- volution of Hydrogen in the Reaction of Hydroheteroaromatic Compounds with Dehydrogenating Agents
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The yields of molecular hydrogen in the reactions of benzimidazolines 1,2-dihydropyrimidines with a number of dehydrogenating agents have been determined.The formation of hydrogen is due to breakdown of the cation-radicals of the hydrohetarenes formed in
- Morkovnik, A. S.,Ivakhnenko, E. P.,Bogachev, Yu. G.,Tertov, B. A.,Berberova, N. T.,Okhlobystin, O. Yu.
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- Metalation of Aryl-bis(3-alkyl-5-methylpyrazol-1-yl)- methane (Alkyl=Me, Ad; Aryl=Ph, C6H4-2?OH) with NaN(SiMe3)2, KN(SiMe3)2, and Ca{N(SiMe3)2}2
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Deprotonation of phenyl-bis(3,5-dimethylpyrazolyl)methane (HC(Ph)(PzMe2)2, 1 a) with [(thf)2Ca{N(SiMe3)2}2] in THF at ?40 °C yields heteroleptic [(thf)2Ca{N(SiMe3)2}{C(Ph)(PzMe2)2}] (2 a) and finally homoleptic [(thf)Ca{C(Ph)(PzMe2)2}2] (2 b). However, these complexes degrade at room temperature to calcium bis(pyrazolate) and 2-phenyl-4,6-dimethylpyrimidine (3 a). This degradation is accelerated when bulky phenyl-bis(3-adamantyl-5-methylpyrazolyl)methane (HC(Ph)(PzAd,Me)2, 1 b) is treated similarly and 2-phenyl-4-adamantyl-6-methylpyrimidine (3 b) forms quickly. Sodiation of 1 a and 1 b with NaN(SiMe3)2 yields [{HC(Ph)(PzMe2)2}Na{C(Ph)(PzMe2)2}] (4 a) and [{HC(Ph)(PzAd,Me)2}Na{C(Ph)(PzAd,Me)2}] (4 b). The stronger metalation reagent benzylpotassium is able to quantitatively deprotonate 1 b leading to dinuclear [K{C(Ph)(PzAd,Me)2}]2 (4 c). The metathetical approach and the reaction of 4 c with metal(II) halides of Mg, Ca and Zn again leads to degradation and formation of pyrimidine 3 b. This decomposition of the ligand can be circumvented when the sidearm contains the anionic charge. Thus, 2-hydroxyphenyl-bis(3-adamantyl-5-methylpyrazol-1-yl)methane (1 c) reacts with [(thf)2Ca{N(SiMe3)2}2] in THF to the homoleptic complex [(thf)4Ca{O?C6H4?CH(PzAd,Me)2}] (2 c). In this complex, THF and pyrazolyl bases compete in the coordination sphere and preparation of a heteroleptic complex fails. To avoid the binding competition between THF and pyrazolyl bases and to stabilize heteroleptic calcium complexes, the reaction has been repeated in toluene yielding [Ca{N(SiMe3)2}{O?C6H4?CH(PzAd,Me)2}]2 (2 d).
- G?rls, Helmar,Krieck, Sven,Müller, Christoph,Mandel, Miles J.,Westerhausen, Matthias
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- Electronic absorption and emission properties of bishydrazone [2?×?2] metallosupramolecular grid-type architectures
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Several ditopic ligands containing two tridentate bishydrazone coordination subunits and their Zn(II) and Cd(II) [2 × 2] grid-type complexes were prepared and their photoluminescent properties studied. A special attention was devoted to the influence of the orientation of the hydrazone group N–N[dbnd]in the core of the ligands and their complexes. Its reversal from [pyridine[dbnd]N–N–pyrimidine] (L1) to [pyridine–N–N[dbnd]pyrimidine] (L2) has a strong impact on the observed absorption and emission behaviour of particular ligands (L1 and L2) as well as of their [2 × 2] grid assemblies. The further lateral functionalization of the ligands led to different emission quantum yields of the resulting grids, while their emission and absorption spectra varied very little. The simplest derivative L1 turned out to have the best performance with, for its Zn(II) complex, relatively high quantum yield 60%.
