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1.
Sixteen novel 2-substituted-5,8,9-trimethyl-3-(4-fluoro-substituted)phenyl-thieno[3′,2′-5,6] pyrido[4,3-d]pyrimidin-4(3H)-ones 5a-5p were designed and have been successfully synthesized via tandem aza-Wittig and annulation reactions of the corresponding iminophosphorances 1, para-fluoro phenyl isocyanate, and substituted phenols or amines in 73-90% isolated yields. Their structures were clearly verified by IR, 1H NMR, EI-MS spectroscopy and elemental analysis, and in the case of compound 5a, analyzed by single-crystal X-ray diffraction further. The results of preliminary bioassay indicated that some compounds possess inhibition activities against Rhizoctonia solani and Botrytis cinereapers at a dosage of 50 mg/L. 相似文献
2.
Biswajita Baruah 《Tetrahedron letters》2009,50(2):243-245
5-Formyl-6-tertiaryamino uracils 3 prepared from 6-chloro-5-formyl uracil derivative 1 react with barbituric acids 4 in the presence of base catalyst to afford a novel class of spirosubstituted pyrido[2,3-d]pyrimidines 5 via 1,6-electro-cyclisation in excellent yields. 相似文献
3.
A new, high yield multicomponent reaction providing multifunctionalized pyrido[2,3-d]pyrimidines in a microwave-assisted one-pot cyclocondensation of α,β-unsaturated esters, amidine systems and malononitrile (or ethyl cyanoacetate) is described (the ‘Victory’ reaction). 相似文献
4.
Pyrido[2,3-d]pyrimidines are synthesized in a two-step procedure from amides and tetrazolo[1,5-a]pyridine-8-carbonyl chloride. Reaction of the crude imides with triphenylphosphine effects an intramolecular aza-Wittig reaction to afford a variety of substituted pyrido[2,3-d]pyrimidines in good to moderate yields (30-76%). 相似文献
5.
Vegar Stockmann 《Tetrahedron》2008,64(32):7626-7632
Two new types of pyrido-fused tris-heterocycles (1a,b and 2a,b) have been prepared from 3-aminopyridine in five/six steps. A synthetic strategy for the preparation of the novel pyrido[3,4-b]thieno[2,3- and 3,2-d]pyrroles (1a,b) and pyrido[4,3-e]thieno[2,3- and 3,2-c]pyridazines (2a,b) has been studied. The Suzuki cross coupling of the appropriate 2- and 3-thienoboronic acids (3,4) and 4-bromo-3-pyridylpivaloylamide (9) afforded the biaryl coupling products (10,11) in high yields (85%). Diazotization of the hydrolysed (2-thienyl)-coupling product (12) and azide substitution gave the 3-azido-4-(2-thienyl)pyridine intermediate (72%, 14). 3-Azido-4-(3-thienyl)pyridine (15) was prepared by exchanging the previous order of reactions. The desired β-carboline thiophene analogues (1a,b) were obtained via the nitrene by thermal decomposition of the azido precursors (14,15). By optimising conditions for intramolecular diazocoupling, the corresponding pyridazine products (72-83%, 2a,b) were afforded. 相似文献
6.
Vegar Stockmann 《Tetrahedron》2008,64(49):11180-11184
Three novel pyrido-fused tris-heterocycles have been prepared based on a Suzuki coupling and subsequent cyclisation approach. Pyrido[4,3-e]pyrrolo[2,3-c]pyridazine (3b, 77%) and pyrido[4,3-e]furano[2,3-c]pyridazine (5b, 76%) were obtained by intramolecular diazocoupling. Successful diazocoupling of furan (5b) is thus reported for the first time by NOBF4 generation of the diazonium intermediate. N-TIPS-pyrido[3,4-b]pyrrolo[3,2-d]pyrrole (TIPS-4b) was synthesised by thermal cyclisation of pyridyl nitrene in considerably higher yield (71%) than previously experienced from similar cyclisations, due to TIPS-activation. 相似文献
7.
The synthesis of a 5,7-dichloropyrido[4,3-d]pyrimidine scaffold is described. The chlorine at position 5 can selectively be displaced by different palladium-catalyzed cross-coupling reactions and nucleophilic aromatic substitutions. In the subsequent step, the chlorine at position 7 can be further derivatized. The described synthetic sequence allows for the construction of a diverse pyrido[4,3-d]pyrimidine library with structural variations at positions 5 and 7. 相似文献
8.
Minoo Dabiri 《Tetrahedron》2007,63(8):1770-1774
An efficient and direct procedure for the synthesis of pyrimido[4,5-d]pyrimidine-2,4,7-trione derivatives has been described under microwave-assisted conditions. Reaction of 6-amino-1,3-dimethyluracil with aromatic aldehydes resulted in the formation of pyrido[2,3-d:6,5-d] dipyrimidine-2,4,6,8-tetrone derivatives. 相似文献
9.
Ying Liang 《Journal of fluorine chemistry》2007,128(7):879-884
Eighteen novel 5-alkylamino-6-aryl-3-phenyl-2-thioxo-2,3-dihydrothiazolo[4,5-d]pyrimidin-7(6H)-ones 5a-r were designed and easily synthesized via a tandem aza-Wittig reaction. Treatment of iminophosphorane 2 with aromatic isocyanate gave carbodiimide 3, which reacted with fluoro-substituted alkylamines to provide the title compounds in 65-87% isolated yields using sodium ethoxide as catalyst. All compounds 5 were confirmed by IR, 1H NMR, MS and elemental analysis, and compound 5p was further analyzed by single-crystal X-ray diffraction. The preliminary bioassay indicated that some compounds showed significant inhibition activities against the root growth of rape and barnyard grass at a dosage of 100 mg/L. 相似文献
10.
