- Synthesis of dihydrobenzo[b]pyrimido[4,5-e][1,4]thiazepines; derivatives of a novel ring system
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Several derivatives of the novel dihydrobenzo[b]pyrimido[4,5-e][1,4]thiazepine ring system have been synthesised through the initial heterocyclisation of 2,4-dichloro-5-(chloromethyl)-6-methylpyrimidine with o-aminothiophenol followed by treatment with various secondary amines in boiling ethanol.
- Akbarzadeh, Marzieh,Bakavoli, Mehdi,Eshghi, Hossein,Shiri, Ali,Tajabadi, Javad
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- Synthesis of novel derivatives of (benz)imidazo[2,1-b]pyrimido[4,5-d][1,3] thiazine
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Several derivatives of the novel heterocyclic systems 2-substituted-imidazo- and benzimidazo-[2,1-b]pyrimido[4,5-d][1,3]thiazine have been synthesised through the one-pot cyclocondensation of 2,4-dichloro-5-(chloromethyl)-6-methylpyrimidine with imidazolidine-2thione and 1H-benzimidazole-2(3H)-thione and subsequently substituted by various secondary amines in moderately good yields.
- Akbarzadeh, Marzieh,Bakavoli, Mehdi,Eshghi, Hossein,Shiri, Ali
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- Synthesis of 2-substituted-4-methyl-5,13-dihydropyrimido[4′,5′:5,6][1,4]thiazepino[2,3-b]quinoxaline as a new heterocyclic system
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2-Substituted-4-methyl-5,13-dihydropyrimido[4′,5′:5,6][1,4]thiazepino[2,3-b]quinoxalines (7a-g), derivatives of a new heterocyclic system were synthesized through cyclocondensation of 2,4-dichloro-5-(chloromethyl)-6-methylpyrimidine (3) with 3-aminoquinoxaline-2-thiol (4) and subsequent substitution by various secondary amines. Regioselective heterocyclization was confirmed by X-ray crystallographic analysis for 4-methyl-2-(pyrrolidin-1-yl)-5,13-dihydropyrimido[4′,5′:5,6] [1,4]thiazepino[2,3-b]quinoxaline (7a).
- Akbarzadeh, Marzieh,Bakavoli, Mehdi,Eshghi, Hossein,Shiri, Ali,Azizollahi, Hamid,Mague, Joel T.
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- Synthesis of l-(alkoxymethyl)-5-benzyl-6-methyluracil as potential nonnucleoside HIV-1 RT inhibitors
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1,3-Dibenzyl-6-methyl-5-zincbromomethyluracil 6 was prepared starting from 6-methyluracil 1. The cross-coupling reaction of benzylic zinc reagent 6 with PhI using bis(dibenzylideneacetone) palladium(0) and (o-furyl)3P as catalyst gave 1,3,5-tribenzyl-6-methyluracil 7. The N-1,N-3-dibenzyl group could be removed in dealkylation to give the 5-benzyl-6-methyluracil 8. It was N-1-alkylated with chloromethyl ethyl ether or chloromethyl benzyl ether to obtained the targets 9a and b. All synthesized compounds were tested for their inhibition of HIV-1 reverse transcriptase, and moderate activity were found for target compounds 9a and b and 5. Copyright Taylor & Francis Group, LLC.
- Chen, Yanli,Guo, Ying,Yang, Hua,Wang, Xiaowei,Liu, Junyi
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- Synthesis of the novel bicyclic oxepinopyrimidine and fluorinated pyrrolidinopyrimidines
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The new 5,6-disubstituted pyrimidine nucleoside analogues (5-8) were synthesized by addition of the C-6 lithiated pyrimidine derivative to oxirane as key reaction step. The bicyclic tetrahydrooxepinopyrimidine (9) and fluorinated pyrrolidinopyrimidines (12 and 15) were obtained by intramolecular linkage of acyclic chain to the CH2-5 and N-1 of the pyrimidine ring. The structure of compound (9) containing pyrimidine and tetrahydrooxepine skeleton was determined unequivocally by its X-Ray crystal structure analysis.
- Batinac, Sanja,Sermek, Draginja Mrvo?,Cetina, Mario,Paveli?, Kre?imir,Mintas, Mladen,Rai?-Mali?, Silvana
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- Regioselective synthesis of new 5-methyl-5H-pyrimido[4′,5′:4,5][1,3]thiazino [3,2-a]perimidines
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A convenient and efficient regioselective synthesis of new pyrimido[4′,5′:4,5] [1,3]thiazino[3,2-a]perimidines is described through intermolecular heterocyclization of 2,4-dichloro-5-(chloromethyl)-6-methylpyrimidine and 1H-perimidine-2(3H)-thione in short reaction times under mild conditions.