- Holub, Jan,Santoro, Antonio,Lehn, Jean-Marie
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supporting information
p. 223 - 231
(2019/06/07)
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- The phosphorescent pyrimidine iridium complex production device
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The invention belongs to the technical field of chemical engineering equipment, and relates to a device for producing a phosphorescent pyrimidine iridium complex. The device comprises a reactor, wherein a reflux cooling pipe is connected to the top of the reactor and is connected with a condenser; the condenser is connected with one end of a U-shape tube, and the other end of the U-shaped tube is connected to the top of the reactor; the bottom of the U-shaped tube is connected to the top of a rinsing tank; the reactor is connected with a nitrogen storage tank; the bottom of the reactor is successively connected with a filter and a first pump; the first pump is respectively connected to the top of the rinsing tank and the top of an ester washing tank; the bottom of the rinsing tank is connected to the top of the ester washing tank; the bottom of the ester washing tank is connected with the top of a chromatographic column the bottom of which is connected with a concentrator; and the concentrator is connected with a dryer. The device is designed specially for producing a phosphorescent pyrimidine iridium complex, the reaction process is sealed and safe, and operations of multiple suction filtering, rinsing, organic solvent cleaning, chromatography and concentration drying can be finished, thus all production steps can be completed in one device.
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Paragraph 0030; 0031
(2018/04/01)
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- Iron Catalysis for Modular Pyrimidine Synthesis through β-Ammoniation/Cyclization of Saturated Carbonyl Compounds with Amidines
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An efficient method for the modular synthesis of various pyrimidine derivatives by means of the reactions of ketones, aldehydes, or esters with amidines in the presence of an in situ prepared recyclable iron(II)-complex was developed. This operationally simple reaction proceeded with broad functional group tolerance in a regioselective manner via a remarkable unactivated β-C-H bond functionalization. Control experiments were performed to gain deep understanding of the mechanism, and the reactions are likely to proceed through a designed TEMPO complexation/enamine addition/transient α-occupation/β-TEMPO elimination/cyclization sequence.
- Chu, Xue-Qiang,Cao, Wen-Bin,Xu, Xiao-Ping,Ji, Shun-Jun
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p. 1145 - 1154
(2018/06/18)
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- Novel multi-component syntheses of pyrimidines using β-CD in aqueous medium
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Using β-cyclodextrin (β-CD) as a catalyst pyrimidine derivatives were synthesized for the first time in aqueous medium. β-CD is a recyclable, inexpensive, economically viable, non-toxic, and readily available material. Various aldehydes were used with amm
- Rakhi, Chowrasia,Ramesh, Katla,Darbem, Mariana P.,Branquinho, Tabata A.,De Oliveira, Aline Rufino,Manjari, Padma Sunitha,Domingues, Nelson Luís C.
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supporting information
p. 1656 - 1660
(2016/04/04)
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- Greener [3+3] tandem annulation-oxidation approach towards the synthesis of substituted pyrimidines
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An economical and green synthesis of partly and fully substituted pyrimidines is described using α,β-unsaturated ketones and benzamidine hydrochloride using greener and recyclable choline hydroxide (ChOH) as both a catalyst and a reaction medium. The remarkable features of this method are mild reaction conditions, short reaction times, easy workup procedure, recyclability of the catalyst and excellent yields of the products. The reaction involves a [3+3] annulation-oxidation sequence and the protocol is useful for synthesizing a broad range of biologically significant pyrimidine derivatives.
- Vadagaonkar, Kamlesh S.,Kalmode, Hanuman P.,Prakash, Sattey,Chaskar, Atul C.
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p. 3639 - 3645
(2015/05/20)
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- Metal-free synthesis of 2,4,6-trisubstituted pyrimidines using α,β-unsaturated ketones and benzamidine via tandem annulation-oxidation pathway
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A tandem metal-free synthesis of partly and fully substituted pyrimidines has been accomplished from α,β-unsaturated ketones and benzamidine in presence of triethyl amine. The reaction proceeds via [3+3] annulation-oxidation sequence and the protocol has
- Vadagaonkar, Kamlesh S.,Kalmode, Hanuman P.,Murugan, Kaliyappan,Chaskar, Atul C.
