Browsing by Author "Özer, MS"

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    Asymmetric synthesis of (S)-dihydrokavain from l-malic acid
    Eskici, M; Karanfil, A; Özer, MS; Kabak, Y; Durucasu, I
    A practical and efficient asymmetric synthesis of (S)-dihydrokavain from known ethyl (S)-2-hydroxy-4-phenylbutanoate which is, in turn, readily available from l-malic acid as a cheap chiral pool material is described using regioselective ring-opening of the 1,2-cyclic sulfate with lithium-3,3,3-triethoxypropiolate and subsequent HgO/H2SO4-mediated lactonization as the key steps. Its opposite enantiomer (R)-dihydrokavain was also synthesized from d-malic acid using the same sequences of reactions for the purpose of optical purity determination. [GRAPHICS] .
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    Reactivity of cyclic sulfamidates towards lithium acetylides: synthesis of alkynylated amines
    Eskici, M; Karanfil, A; Özer, MS; Sarikürkcü, C
    A synthetically useful level of reactivity of cyclic sulfamidates toward acetylides is described. Ring-opening reactions of a structurally diverse set of 1,2- and 1,3-cyclic sulfamidates with a range of lithium acetylides from aliphatic, cyclic, aromatic, heteroaromatic, and functionalized alkynes proceed smoothly in a regioselective manner to give the corresponding N-sulfate intermediates. Hydrolysis of these intermediates under acidic conditions furnishes the alkynylated amines in yields ranging from 29% to 98%. The scope of the acetylenic substitution reaction with the structural variations in both the cyclic sulfamidates and alkynes is briefly examined. (C) 2011 Elsevier Ltd. All rights reserved.
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    Study on lubricant quality and its effect on engine component performance
    Besergil, B; Özer, MS; Eskici, M; Atik, E
    Purpose - This paper aims to determine the usage time of the test lubricant NO, prepared from base oils of Aliaga Plant, Izmir, in gasoline and diesel-engines, and the investigations of high-temperature oxidation, engine-protective properties, and property changes of the lubricant in performance time. Design/methodology/approach - Physical and chemical properties of the lubricating oil were initially established, and the oil was then subjected to Petter W-1 gasoline and Petter AV-1 diesel test engines. Dismantling of the engine parts was followed by the examination of pistons, piston rings and bearings, and analysis of the lubricant was also undertaken. The engine performance test results and the quality control of the lubricating oil assessments were evaluated according to the International Engine Lubricant Specifications. Findings - The lubricating oil, under sluggish experimental conditions, appears to meet a 40-hour test in gasoline engines and a 120-hour test in diesel engines with the specifications. This means that under usual working conditions the lubricants keep the engine protective properties in 7,000 km distance for gasoline run-vehicles, and in 5,000 km distance for diesel run-vehicles, after which change of the oil is required. Originality/value - The paper provides information of value to those involved with lubrication and engine performance.