Neste trabalho pós de CaCu3Ti4O12 foram preparados por reação em estado sólido e por técnicas de solução: complexação de cátions e coprecipitação dos oxalatos. Foram realizados estudos de formação de fase, densificação e propriedades dielétricas das cerâmicas sinterizadas. Para efeito comparativo, ta is propriedades foram determinadas em amostras puras e contendo dissilicato de lítio (LSO) e fluoreto de lítio (LiF) como aditivos de sinterização. O principal objetivo foi verificar o efeito do uso dos diferentes aditivos de sinterização na microestrutura, densificação e propriedades dielétricas do CCTO. Os principais resultados revelaram que pós preparados por técnicas de solução apresentam fase única após calcinação em condições selecionadas. Foi verificado que os aditivos influenciam na densificação, possibilitando obter cerâmicas com 95% da densidade teórica do CCTO a 1025°C. As amostras preparadas por diferentes técnicas apresentam propriedades similares, com exceção das características microestruturais. A permissividade elétrica determinada à temperatura ambiente é da ordem de 104 independentemente do método de síntese. As menores perdas dielétricas foram obtidas para amostras contendo LiF como aditivo de sinterização. / In this work the effects of the method of synthesis and sintering additives on the microstructure and dielectric properties of CCTO were investigated. Powder mixtures were prepared by the cation complexation and coprecipitation methods, and by mixing of the starting oxides, for comparison purposes. Lithium dissilicate (LSO) and lithium fluoride (LiF) were used as sintering aids. The main results revealed that powders prepared by solution techniques have single phase after calcination at selected conditions. The additives were found to influence the densification allowing for obtaining high relative density (≥ 95%) at 1025ºC. Specimens prepared by different methods show similar properties except on microstructure features. The electric permittivity is of the order of 104 for all investigated specimens independent on the method of synthesis. The dielectric loss is found to be lower for specimens prepared with LiF as sintering aid.

A síntese de nanopartículas com morfologia controlada vem sendo objeto de interesse crescente no campo da Ciência dos Materiais. Devido a essa motivação, o principal objetivo desse trabalho foi a síntese e caracterização de pseudoboemita e boemita apresentando uma ou duas dimensões nanométricas. O método de síntese utilizado para a obtenção de pseudoboemita fibrilar é baseado na reação de um alcóxido de alumínio, em solução aquosa de ácido acético. Para a preparação de boemita, um único método de síntese, a síntese hidrotérmica, foi utilizado, com o emprego de três precursores: uma pseudoboemita, um sal orgânico (o monohidróxido diacetato de alumínio) e o trihidróxido de alumínio gibsita, este último em duas formas: uma gibsita comercial e uma gibsita sintetizada que utiliza iodo como ativador. As pseudoboemitas e as boemitas obtidas foram caracterizadas por difração de raios-X e microscopia eletrônica de varredura. Algumas amostras de pseudoboemita e de boemita foram caracterizadas por análise térmica diferencial e por espectroscopia vibracional na região do infravermelho. Foram obtidas pseudoboemitas com morfologia fibrilar (partículas anisométricas alongadas); no caso das boemitas foram produzidas distintas morfologias (de acordo com o precursor e com as condições de síntese empregadas em sua obtenção): fibrilar (duas dimensões em escala nanométrica), nanoplacas (uma dimensão em escala nanométrica) e partículas com simetria cúbica (nenhuma dimensão em escala nanométrica). A presença do íon acetato na síntese hidrotérmica foi determinante na formação de boemita com morfologia de placas. / The synthesis of nanoparticles with controlled morphology is of increasing interests in the field of Materials Science. Due to this motivation, the main objective was the synthesis and characterization of boehmite pseudoboehmite presenting one or two nanoscale dimensions. The method of synthesis used to obtain fibrillar pseudoboehmite is based on the reaction of an aluminum alkoxide in aqueous acetic acid. For the preparation of boehmite, a single synthesis method, the hydrothermal synthesis, was used with three different precursors: a pseudoboehmite, an organic salt (aluminum monohydroxide diacetate) and the aluminum trihydroxide gibbsite, the latter in two forms: a commercial gibbsite and a gibbsite synthesized that utilizes iodine as activator. The pseudoboehmites and boehmites obtained were characterized by X-ray diffraction and scanning electron microscopy. Some samples of pseudoboehmite and boehmite were characterized by differential thermal analysis and by vibrational spectroscopy in the infrared region. Pseudoboehmites were obtained with fibrillar morphology (anisometric elongated particles); for boehmites, different morphologies were produced (according to the precursor and the synthesis conditions employed in their production): fibrillar (two dimensions in nanoscale), nanoplates (one dimension in nanoscale) and particles with cubic symmetry (no dimensions in nanoscale). The presence of acetate ion in hydrothermal synthesis was instrumental in the formation of boehmite with plate morphology.

