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1.
Antimony trichloride efficiently catalyses diastereoselective three-component reaction of urea, aromatic aldehydes and 2,3-dihydrofuran or 3,4-dihydro-2H-pyran leading to 4-arylhexahydrofuro[2,3-d]pyrimidin-2(3H)-ones and 4-arylhexahydro-1H-pyrano[2,3-d]pyrimidin-2(8aH)-ones, respectively in good yield. 相似文献
2.
The reaction of 6-amino-1,3-dimethyluracil with equimolar amounts of arylalkanone Mannich bases under optimized reaction conditions leads to 7-aryl-5,6-dihydropyrido[2,3-d]pyrimidines in a yield of 50-80%. Functionalization of these dihydropyridopyrimidine(1H,3H)-2,4-diones with the Vilsmeier reagent affords, depending on the reaction conditions, either 6-dimethylaminomethylidene substituted 5H-pyrido[2,3-d]pyrimidine(1H,3H)-2,4-diones or the corresponding pyridopyrimidine(1H,3H)-2,4-diones bearing a carboxaldehyde function in position 6 of the heterocycle. Some further transformations of the aldehyde function demonstrate the synthetic potential of the synthesized structures, introducing pharmacologically relevant basic substituents into the side chain of these pyrido[2,3-d]pyrimidine derivatives. 相似文献
3.
Khosrow Jadidi 《Tetrahedron》2009,65(10):2005-43
A simple and efficient cyclocondensation reaction of 2,6-diaminopyrimidin-4(3H)-one and isatins for the synthesis of spiro[pyrimido[4,5-b]quinoline-5,5′-pyrrolo[2,3-d]pyrimidine] and spiro[indoline-pyrido[2,3-d:6,5-d′]dipyrimidine] derivatives is reported. 相似文献
4.
Tatsuki Koike Yasutaka HoashiTakafumi Takai Osamu Uchikawa 《Tetrahedron letters》2011,52(23):3009-3011
The 4-aza analog of ramelteon (−)-1, a novel tricyclic 1,6,7,8-tetrahydro-2H-cyclopenta[d]furo[2,3-b]pyridine derivative, was synthesized via the intramolecular inverse electron demand Diels-Alder reaction followed by fluoride-induced desilylation-cyclization. 相似文献
5.
Nazariy T. Pokhodylo 《Tetrahedron》2008,64(7):1430-1434
4,5-Disubstituted and 4-substituted alkyl 2-amino-thiophene-3-carboxylates react with triethyl orthoformate and sodium azide in acetic acid to yield new 2-(1H-tetrazol-1-yl)-4-R1-5-R2-thiophene derivates. It was established that the reaction of these tetrazoles with hydrazine generates the insufficiently studied 2,3-diaminothieno[2,3-d]pyrimidin-4(3H)-one system. It is significant that the reaction mentioned above is the unique tetrazole ring cleavage under the action of hydrazine. 相似文献
6.
Tatjana Gazivoda Kraljevi? Andrea Bistrovi?Matea Dedi? Sandra Kraljevi? Paveli?Mirela Sedi? Silvana Rai?-Mali? 《Tetrahedron letters》2012,53(38):5144-5147
A series of the novel 5-alkynyl- and furo[2,3-d]pyrimidine derivatives in which the sugar moiety is replaced by a methoxymethyl (MOM) group is synthesised using the Sonogashira cross-coupling reaction under both conventional and microwave conditions, in good to excellent yields. The 5-endo-dig cyclisation of 5-alkynylpyrimidine derivatives promoted by a Pd-catalyst or base gives the corresponding furo[2,3-d]pyrimidines in good yields. 相似文献
7.
Philippe Franck Beáta Dajka-Halász Katrien Monsieurs Bert U.W. Maes 《Tetrahedron》2008,64(26):6030-6037
Pd-catalyzed cyclodehydrohalogenation involving oxidative addition of aromatic C-Br or activated azaheteroaromatic C-Cl bonds and C(sp2)-H activation have been investigated at high reaction temperatures (180-200 °C). This allowed the fast (10-30 min) synthesis of a variety of azaheteroaromatic ring systems (dibenzo[f,h]phthalazine, dibenzo[f,h]cinnoline, benzofuro[2,3-d]pyridazine, 5H-pyridazino[4,5-b]indole, 7H-indolo[2,3-c]quinoline and 5H-δ-carboline) in moderate to good yields. 相似文献
8.