- Firoozi, Neda,Bakavoli, Mehdi,Eshghi, Hossein,Ramezanian, Navid
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- The design and synthesis of N-1-alkylated-5-aminoaryalkylsubstituted-6-methyluracils as potential non-nucleoside HIV-1 RT inhibitors
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Novel compounds 1a-u, which can be considered as hybrid analogues of MKC-442 and pyridinon, have been synthesized and evaluated as inhibitors of HIV-1 reverse transcriptase (HIV-1 RT). Starting from 6-methyuracil 2, 1-alkylated-5-bromomethyl-6-methyluracils 8 was prepared in four steps by hydroxylmethylation, etherification, N-1 alkylation, and bromination. Finally, compounds 1a-u were achieved in the displacement of 5-bromomethyl group by nucleophiles with amino compounds. Some of compounds 1a-u showed potent inhibitory activity against HIV-1 RT. The most active compounds showed activity in the low micromolecular range with IC50 values (IC50 0.82-5.09 μM) comparable to that of nevirapine (IC50 10.60 μM). The biological testing results are in accordance with the docking.
- Lu, Xiao,Chen, Yanli,Guo, Ying,Liu, Zhenming,Shi, Yawei,Xu, Yang,Wang, Xiaowei,Zhang, Zhili,Liu, Junyi
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p. 7399 - 7407
(2008/09/17)
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- 4,5-DISUBSTITUTED-2-ARYL PYRIMIDINES
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4,5-disubstituted-2-arylpyrimidines of Formula (I) and Formula (II) are provided: wherein R1, R2, R3, R8, R9, A and Ar are defined herein. Such compounds are ligands of C5a receptors. Preferred compounds of Formula I and II bind to C5a receptors with high affinity and exhibit neutral antagonist or inverse activity at C5a receptors. The present invention also relates to pharmaceutical compositions comprising such compounds, and to the use of such compounds in treating a variety of inflammatory, cardiovascular, and immune system disorders. In addition, the present invention provides labeled 4,5-disubstituted-2-arylpyrimidines, which are useful as probes for the localization of C5a receptors.
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Page/Page column 60
(2008/06/13)
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- Elimination Reactions of α-Substituted Thymines Derived from Tautomeric Heterocyclic Thiols and Selenols
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Tautomeric heterocyclic thiols are readily alkylated by 5-(halomethyl)uracils, giving both S- and N-substituted products.S derivatives such as 19 undergo rapid elimination of thiolate anion in base, whereas the isomeric 6-substituted uracil drivatives such as 3 show no elimination.Kinetic and 13C NMR studies are consistent with an elimination mechanism involving heterocyclic quinone methide intermediate, which can arise from the 5-substituted uracil derivatives but not from the 6-substituted series.The proposed mechanism is further supported by studies of the pH dependency of the elimination reaction and of the effect of substitution in the uracil ring (see Table I and Scheme II).N-Substituted (thione) derivatives such as 36 also undergo base-catalyzed elimination, but a rates some 105 to 106 times slower than those for the corresponding S derivatives when the uracil is unsubstituted on nitrogen.The high sensivity of elimination rate to changes in the leaving group atom is attributed to a transition state in which the connecting methylene group has considerable carbocation character (see Scheme VI).Analogous derivatives (such as 42) of tautomeric heterocyclic selenols have also been prepared, and their elimination kinetics further support this interpretation.
- Bartles-Keith, James R.,Mahoney, J. Barry,Puttick, Anthony J.
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p. 980 - 987
(2007/10/02)
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- Total Synthesis of the Antibiotic Sparsomycin, a Modified Uracil Amino Acid Monoxodithioacetal
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The total syntheses of sparsomycin (1), a naturally occurring antibiotic and antitumor substance, and its three stereomers 65-67 are described for the first time.In a convergent approach, the carboxylic acid 2 and the amine 3 were synthesized followed by amide formation (Scheme I).The acid 2 was prepared (23percent yield) from 6-methyluracil (12) by coupling the aldehyde 19 with the phosphorane 20 (Scheme III).The synthesis of the amine 3, especially challenging because of the monoxodithioacetal moiety, was accomplished by the reaction of a cysteine α-halo sulfoxide derivative 8 with sodium methylmercaptide (Scheme II, route B).Alternatively, oxidation of the dithioacetals 23-26 was unsatisfactory, yielding predominantly the undesired regioisomers 27B-30B (Table I).Procedures are given for the preparation and separation of the α-halo sulfoxide diastereomers 33,35, 36-41, and 52-54.By use of these procedures, the amino alcohol monoxodithioacetals 3 and 60 were prepared in five steps (40percent yield) from the D-cystine derivative 59 having the SC chirality of sparsomycin (Scheme VII).Finally, sparsomycin (1) and the SC diastereomer 67 were prepared (40percent yield) by mixed anhydride coupling of 2 with 3 and 60, respectively (Schemes I and X).In addition, syntheses of the RC enantiomer 65 and corresponding diastereomer 66 are described (Scheme IX).The CD spectra of 1 and its three stereomers are also discussed.
- Ottenheijm, Harry C.J.,Liskamp, Rob M.J.,Nispen, Simon P.J.M. van,Boots, Hans A.,Tijhuis, Marian W.
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p. 3273 - 3283
(2007/10/02)
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