2-pyridones and 2-chloro-3-cyanopyridines gives
the corresponding 3,3-dialkyl-1-(3-pyridyl)-3,4-dihydroisoquinolines.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1208–1212, August, 2007. 相似文献
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A number of 4-n-nonylphenyl esters and mono- and di-fluorinated 4-n-nonylphenyl esters derived from 3-(4'-n-alkoxybiphenylyl)propanoic acids (II) have been synthesized and their thermotropic liquid crystal properties assessed with a view to obtaining tilted smectic phases for possible use in ferroelectric display devices. Many of these compounds exhibit wide temperature range SC and SI/F phases, but none gave the ideal phase sequence SC-SA-N-I mainly because the structure of these compounds was not conducive to the formation of the nematic phase. To try to alleviate this problem a series of 4-n-nonylphenyl esters based on 3-(4'-n-alkoxybiphenylyl)-3-methylpropanoic acid was prepared, where a lateral methyl group was incorporated in the β-position of the -CH2CH2CO2- linkage. Incorporation of the lateral methyl group encouraged the formation of a nematic phase at the expense of both the smectic A phase and tilted smectic phases. 相似文献
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A single step synthesis of 2,3-dialkyl-6-nitro-quinazolin-4(3H)-imines and 3,5-dialkyl-9-nitro-imidazo-[1,2-c]-quinazolin-2(3H)-ones from simple carbonyl compounds, primary amines or amino acid methyl esters and 2-azido-5-nitro-benzonitrile was developed. Key intermediates were N,N′-disubstituted amidines obtained by rearrangement of 4,5-dihydrotriazoles; the new heterocyclic rings were formed by spontaneous intramolecular reaction of the amino and cyano groups which are present in the intermediates. 相似文献
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[reaction: see text] The palladium-catalyzed reaction of ethyl 3-(o-trifluoroacetamidophenyl)-1-propargyl carbonate with piperazines in the presence of Pd(PPh(3))(4) in THF at 80 degrees C affords 2-(piperazin-1-ylmethyl)indoles in excellent yields. Good to excellent yields are also obtained with other secondary amines. 相似文献
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Goryaeva M. V. Kushch S. O. Burgart Ya. V. Saloutin V. I. 《Russian Chemical Bulletin》2020,69(11):2163-2166
The peculiarities of the three-component cyclization of ethyl 4,4,4-trifluoroacetoacetate and 1,2-ethanediamines with 3-methylbutan-2-one into hexahydroimidazo[1,2-a]pyridin-5-ones were studied. The reactions proceeded under mild conditions. The use of methyl ketone with a bulky isopropyl substituent increased the stereoselectivity of the transformations, but the reaction with 1,2-diaminopropane was accompanied by the formation 4-[(1-ammoniopropan-2-yl)amino]-1,1,1-trifluoro-4-oxobut-2-en-2-olate as a by-product.
相似文献17.
Xu Qin Li Yun Xu Yang Wei Li Wang Bin Hu Hui Min Xue Tian Yi Zhang Xue Tao Zhang 《中国化学快报》2011,22(7):765-767
A practical chemical synthesis of L-carmtine(1) has been accomplished from(R)-3-chloro-1,2-propanediol((R)-4),which is a main by-product originated from(R,R)-Salen Co(Ⅲ) catalyzed hydrolytic kinetic resolution(HKR) of(±)-epichlorohydrin.(R)-4 was utilized as a chiral starting material to prepare the key intermediate cyclic sulfite((R)-S).The new synthetic approach demonstrated an efficient utilization of organic by-product for the asymmetric synthesis of bioactive compounds. 相似文献
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A direct DDQ-mediated dehydrogenative intramolecular cyclization of (Z)-1,2,3-triaryl substituted propylenes promoted by Cu(OAc)2 was developed, providing 1,2-diarylindene derivatives in moderate to good yields (up to 92%) under mild conditions. This protocol provides a straightforward access to 1,2-diarylindenes via DDQ-mediated benzylic/allylic sp3 C–H bond activation. 相似文献
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The oxidative cyclization/dimerization reaction between two classes of allenes with different functionalities was reported to provide an efficient route to polysubstituted 4-(3'-furanyl)-2(5H)-furanones, which are not readily available from the known methods. The highly optically active butenolides could be easily formed from the optically active 2,3-allenoic acids, which was obtained conveniently through chiral resolution with optically active amines, that is, cinchonidine or alpha-methyl benzylamine. A mechanistic study showed that the reaction proceeded via a matched double oxypalladation-reductive elimination process. The Pd(II) species may be regenerated via the subsequent cyclometallation of two equivalents of 1,2-allenyl ketones with Pd(0) and protonlysis of Pd enolates formed with the in situ generated HCl. 相似文献