O objetivo deste estudo foi sintetizar e caracterizar monômeros metacrilamidas, desenvolver, caracterizar e avaliar as propriedades de sistemas adesivo convencional de três passos. Foram sintetizadas bis(metacrilamida)s e tris(metacrilamida) e caracterizadas por espectroscopia de Infravermelho por Transformada de Fourier (FTIR), Ressonância Magnética Nuclear (RMN) de 1H e 13C, por Cromatografia Líquida de Alta Eficiência com Espectrometria de Massas (UHPLC-QTOF-MS) e Calorimetria Exploratória Diferencial Modulada (MDSC). Quatro bis(metacrilamidas), (1) N,N’-(propane-1,3-diyl)bis(N-ethyl-2-methylacrylamide), (2) N,N’-(octane-1,8-diyl)bis(2-methylacrylamide), (3) N,N’-(butane-1,4-diyl)bis(2-methacrylamide) e (4) N,N’-(1,4 phenylene)bis(2-methylacrylamide)monômero (1), (2), (3) e (4), e uma tris(metacrilamida) TMA, foram sintetizadas. Pela análise de FTIR-ATR foram observadas as bandas correspondentes ao estiramento do grupo C=O (1660 cm-1), C=C (1610 cm-1), N-H (3300 cm-1) e C-N (1520 cm-1). As análises de RMN identificaram a presença das ligações duplas referentes aos grupos metacrilamidas em deslocamentos químicos entre 5,3 e 5,8 ppm para 1H e entre 120 e 140 ppm para 13C.Os valores de massa exata m/z foram: 267,2068, 281,2222, 225,1595, 245,1283 e 351,2385 g/mol para os monômeros (1), (2), (3), (4) e TMA, respectivamente. A cinética de polimerização do TMA e dos adesivos experimentais contendo 2-hidroxietil acrilamida (HEAA) ou 2-hidroxietil metacrilato (HEMA) com as seguintes formulações foram investigadas por meio de DSC-PCA, n=3: TMA33%/HEAA66%, TMA50%/HEAA50%, TMA66%/HEAA33%, TMA50%/HEMA50%, BisGMA/HEAA/TMA e BisGMA/HEMA.Características e propriedades mecânicas das resinas adesivas BisGMA/HEAA/TMA e BisGMA/HEMA foram avaliadas por resistência coesiva (UTS, n=5), degradação em solvente (ΔKHN, n=5), ângulo de contato (n=5), microtração (μTBS, n=20) e análise de fratura. Um primer a base de acrilamidas foi desenvolvido (H2O/HEAA/AMPS) (2-acrylamida-2-methilpropano ácido sulfônico) para ser utilizado no grupo experimental com metacrilamidas. Os valores de pH e ângulo de contato do primer experimental foram comparados com o primer do ScotchBond Multi-purpose (grupo controle). O monômero (1) resultou em um monômero amarelo claro de baixa viscosidade, entretanto, não apresentou foto ou termopolimerização. A energia de ativação determinada pelo método de Kissinger foi – 165,8 kJmol-1; -182,7 kJmol-1 e -156,7 kJmol-1 para os monômeros (2), (3) e (4), respectivamente. Sistemas adesivos convencionais de três passos a base de metacrilamidas e a base de metacrilatos foram desenvolvidos. Resinas adesivas contendo somente HEAA e TMA (TMA33%/HEAA66%, TMA50%/HEAA50%, TMA66%/HEAA33%) apresentaram grau de conversão abaixo de 40% após 40 s de fotoativação. Alto grau de conversão (acima de 60%) só foi encontrado para as resinas adesivas BisGMA/HEAA/TMA e BisGMA/HEMA e sem diferença significativa entre elas, p>0,05. Os valores de UTS (BisGMA/HEMA- 67,7 ±5 MPa e BisGMA/HEAA/TMA- 60,5 ±7 MPa), μTBS (BisGMA/HEMA- 57 ± 14 MPa e BisGMA/HEAA/TMA- 53,1 ±15 MPa) e ângulo de contato (BisGMA/HEMA- 39,5 ±9 e BisGMA/HEAA/TMA- 46,7 ±15) não apresentaram diferença estatística, p>0.05. O primer experimental apresentou um valor pH mais baixo (2,7) bem como de ângulo de contato (18,5 ±5) em relação ao comercial (pH-4 e θ-33,5 ±4). A síntese proposta para os monômeros (1), (2), (3), (4) e TMA foi caracterizada nesse trabalho. Um