Libraries of skeletally diverse potential bioactive polycyclic/spirocyclic heterocyclic compounds; 2-amino-7,9-dimethyl-5-oxo-4-aryl-4,5,6,7-tetrahydropyrano[2,3-d]pyrazolo[3,4-b]pyridine-3-carbonitrile, 2′-amino-7′,9′-dimethyl-2,5′-dioxo-6′,7′-dihydro-5′H-spiro[indoline-3,4′-pyrano[2,3-d]pyrazolo[3,4-b]pyridine]-3′-carbonitrile, and 5,5′-(arylmethylene)bis(4-hydroxy-1,3-dimethyl-1H-pyrazolo[3,4-b]pyridin-6(7H)-one) have been synthesized through a multi-component reaction using novel heterocyclic active methylene compound 4-hydroxy-1,3-dimethyl-1H-pyrazolo[3,4-b]pyridine-6(7H)-one as one of the building blocks. This protocol can be considered to be an efficient and eco-friendly strategy for diversity oriented synthesis. 相似文献
9.
Timur O. Zanakhov Ekaterina E. Galenko Mariya A. Kryukova Mikhail S. Novikov Alexander A. Khlebnikov 《Molecules (Basel, Switzerland)》2021,26(7)
An atom economical method for the preparation of variously substituted 4H-pyrrolo[2,3-d]oxazoles was developed on the basis of thermal isomerization of 5-(2H-azirin-2-yl)oxazoles. The latter were prepared by Rh2(oct)4 catalyzed reaction of 2-(3-aryl/heteroaryl)-2-diazoacetyl-2H-azirines with a set of substituted acetonitriles, benzonitriles, acrylonitrile and fumaronitrile. According to DFT calculations the transformation of 5-(2H-azirin-2-yl)oxazole to 4H-pyrrolo[2,3-d]oxazole occurs through the nitrenoid-like transition state to give a 3aH-pyrrolo[2,3-d]oxazole intermediate, followed by 1,5-H-shift. 相似文献
10.
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
11.
Mohammad Reza Mohammadizadeh Mojtaba Bahramzadeh S. Zainabkhatoon Taghavi 《Tetrahedron letters》2010,51(44):5807-5809
A novel and practical one-pot procedure is described for the preparation of several new of 3H-spiro[isobenzofuran-1,6′-pyrrolo[2,3-d]pyrimidine]-2′,3,4′,5′-tetraones based on the addition reaction of ninhydrin and 6-aminouracils followed by oxidative cleavage of their corresponding dihydroxyindenopyrrolopyrimidines. 相似文献
12.
Gundurao Kolavi 《Tetrahedron letters》2006,47(16):2811-2814
Novel heterocyclic systems 2-alkyl/aryl-9-(2-hydroxybenzylidene)-7,9-dihydro-8H-[1,3,4]thiadiazolo[2′,3′:2,3]imidazo[4,5-d][1,2]diazepin-8-one and 9-(2-hydroxy-benzylidene)-3,3-dimethyl-3,4,7,9-tetrahydro-2H-11-thia-4b,6,7,10-tetraazaindeno[1,2-a]azulene-1,8-dione are synthesized via an intramolecular amidation reaction. An interesting ring opening and cyclization of 2-alkyl/aryl-6-(2-oxo-2H-chromen-3-yl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde and 6,6-dimethyl-8-oxo-2-(2-oxo-2H-chromen-3-yl)-5,6,7,8-tetrahydroimidazo[2,1-b][1,3]benzothiazole-3-carbaldehyde are discussed. 相似文献
13.
Michail N. Elinson Anatolii N. Vereshchagin Nikita O. Stepanov Pavel A. Belyakov Gennady I. Nikishin 《Tetrahedron letters》2010,51(50):6598-6601
Cascade assembly of N,N′-dialkylbarbituric acids and aldehydes in the presence of bromine leads to the selective and efficient formation of substituted 1,5-dihydro-2H,2′H-spiro(furo[2,3-d]pyrimidine-6,5′-pyrimidine)-2,2′,4,4′,6′-(1′H,3H,3′H)-pentones in 70-88% yields via a complex cascade process. Spirobarbiturates containing the furo[2,3-d]pyrimidine framework are a class of compounds with interesting pharmacological and physiological activity. 相似文献
14.
AlCl3 facilitated C-C bond forming reaction between 4-chloro-thieno[2,3-d]pyrimidines and (hetero)arenes affording a direct and single-step method for the synthesis of 4-(hetero)aryl substituted thieno[2,3-d]pyrimidines. A number of novel thienopyrimidines were prepared in good to excellent yields using this methodology. The molecular structure of a representative compound was established unambiguously by single crystal X-ray diffraction. 相似文献
15.