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p. 447 - 458
(2015/07/28)
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- Ligand-accelerated iron- and cobalt-catalyzed cross-coupling reactions between N-heteroaryl halides and aryl magnesium reagents
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Quinoline and isoquinoline dramatically increase the rate and yield of Fe- and Co-catalyzed cross-coupling reactions. This new catalytic process extends the scope of such cross-coupling reactions to include complex functional groups and allows heteroaryl-
- Kuzmina, Olesya M.,Steib, Andreas K.,Markiewicz, John T.,Flubacher, Dietmar,Knochel, Paul
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supporting information
p. 4945 - 4949
(2013/06/04)
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- Iron-catalyzed cross-coupling of N-heterocyclic chlorides and bromides with arylmagnesium reagents
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A simple, practical iron salt catalyzed procedure allows fast cross-couplings of N-heterocyclic chlorides and bromides with various electron-rich and -poor arylmagnesium reagents. A solvent mixture of THF and tBuOMe is found to be essential for achieving high yields mainly by avoiding homocoupling side reactions.
- Kuzmina, Olesya M.,Steib, Andreas K.,Knochel, Paul,Flubacher, Dietmar
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supporting information
p. 4818 - 4821,4
(2012/12/12)
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- An expeditious route toward pyrazine-containing nucleoside analogues
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An improved and convenient methodology for the synthesis of asymmetrically substituted pyrazines starting from 3,5-dichloropyrazin-2(1H)-ones has been elaborated. Several nucleoside analogues have been synthesized containing the pyrazine core as the organic base coupled with the sugar via a triazole linkage. The beneficial effect of microwave irradiation throughout the sequence has been demonstrated.
- Modha, Sachin G.,Trivedi, Jalpa C.,Mehta, Vaibhav P.,Ermolat'ev, Denis S.,Van Der Eyckens, Erik V.
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supporting information; experimental part
p. 846 - 856
(2011/04/17)
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- Helicity-encoded molecular strands: Efficient access by the hydrazone route and structural features
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Control over the folding of molecular strands may be achieved by appropriate choice of the constituting subunits, in particular for chains of specific heterocycles such as sequences of directly connected pyridine (py) and pyrimidine (pym) rings, which are known to fold into extended helical structures. Since the hydrazone (hyz) group represents an isomorphic analogue of a py site, the condensation of hydrazine and carboxaldehyde derivatives of pym offers a very efficient approach to strands incorporating hyz instead of py units and constituted by sequences of alternating hyz and pym group. A. series of such strands of different lengths, up to ten hyz units, i.e., 1-7, were synthesized. Their spectral properties indicate that they fold indeed into helical shapes. Extensive characterization was performed in solution by IH-NMR spectroscopy and in the solid state by determination of the crystal structures of eight such strands. They all display the expected helical geometry with up to 3 1/3, turns and direct stacking contacts. The efficiency and flexibility of the synthetic approach as well as its wide potential for generation of diversity through lateral decoration make the (hyz - pym) subunit a particularly attractive helicity codon.
- Schmitt, Jean-Louis,Stadler, Adrian-Mihail,Kyritsakas, Nathalie,Lehn, Jean-Marie
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p. 1598 - 1624
(2007/10/03)
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- Pyrolysis of 1-substituted pyrazoles and chloroform at 550°C: Formation of α-carboline from 1-benzylpyrazoles
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Pyrolysis of 13CH3 labelled 1-methylpyrazole 8 with chloroform at 550°C in a continuous flow reactor yields unlabelled 2-chloropyrimidine 9 and 2-cyanopyrrole 10 labelled at the cyano group. However, pyrolysis of 1-benzylpyrazole 14 with chloroform under similar conditions gives 9,2-phenylpyrimidine 13 and, as the major product, α-carboline 15. Pyrolysis of several substituted 1-(arylmethyl)pyrazoles and the use of 13C and 15N labelled compounds provides direct evidence by which the positions of 7 atoms of 1-benzylpyrazole can be located in the α-carboline. These data support the mechanisms suggested for the formation of 9, 10, and 15.
- Bhatti, Inayat A.,Busby, Reginald E.,Bin Mohamed, Murtedza,Parrick, John,Shaw, C. J. Granville
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p. 3581 - 3585
(2007/10/03)
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- Preparation of ?-Deficient Heteroarylzinc Halides by Oxidative Addition of Active Zinc and Its Palladium-Catalyzed Reaction
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The oxidative addition of active zinc to iodo- and bromo-substituted ?-deficient heteroarenes such as pyridine, pyrimidine, and quinoline gave the corresponding heteroarylzinc halides which were transformed to the arylated and benzoylated derivatives by palladium-catalyzed reaction.