Ipsita Devi 《Tetrahedron letters》2004,45(11):2405-2408
N,N-Dimethyl-5-formylbarbituric acid 1 reacts with maleimide 2 and phenyl isocyanate/phenyl isothiocyanate 4 under microwave-assisted conditions in the solid phase to afford pyrano[2,3-d]pyrimidines 3 and oxazino[4,5-d]pyrimidines 5 in excellent yields. Under identical conditions, N,N-dimethyl-6-amino-5-formyluracil 6 reacts with 2 and 4 to give pyrido[2,3-d]pyrimidine derivative 7 and pyrimido[4,5-d]pyrimidines 8 in high yields. 相似文献
11.
Inga Cikotiene Rita Buksnaitiene Simonas Rudys Marius Morkunas Dainius Motiejaitis 《Tetrahedron》2010,66(1):251-345
An efficient and versatile tandem processes of acetalisation and cycloisomerization reactions have been developed for the reactions of 6-phenylethynylpyrimidine-5-carbaldehydes. The influence of the catalyst and role of the substituent in the position 4 of the pyrimidine ring have been studied. Regioselective synthesis of 5,7-dihydrofuro[3,4-d]pyrimidine and pyrano[4,3-d]pyrimidine cores is described. 相似文献
12.
Thomas Brady 《Tetrahedron letters》2009,50(46):6223-6227
Novel 2,3-substituted-2,4-dihydro-pyrazolo[4,3-d]pyrimidine-5,7-diones were successfully synthesized with moderate to good yields using a new synthetic approach. The structures of the regio-isomers in this series were determined by single crystal X-ray analysis and NMR spectra. 相似文献
13.
Zhende Liu 《Tetrahedron》2007,63(9):1931-1936
A flexible method for the synthesis of 5,6-disubstituted furo[2,3-d]pyrimidine derivatives is described. The key step is a palladium-catalyzed arylative cyclization of alkynylpyrimidinols with various aryl iodides, which gave the title compounds in 36-75% yield. 相似文献
14.
A novel solid-phase method for the synthesis of 4-methyl-pyrido[2,3-d]pyrimidin-7-one compounds with two diversity points is described. The polymer supported methylsulfonyl derivatives A3, achieved by coupling compound G with different resin-bound amines A1 followed by oxidation with MCPBA, are substituted with several amines R1R2NH. Final cleavage affords 126 compounds having formula H in good yield and purity. 相似文献
15.
Anu Agarwal 《Tetrahedron letters》2005,46(8):1345-1348
We have synthesized a library of 16 dihydropyrido[2,3-d]pyrimidines in high yields (82-92%) on solid support using microwave irradiation. 相似文献
16.
The reaction of isoxazolo[3,4-d]pyrimidine 1 and cyanoolefins 2 in the presence of triethylamine (Et3N) as a catalyst afforded an unprecedented one-pot synthesis of biologically important pyrido[2,3-d]pyrimidine oxides 3 in excellent yields. 相似文献
17.
The 6-(4-alkoxycarbonylalkoxy)phenoxy-3-alkylthio-5-(fluoro-substituted)phenyl-1-phenylpyrazolo[3,4-d]pyrimidin-4-ones 6 have been successfully synthesized via a tandem aza-Wittig and annulation reactions of the corresponding iminophosphorances 4, aromatic isocyanate, and substituted phenols 2 in 59-69% isolated yields using actonitrile as solvent. These novel compounds 6 could be oxidized to sulfones 7 by hydrogen peroxide in satisfactory yields (57-93%). Their structures were clearly verified by spectroscopic data (IR, 1H NMR, 13C NMR, MS, Elemental analysis or X-ray diffraction crystallography). The results of preliminary bioassay indicated that these compounds possess herbicidal activity against the root of rape and barnyard grass. 相似文献
18.
Exploiting the diene nature of 6-[1-aza-2-(dimethylamino)prop-l-enyl]-1,3-dimethyluracil (2), novel 5-aryl-pyrido[2,3-d]pyrimidines (5a–h) have been synthesized. The reaction proceeds through a triene intermediate whose structure has been conclusively established by single crystal X-ray analysis. Role of water is intriguing as the reaction can be stopped at the intermediate stage. Synthesized compounds have been screened for possible antibacterial properties and results showed modest activity. 相似文献
19.
Yu-Ying HuangLi-Ya Wang Chun-Hsi ChangYueh-Hsiung Kuo Kimiyoshi KanekoHiroyuki Takayama Masayuki KimuraShin-Hun Juang Fung Fuh Wong 《Tetrahedron》2012,68(47):9658-9664
An efficient one-pot methodology for the synthesis of pyrazolo[3,4-d]pyrimidines was developed by using 5-aminopyrazoles with formamide in presence of PBr3 as the coupling agent. Among the examples presented in this work, compounds 41 and 54-56 with phenyl or 2-quinolinyl groups at N-1 and p-Me-Ph, p-Cl-Ph, or p-OMe-Ph group at C-3 position in the pyrazole ring possessed better potency against NCI-H226 and NPC-TW01 cancer cells with GI50 values between 18 μM and 39 μM. 相似文献
20.
Yvonnick LoidreauPascal Marchand Carole Dubouilh-BenardMarie-Renée Nourrisson Muriel DuflosThierry Besson 《Tetrahedron letters》2012,53(8):944-947
This Letter describes for the first time the synthesis of pyrido[2′,3′:4,5]furo[3,2-d]pyrimidines substituted by a primary or secondary amino group on position 4 of the pyrimidine ring. Application of microwave irradiation technology allowed fast and convenient procedures. 相似文献