Chromones bearing electron-withdrawing substituents at the 2- or 3-position react with nonstabilized azomethine ylides to produce 1-benzopyrano[2,3-c]pyrrolidines in good yields. Reactions of 3-cyanochromones proceed diastereoselectively to give 1-benzopyrano[2,3-c]pyrrolidines and tetrahydro-1H-spiro[chromeno[2,3-c]pyrrol-9,5′-oxazolidine]-9a-carbonitriles, depending on the reactant ratio, as a result of a 1,3-dipolar cycloaddition of the azomethine ylide at the double bond and carbonyl group of the chromone system. The latter undergoes demethylenation and recyclization into a novel hexahydrochromeno[2,3-c:3,4-c′]dipyrrole tetracyclic system on heating with hydrochloric acid. 相似文献
16.
P. Lakshmi Reddy D. Ashok Kumar M. Lakshmi Devi T. Veera Reddy B.V. Subba Reddy R. Narender 《Tetrahedron letters》2014
A three-component, four center Ugi reaction of 3-(1-(2-aminophenyl)-5-phenyl-1H-pyrrol-2-yl)propanoic acid with aromatic aldehyde and t-butyl isocyanide has been achieved to produce a novel class of N-tert-butyl-2-(6-oxo-11-phenyl-7,8-dihydrobenzo[b]pyrrolo[1,2-d][1,4]diazacine-5(6H)-yl)-2-phenylacetamides in moderate to good yields. 相似文献
17.
Leila Moafi 《Tetrahedron letters》2010,51(48):6270-6274
The synthesis of 2-amino-4-cyano-4H-chromene derivatives as new HA 14-1 analogues by a simple and efficient method is reported. In addition, the reaction of 2-amino-2H-chromene-3-carbonitriles, salicylaldehydes and amines results in the formation of new chromeno[2,3-d]pyrimidine derivatives. 相似文献
18.
The thermolysis of (3R,9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole-3-carboxylic acids in Ac2O led to novel 3-methylene-2,5-dioxo-3H,9bH-oxazolo[2,3-a]isoindoles and chiral (9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindoles were obtained on FVP. Starting from l-cysteine methyl ester (3R,10bR)-5-oxo-2,3-dihydro-10bH-[1.3]thiazolo[3,2-c][1,3]benzoxazines were obtained as single stereoisomers. The thermolysis of (3R,10bR)-5-oxo-2,3-dihydro-10bH-[1.3]thiazolo[3,2-c][1,3]benzoxazine-3-carboxylic acid in Ac2O gave 5-acetyl-2-phenyl-2,3-dihydrothiazole. The structures of methyl (3R,9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole-3-carboxylate 1a and methyl (2R,4R)-N-chlorocarbonyl-2-(2-hydroxyphenyl)thiazolidine-4-carboxylate 9 were determined by X-ray crystallography. 相似文献
19.
Some new 7,9-disubstituted 7H-1,2,3,4-tetrazolo[1,5-c]pyrrolo[3,2-e]pyrimidines 5 have been synthesized either by diazotization of 4-hydrazino-5,7-disubstituted-7H-pyrrolo[2,3-d]pyrimidines 4 obtained by hydrazinolysis of 4-chloro-5,7-disubstituted-7H-pyrrolo[2,3-d]pyrimidines 3 or via a substitution reaction between 3 and sodium azide. 5,7-Disubstituted-7H-pyrrolo[2,3-d]pyrimidin-4(3H)-ones 2 were obtained by cyclocondensation of 2-amino-3-cyano-1,4-disubstituted pyrroles 1 with formic acid which on chlorination using phosphorus oxychloride afforded 3 . A novel route for the synthesis of 4-amino-5,7-disubstituted-7H-pyrrolo[2,3-d]pyrimidines 6 by the reductive ring cleavage of 5 has been reported. 相似文献
20.
Reaction of 3-formylchromones with 2-aryl-4-hydroxy-6H-1,3-thiazin-6-ones in the presence of pyridine leads to formation of a mixture of novel N-thioaroyl-5-hydroxy-2H,5H-pyrano[3,2-с]chromen-2-one-3-carboxamides and 2-aryl-5-(4′-oxochromen-3′-yl)-6,7-dihydro-4H,5H-pyrano[2,3-d][1,3]thiazine-4,7-diones. The yields of these compounds clearly depend on the nature of the substituent on the 3-formylchromone and on the reaction conditions. 相似文献