primer somente com acrilamidas foi desenvolvido e a presença do novo monômero TMA na resina adesiva BisGMA/HEAA permitiu a formulação de um sistema adesivo convencional de três passos sem a presença do monômero HEMA. / The aim of this study was synthesized and characterizes methacrylamides monomers, development, characterizer and evaluated the properties of 3-step etch-and-rise adhesive system. Bis(methacrylamide)s and tris(methacrylamide) were synthesized. The monomer structures were confirmed by 1H and 13C Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR-ATR), Ultra-high liquid chromatography quadrupole time of flight mass spectrometry (UHPLC-QTOF-MS) and modulated differential scanning calorimetry (mDSC). Four bis(methacrylamide)s monomers (1) N,N’-(propane-1,3-diyl)bis(N-ethyl-2-methylacrylamide), (2) N,N’-(octane-1,8-diyl)bis(2-methylacrylamide), (3) N,N’-(butane-1,4-diyl)bis(2-methacrylamide) and (4) N,N’-(1,4 phenylene)bis(2-methylacrylamide) and one tris(methacrylamide), TMA, were synthesized. All IR spectra of the monomers showed the C=C axial deformation at 1610 cm-1. The 1H NMR spectra the olefinic hydrogens were observed at 5.3 an 5.8 ppm and in the 13C NMR, the vinylic carbons at 120 and 140 ppm. The exact m/z values were: 267.2068, 281.2222, 225.1595, 245.1283 and 351.2385 g/mol for monomers (1), (2), (3), (4) and TMA respectively. Monomer (1) not presented photo (DSC-PCA) or thermal polymerization. The activation energy determined using Kissinger methodology was: - 165.8 kJmol-1; -182.7 kJmol-1 and -156.7 kJmol-1 for monomers (2), (3) and (4), respectively. 3-step adhesive systems with methacrylamides and methcrylates were development. Kinetics of photopolymerization of TMA and experimental adhesive resin containing 2-hydroxyethylacrylamide (HEAA) or 2-hydroxyethylmethacrylate (HEMA) in the following formulations: (TMA 33%/HEAA 66%, TMA 50%/HEAA 50%, TMA66%/HEAA33%, TMA50%/HEMA50%, BisGMA66%/HEAA24%/TMA10% and BisGMA66%/HEMA33%) were investigated through DSC-PCA. Characteristics and mechanical properties for BisGMA 66%/HEAA 24%/TMA 10% and BisGMA 66%/HEMA 33% adhesives were evaluated with ultimate tensile strength (UTS, n=5), softening in solvent (ΔKHN, n=5), contact angle (n=5), microtensile bond strength (μTBS, n=20) and failure analysis. A primer was also formulated with H2O/HEAA/AMPS (2-acrylamido-2-methylpropane sulfonic acid) and the pH and contact angle value were verified and compared to commercial ScotchBond primer. Adhesive resin with HEAA and TMA (TMA33%/HEAA66%, TMA50%/HEAA50%, TMA66%/HEAA33%) showed lower conversion and polymerization rate after 40 s of light activation. Higher conversion (up to 60%) was found for BisGMA/HEAA/TMA and BisGMA/HEMA adhesive resin without significant difference between adhesive resin, p>0.05. UTS (BisGMA/HEMA- 67.7 ±5 MPa e BisGMA/HEAA/TMA- 60.5 ±7 MPa), immediate μTBS (BisGMA/HEMA- 57 ± 14 MPa e BisGMA/HEAA/TMA- 53.1 ±15 MPa), ΔKHN (BisGMA/HEMA- 56 ± 7 e BisGMA/HEAA/TMA- 64 ±4) and contact angle (BisGMA/HEMA- 39.5 ±9 e BisGMA/HEAA/TMA- 46.7 ±15) showed no statistical difference, p>0.05. The experimental primer presented more acidity pH (2.7) and lower contact angle (18.5 ±5) when compared to commercial primer (pH- 4 e θ- 33.5 ±4). A new acrylamide based-primer was formulated and the presence of the new tris(methacrylamide) monomer (TMA) was enable the preparation of a 3-step etch-and-rise adhesive system without HEMA monomer.