- Sakamoto, Takao,Kondo, Yoshinori,Murata, Naoko,Yamanaka, Hiroshi
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p. 9713 - 9720
(2007/10/02)
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- Pyridine and pyrimidine ring syntheses from 4-(4-morpholino)-3-pentenone and from ethyl 3-(4-morpholino)-2-butenoate
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3-Substituted 2(1H)-pyridones are produced from reaction of 4-(4- morpholino)-3-pentenone 1 with each of the following carbon acids: cyanoacetamide, malononitrile, cyanothioacetamide, acetylacetamide, benzoyl- acetonitrile. Reaction of ethyl 3-(4-morpholino)-2-butenoate 2 with cyanoacetamide gives the corresponding hydroxypyridone. Pyrimidines are formed by reaction of 1 and of 2 with benzamidine and with S-benzylthiourea; in the last case, the eliminated morpholine displaces the benzylthio group to give the final product.
- Ratemi,Namdev,Gibson
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p. 1513 - 1516
(2007/10/02)
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- Studies on Pyrimidine Derivatives. XLI.1) Palladium-Catalyzed Cross-Coupling Reaction of Halopyrimidines with Aryl- and Vinyltributylstannanes
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The arylation of 2-, 4-, and 5-halopyrimidines with aryltributylstannanes in the presence of dichlorobis(triphenylphosphine)palladium was investigated with successful results.The reaction can be expanded to the synthesi of 2-, 4-, and 5-vinylpyrimidines w
- Kondo, Yoshinori,Watanabe, Ry,Sakamoto, Takao,Yamanaka, Hiroshi
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p. 2814 - 2816
(2007/10/02)
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- Hexacarbonylmolybdenum-Induced N-N Bond Cleavage of Pyrazoles. Conversion of 1-Acylpyrazoles to Pyrimidines
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-induced reactions of 1-acyl-3,5-disubstituted pyrazoles underwent N-N bond cleavage and subsequent cyclocondensation to give pyrimidines as well as deacylation to give 3,5-disubstituted pyrazoles.Under similar conditions, 1,3,5-trisubstituted pyrazoles, which have no electron-withdrawing substituent on N1, gave no product, except for the starting materials.
- Nitta, Makoto,Hamamatsu, Tatsuo,Miyano, Hiroyuki
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p. 4473 - 4475
(2007/10/02)
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- A C-13 nuclear magnetic resonance study of the pyrimidine synthesis by the reactions of 1,3-dicarbonyl compounds with amidines and ureas
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The detailed mechanistic pathways are elucidated for the reactions of acetylacetone, methyl acetoacetate, and dimethyl malonate with a variety of amidines and ureas.In many cases the identification of a single intermediate allows the definition of the reaction path and identification of two steps.Intermediates characterized include ring-closed dihydroxytetrahydropyrimidines, dihydrohydroxypyrimidinones, open-chain enamides, and carbonyl addition compounds.
- Katritzky, Alan R.,Yousaf, Taher I.
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p. 2087 - 2093
(2007/10/02)
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- Reactions of β-Sulfenyl α,β-Unsaturated Ketones with Guanidine, Amidines and Diamines
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β-Sulfenyl α,β-unsaturated ketones 1a-c reacted with guanidine or amidines to give pyrimidine derivatives 3 in 14-76percent yields.Treatment of ketones 1 with diamines such as ethylenediamine and o-phenylenediamine afforded the seven-membered heterocycles, 2,3-dihydro-1,4-diazepine 5 and 2,3-benzo-1,4-diazepines 8a-c.
- Nishio, Takehiko,Tokunaga, Tatsuhiro,Omote, Yoshimori
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p. 405 - 407
(2007/10/02)
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- A NOVEL CONVENIENT ONE STEP PYRIMIDINE SYNTHESIS
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A new method for the preparation of pyrimidines by condensation of β-dicarbonyl compounds, ammonium salts and carbonyl containing substances has been developed.
- Weis, A. L.,Rosenbach, V.
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p. 1453 - 1454
(2007/10/02)
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