- Alumina Catalyzed Synthesis of Fused Thioxopyrimidine Derivatives under Microwaves
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An expeditious solventless approach for the synthesis of pyrazolino[3,4-d]/isoxazolino[3,4-d]/pyrano[2,3-d]/iminopyrimidino[4,5-d]/ thioxopyrimidino[4,5-d]/thiazino[5,4-d] pyrimidines from 2-thiobarbituric acid using supported reagents (acidic/basic alumi
- Kidwai,Mohan,Rastogi
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- Properties of a furan ring-opening reaction in aqueous micellar solutions for selective sensing of mesalazine
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A novel and efficient non-azo formation based method was developed for trace sensing of mesalazine (MES), a pharmaceutical aromatic amine. MES was simply coupled with a Meldrum's activated furan (MAF) reagent via a furan ring opening reaction to form a colored product. The intense purple colored solution was detected at 575 nm. The reaction of MES with MAF was monitored by employing 1H NMR spectroscopy and mass spectrometry. In addition, density functional theory (DFT) was applied to optimize the structure of the colored product and its λmax (the wavelength of maximum absorbance) in dimethyl sulfoxide and water. The colored product was considered in three possible structures, and the most possible structures in dimethyl sulfoxide and in water were identified by employing the DFT calculations. Both of the most possible structures indicated only a local excitation in their λmax and no charge transfer was observed. However, one of the structures in dimethyl sulfoxide presented charge transfer properties occurring through N–C[dbnd]C–C moiety. A univariate optimization method was also used to attain the optimum condition for analysis. In addition, the dependence of the analytical response on the three main affecting parameters (reaction time (X1), Triton X-100 concentration (X2) and MAF concentration (X3)) was identified by employing a central composite design (CCD) approach. The CCD study showed that the analytical response depends complexly on the parameters. Beer's law was obeyed within the range of 0.06–9.30 μg mL?1 of MES (155 fold linearity) at 575 nm, under the optimum condition introduced by the CCD approach. Also, the limit of detection was obtained 0.04 μg mL?1 of MES. The method showed precision (as relative standard deviation) and accuracy (as recovery) within the ranges of 0.6–3.2 % and 96.3–100.8%, respectively. Various organic and inorganic species, amino-pharmaceuticals, and amino acids were tested to evaluate the selectivity of the method. The selectivity of the analytical method was satisfactory. The method was successfully applied for detection of MES in various water matrices and pharmaceutical tablets.
- Sabahi-Agabager, Leila,Eskandari, Habibollah,Nasiri, Farough,Shamkhali, Amir Nasser,Baghi Sefidan, Somayyeh
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- Facile syntheses of bioactive 5-arylidenethiobarbituric acids
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A simple and green chemistry route for the preparation of 5-arylidenethiobarbituric acids has been developed by Knoevenagel condensation of thiobarbituric acid with different aromatic and heteroaromatic aldehydes using catalytic amount of acetic acid by g
- Sharif, Ahsan,Ahmed, Ejaz,Munawar, Munawar Ali,Jabeen, Shamsa,Khan, Misbah-Ul-Ain,Begum, Robina,Farrukh, Aleeza,Ashraf, Muhammad,Arshad, Shafia,Afza, Nighat
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experimental part
p. 578 - 586
(2012/01/05)
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- New strategy for the synthesis of 5-Aryl-1H,1′H-spiro[furo[2,3-d] pyrimidine-6,5′-pyrimidine]2,2′,4,4′,6′(3H,3'H,5H) -pentaones and their sulfur analogues
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Reaction of barbituric acid (BA), 1,3-dimethyl barbituric acid (DMBA) and 2-thiobarbituric acid (TBA) with cyanogen bromide and aldehydes in the presence of L-(+)-tartaric acid afforded a new route for the synthesis of stable heterocyclic 5-aryl-1H,1′H-spiro[furo[2,3-d]pyrimidine-6,5′- pyrimidine]2,2′,4,4′,6′(3H,3′H,5H)- pentaones which is a dimeric form of barbiturate (uracil and thiouracil derivative). In the reaction of 1,3-diethyl thiobarbituric acid (DETBA) the Knoevenagel condensation and then Michael adducts were obtained under the same condition. Structure elucidation is carried out by 1H NMR, 13C NMR, FT-IR and Mass analyses. Mechanism of the formation is discussed.
- Jalilzadeh, Mohammad,Pesyan, Nader Noroozi
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experimental part
p. 3382 - 3388
(2012/01/19)
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- A green approach to the synthesis of fused uracils: Pyrano[2,3-d] pyrimidines. On-water one-pot synthesis by domino Knoevenagel/Diels-Alder reactions
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On-water Knoevenagel condensations of 2-thiobarbituric acid and N,N-dimethylbarbituric acid with aromatic and heteroaromatic aldehydes were carried out without a catalyst and at room temperature. Condensations in aqueous suspensions occurred rapidly, giving excellent yields. Solvent-free hetero-Diels-Alder reactions of 5-arylidene derivatives of barbituric acids with ethyl vinyl ether were investigated at room temperature and pyrano[2,3-d]pyrimidines of potential pharmacological activity were obtained in excellent yields. Three-component one-pot syntheses of annulated uracils were performed in aqueous suspensions. Reactions of barbituric acids, aldehydes, and ethyl vinyl ether were carried out at ambient temperature, whereas the one-pot synthesis with barbituric acids, aldehydes, and styrene or N-vinyl-2- oxazolidinone required the heating of aqueous suspensions at 60°C. On-water cycloadditions were characterized by high diastereoselectivity in contrast to reactions carried out in homogeneous organic media (dichloromethane, toluene). They allowed the cis adducts to be obtained preferentially or exclusively. The presented green methods avoid the use of catalysts, the heating of reaction mixtures for long times at high temperatures, and the use of organic solvents, and make the synthesis of a variety of pyrano[2,3-d]pyrimidines chemically efficient. The results reveal water as the medium of choice for the examined cycloadditions. Georg Thieme Verlag Stuttgart - New York.
- Paasz, Aleksandra
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experimental part
p. 4021 - 4032
(2011/02/21)
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- Barbituric acid analogs as therapeutic agents
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This invention pertains to active barbituric acid analogs which inhibit HIF-1 activity (e.g., the interaction between HIF-1α and p300) and thereby inhibit angiogenesis, tumorigensis, and proliferative conditions, such as cancer. The present invention also
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