by Wing Shun Cheung. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (p. 159-178). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Processing of nanostructured WC-Co and W-Co powders,modelling of Fe-Mn-Si alloy, swelling of Fe-Cu alloy, andmechanical properties and sintering of Fe-Mn-Si steels havebeen studied in the present thesis. W-Co precursors made by chemical synthesis were used toproduce nanostructured WCCo and W-Co powders by calcination,reduction and carburization. The phase constituents in thecalcined powders depend on temperature and atmospheres. Cobaltcan accelerate the reduction rate of the W-Co precursors as acatalyst, and cobalt influences the formation of intermediatephases during the reduction of the precursors. The ratio of carbon monoxide to carbon dioxide controlscarburization process, gives different intermediate phases andcarburization rates. There exist several intermediate phases: W6Co6C, W3Co3C, W2C due to varying carbon monoxide content in thecarburization gases. Nanostructured WC-Co powders with aparticle size of 20-50 nm have been obtained. The effect of silicon content on the particle sizedistribution of milled Fe-Mn-Si master alloy powders is muchmore significant than that of manganese content. A finer finalparticle size can be obtained in the alloy powders with highersilicon compositions. Long time milling results in theagglomeration of small particles. The grinding process can bedescribed using classic batch grinding equation based on thepopulation balance model. A swelling model for Fe-Cu alloyssintered at the temperatures above the melting point of copperhas been established based on the penetration mechanism. In themodel, the particle coordination number and heating rate wereused to express the porosity and the thickness of the diffusionlayers between iron and copper particles respectively. The effects of sintering temperature and time on theproperties of sintered steels have been studied. Fe-Mn-Simaster alloys made by cast-milling, atomizing, and acombination of atomization and milling have been covered. Themilled, and atomizationmilled alloy steels showed goodmechanical properties with small dimensional change. Transientliquid phase of the Fe-Mn-Si alloys accelerates densification,and offer fast diffusion of alloying elements. The addition ofa small amount of Fe-Mn-Si master alloy to Astaloy 85Mo powdercan lead to high strength with zero dimensional change. <b>Key words:</b>Processing; Modelling; Nanostructured powder;WC-Co; W-Co; Calcination; Reduction; Carburization; Particlesize; Sintered steel; Fe-Cu alloy; Swelling; Fe-Mn-Si masteralloy; Mechanical properties; Sintering parameters.

The present work reports a study of mechano-chemical synthesis (MCS) and mechano-chemical activation synthesis (MCAS) of nanostructured hydrides in the Mg-H, Mg-Al-H and Mg-B-H systems by controlled reactive mechanical alloying/milling (CRMA/CRMM) in the magneto-mill Uni-Ball-Mill 5. Regardless of the hydride systems, the morphologies of milled Mg-H, Mg-Al-H and Mg-B-H powders after a prolonged milling time can be characterized by dramatic particle size refinement and high tendency to form agglomerates. In the Mg-Al-H system, no successful synthesis of magnesium alanate has been achieved by MCS of the nanostructured magnesium alanate using four starting stoichiometric Mg-2Al mixtures. It is hypothesized that Al(Mg) solid solution in the initial stage (~10h) of CRMA and free Al(s) decomposed from solid solution as the milling time increases the initial stage inhibit the reaction to form magnesium alanate. In contrast to an unsuccessful synthesis in MCS process, a successful synthesis of the magnesium alanate and 2NaCl mixture by MCAS has been achieved. DSC and TGA analysis show that the decomposition of magnesium alanate occurs in a two-step reaction at the temperature ranges of 125-180 and 225-340°C. In the Mg-B-H system, when the Mg-2B mixture is made with the oxidized amorphous boron containing B2O3 then after a prolonged MCS time (200h), only nanometric γ- and β- magnesium hydrides are formed. In contrast, oxide-free amorphous boron in the original Mg-2B mixture prompts the formation of a resulting mixture of nanometric MgB2 and an amorphous phase containing hydrogen. Further annealing of the milled Mg-2B mixtures at ~100-400ºC under ~4-4.3 MPa of hydrogen for 20-100h does not result in the formation of ternary magnesium alanate. Alternatively, a powder mixture of 2NaBH4 and MgCl2 is used as a starting material to synthesize Mg(BH4)2 hydride. Amorphous Mg(BH4)2 phase might have been synthesized after MCAS process. However, the formation of Na(Mg)BH4 solid solution might prevent the synthesis of a large amount of Mg(BH4)2 hydride. Once the solid solution is formed, the amount of Mg will be insufficient to form a large amount of Mg(BH4)2 hydride.

