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  • 1
    Electronic Resource
    Electronic Resource
    α,β-Unsaturated nitriles in heterocyclic synthesis: Synthesis of some new pyrazolo[1,5-a]pyrimidine derivatives (1984)
    Springer
    Monatshefte für Chemie 115 (1984), S. 1413-1419 
    Details
    ISSN: 1434-4475
    Keywords: Cinnamonitriles ; Cyanoethylations ; Heterocycles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung 3-Antipyrinyl-5-aminopyrazol (1) reagierte mit Acrylnitril zu 5-Amino-1-β-cyanoethyl-3-antipyrinylpyrazol (2).2 konnte ebenfalls aus der Reaktion von β-Cyanethylhydrazin (3) und Verbindung4 erhalten werden.2 wurde mittels Essigsäure-Salzsäure glatt zu 2-Antipyrinyl-4,5,6,7-tetrahydropyrazolo[1,5-a]-pyrimidin-5-on (5) cyclisiert.5 konnte auch aus der Reaktion von1 mit Methylacrylat erhalten werden. Die Reaktion von1 mit Zimtsäurenitrilderivaten7 a–e ergab die Pyrazolo[1,5-a]pyrimidin-Derivate9,11 und12.
    Notes: Abstract 3-Antipyrinyl-5-aminopyrazole (1) reacted with acrylonitrile to afford 5-amino-1-β-cyanoethyl-3-antipyrinylpyrazole (2). Compound2 could also be obtained from the reaction of β-cyanoethylhydrazine (3) and compound4.2 was readily cyclized into 2-antipyrinyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidin-5-one (5) by acetic-hydrochloric acid.5 could be also obtained from the reaction of1 and methyl acrylate. The reaction of1 and cinnamonitrile derivatives7 a–e resulted in the formation of pyrazolo[1,5-a]pyrimidine derivatives9,11 and12.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00816340
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  • 2
    Electronic Resource
    Electronic Resource
    Differential availability of partially sulphuric and phosphoric acidulated phosphate rocks I. Plant response (1996)
    Springer
    Nutrient cycling in agroecosystems 47 (1996), S. 251-259 
    Details
    ISSN: 1573-0867
    Keywords: Partially acidulated phosphate rock ; residual PR ; P uptake ; soil pH ; agronomic effectiveness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A glasshouse study was conducted to determine the influence of soil pH on the agronomic effectiveness of partially phosphoric (Phos-PAPR) and partially sulphuric (SA-PAPR) acidulated phosphate rocks (PR). For Phos-PAPR ground North Carolina PR (NCPR) was acidulated with 10, 30 and 50% of acid needed for complete acidulation. For SA-PAPR a blend of NCPR, Arad and Khouribga PRs were acidulated with 60% of the acid needed. The relative agronomic effectiveness of these PAPRs were compared with superphosphate (SSP) and ground NCPR. A highly phosphate (P) retentive and P deficient pasture soil was used. Prior to addition of fertilizers to soil, the pH of soil was adjusted to 5.1 (initial soil pH) 5.4, 5.7 and 6.1 by applying varying amounts of Ca(OH)2. Ryegrass (Lolium perenne) was grown as the test plant over a period of eight months. Fertilizers were applied at three rates plus control. Soil pH was monitored and continuously adjusted to the desired levels throughout the experimental period. The dry matter yields and P uptake in SSP treated pots were not influenced by soil pH. With increasing soil pH, agronomic performance of Phos-PAPRs and NCPR significantly (P〈0.01) decreased but that of SA-PAPR was not affected. On the basis of per unit water-soluble P applied, uptake of P by plants was greater from PAPRs than SSP. Using the P uptake values of SSP and NCPR (which was used to prepare the PAPRs), the dissolution of P from the residual PR component of the PAPRs were calculated. The residual PR component of the Phos-PAPRs apparently dissolved in greater quantities than unacidulated NCPR. Dissolution of the residual PR was enhanced with increasing degree of acidulation. However, in the case of SA-PAPR, the agronomic performance of the PAPR was mostly dependent on the water-soluble P component of the PAPR. The uptake of P from the residual PR component of the SA-PAPR was insignificant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01986280
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  • 3
    Electronic Resource
    Electronic Resource
    Differential influence of soil pH on the availability of partially sulphuric and phosphoric acidulated phosphate rocks II. Chemical and scanning elecronmicroscopic studies (1997)
    Springer
    Nutrient cycling in agroecosystems 48 (1997), S. 171-178 
    Details
    ISSN: 1573-0867
    Keywords: Calcium sulphate ; partially acidulated phosphate rock ; soil pH ; solubility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Part I of this study showed that the plant availability of P from a reactive phosphate rock (PR), North Carolina PR, partially acidulated with phosphoric acid (Phos-PAPR) increased with decreasing soil pH from pH 6.1 to 5.1, whereas availability from a blend of similarly reactive PRs partially acidulated with sulphuric acid (SA-PAPR) changed little. The present study was carried out to explain the above results. Phosphate sorption maximum of soil as a function of soil pH was determined. Soil samples obtained at the completion of the pot experiment [5] were analysed for inorganic P fractions, and the amounts of PR dissolved from the PAPRs were determined. A leaching study, simulating pot experiment conditions, was conducted to determine the changes in the chemical composition and the spatial distribution of P, S and Ca in the fertilizer residues. The properties of the PAPRs were further characterised by sequential extraction of the fertilizers. Phosphate sorption isotherms indicated a smaller amount of P in solution at lower pH values, which suggested reduced P availability with decreasing soil pH. Dissolution of the residual PR-P was generally greater in Phos-PAPR treatment than in PR applied directly or in the SA-PAPR treatment. PR-P dissolution in Phos-PAPR increased with decreasing pH but not in SA-PAPR. Chemical, electron microprobe, X-ray micro-analysis and X-ray powder diffraction studies of the fertilizer residues obtained from the leaching and sequential extraction experiments showed rapid dissolution of the Ca(H2PO4)2 phase of the fertilizers but the CaSO4.XH2O persisting as a cementing phase between the PR particles. The CaSO4.XH2O which intially existed mostly in an anhydrous form changed to gypsum. It was concluded that the dissolution of PR-P in the SA-PAPR was impeded by the presence of CaSO4.XH2O acting as a physical barrier and also by providing higher Ca in solution than that would exist in a saturated solution of the apatites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009736623302
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    Paper (German National Licenses)
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