The present work reports a study of mechano-chemical synthesis (MCS) and mechano-chemical activation synthesis (MCAS) of nanostructured hydrides in the Mg-H, Mg-Al-H and Mg-B-H systems by controlled reactive mechanical alloying/milling (CRMA/CRMM) in the magneto-mill Uni-Ball-Mill 5. Regardless of the hydride systems, the morphologies of milled Mg-H, Mg-Al-H and Mg-B-H powders after a prolonged milling time can be characterized by dramatic particle size refinement and high tendency to form agglomerates. In the Mg-Al-H system, no successful synthesis of magnesium alanate has been achieved by MCS of the nanostructured magnesium alanate using four starting stoichiometric Mg-2Al mixtures. It is hypothesized that Al(Mg) solid solution in the initial stage (~10h) of CRMA and free Al(s) decomposed from solid solution as the milling time increases the initial stage inhibit the reaction to form magnesium alanate. In contrast to an unsuccessful synthesis in MCS process, a successful synthesis of the magnesium alanate and 2NaCl mixture by MCAS has been achieved. DSC and TGA analysis show that the decomposition of magnesium alanate occurs in a two-step reaction at the temperature ranges of 125-180 and 225-340°C. In the Mg-B-H system, when the Mg-2B mixture is made with the oxidized amorphous boron containing B2O3 then after a prolonged MCS time (200h), only nanometric γ- and β- magnesium hydrides are formed. In contrast, oxide-free amorphous boron in the original Mg-2B mixture prompts the formation of a resulting mixture of nanometric MgB2 and an amorphous phase containing hydrogen. Further annealing of the milled Mg-2B mixtures at ~100-400ºC under ~4-4.3 MPa of hydrogen for 20-100h does not result in the formation of ternary magnesium alanate. Alternatively, a powder mixture of 2NaBH4 and MgCl2 is used as a starting material to synthesize Mg(BH4)2 hydride. Amorphous Mg(BH4)2 phase might have been synthesized after MCAS process. However, the formation of Na(Mg)BH4 solid solution might prevent the synthesis of a large amount of Mg(BH4)2 hydride. Once the solid solution is formed, the amount of Mg will be insufficient to form a large amount of Mg(BH4)2 hydride.

<p>Processing of nanostructured WC-Co and W-Co powders,modelling of Fe-Mn-Si alloy, swelling of Fe-Cu alloy, andmechanical properties and sintering of Fe-Mn-Si steels havebeen studied in the present thesis.</p><p>W-Co precursors made by chemical synthesis were used toproduce nanostructured WCCo and W-Co powders by calcination,reduction and carburization. The phase constituents in thecalcined powders depend on temperature and atmospheres. Cobaltcan accelerate the reduction rate of the W-Co precursors as acatalyst, and cobalt influences the formation of intermediatephases during the reduction of the precursors.</p><p>The ratio of carbon monoxide to carbon dioxide controlscarburization process, gives different intermediate phases andcarburization rates. There exist several intermediate phases: W₆Co₆C, W₃Co₃C, W₂C due to varying carbon monoxide content in thecarburization gases. Nanostructured WC-Co powders with aparticle size of 20-50 nm have been obtained.</p><p>The effect of silicon content on the particle sizedistribution of milled Fe-Mn-Si master alloy powders is muchmore significant than that of manganese content. A finer finalparticle size can be obtained in the alloy powders with highersilicon compositions. Long time milling results in theagglomeration of small particles. The grinding process can bedescribed using classic batch grinding equation based on thepopulation balance model. A swelling model for Fe-Cu alloyssintered at the temperatures above the melting point of copperhas been established based on the penetration mechanism. In themodel, the particle coordination number and heating rate wereused to express the porosity and the thickness of the diffusionlayers between iron and copper particles respectively.</p><p>The effects of sintering temperature and time on theproperties of sintered steels have been studied. Fe-Mn-Simaster alloys made by cast-milling, atomizing, and acombination of atomization and milling have been covered. Themilled, and atomizationmilled alloy steels showed goodmechanical properties with small dimensional change. Transientliquid phase of the Fe-Mn-Si alloys accelerates densification,and offer fast diffusion of alloying elements. The addition ofa small amount of Fe-Mn-Si master alloy to Astaloy 85Mo powdercan lead to high strength with zero dimensional change.</p><p><b>Key words:</b>Processing; Modelling; Nanostructured powder;WC-Co; W-Co; Calcination; Reduction; Carburization; Particlesize; Sintered steel; Fe-Cu alloy; Swelling; Fe-Mn-Si masteralloy; Mechanical properties; Sintering parameters.</p>

La bioactivité des chitooligosaccharides semble dépendre des degrés de Nacétylation et de polymérisation ainsi que de la distribution des unités répétitives D-glucosamine et N-acétyl-D-glucosamine. Afin de préparer des structures parfaitement définies, nous avons développé une nouvelle méthode basée sur la synthèse chimique totale d’oligosaccharides pouvant être décrite en trois étapes :1- préparation de quatre monosaccharides jouant le rôle de donneurs et accepteurs de GlcN et GlcNAc2- formation des oligosaccharides protégés suite à la réaction de couplage d’un donneur de GlcN/GlcNAc avec un accepteur de GlcN/GlcNAc3- suppression des groupes protecteurs permettant l’obtention des chitooligosaccharides cibles.Un avantage important de cette stratégie vient de sa convergence. Ainsi, chaque structure protégée de chitooligosaccharide peut être convertie en un nouveau donneur ou accepteur de glycosyle par modification chimique, conduisant ensuite aux chitooligosaccharides de plus haut DP. / Bioactivity of chitooligosaccharides seems to depend on their degrees of Nacetylationand polymerisation but also the sequence of the D-glucosamine and Nacetyl-D-glucosamine units. To prepare well defined structures, we have developeda new method based on the total chemical synthesis of oligosaccharides describedin three stages:1- preparation of four monosaccharides playing the role of donors and acceptors ofboth GlcN and GlcNAc2- formation of protected oligosaccharides by the coupling reaction of oneGlcN/GlcNAc donor with one GlcN/GlcNAc acceptor3- removal of protecting groups to generate targeted chitooligosaccharidesAn important advantage of this strategy is based on its convergence. Thus, eachprotected chitooligosaccharide structure can be converted into a new glycosyldonor or acceptor, thanks to chemical modifications, and then leads to higher DPchitooligosaccharides

Some compounds, analogous to those found in naturally occurring systems, are found to possess chemotherapeutic activity. Some, in the form of their nucleoside or nucleotide derivatives, are valuable antimetabolites in that they may block normal RNA or DNA polymerisation, or may be incorporated into nucleic acids to form fraudulent, but not necessarily defective, polymers. Modification of natural ring systems, with a view to promoting chemotherapeutic activity is therefore of considerable interest; variation in the position and nature of the modification or ring substituent having a marked effect on chemotherapeutic activity. It is the purpose of this thesis to suggest methods for the facile synthesis of various uracils, pyrazoles and pyrazolo [3,4-d] - pyrimidines with alkyl, aryl and glycosyl substituents such that the nature of the ring substituents is easily varied. To this end a number of ethoxymethylene reagents were prepared which, by reaction with primary amines and hydrazines, would give acyclic intermediates capable of easy cyclisation into the uracil, pyrazole and pyrazolo [3,4-d] pyrimidine ring systems. Variation in the nature of specific substituents being determined by the choice of amine or hydrazine, other substituents being varied by modification of the original reagent.