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Journals and Conferences
Multilevel inverter have been attracting increasing interest recently due to the increased power rating, improving harmonic performance, and reduced electromagnetic inference (EMI) emission. A voltage source inverter is commonly used to supply a variable frequency variable voltage to a three phase induction motor in a variable speed application. The output… (More)
Reaction of cyclic secondary amines with 1-alkynes and copper(I) chloride at 110-120 °C gives the corresponding alkynylcopper complex, which adds to the iminium ion intermediate formed in situ by hydroamination of 1-alkynes to give the corresponding propargylamine derivatives in up to 94% yield and 99% regioselectivity. The diastereomerically pure chiral… (More)
Copper bromide promoted reactions of aldehydes, 1-alkynes, and chiral 2-dialkylaminomethylpyrrolidine at 25 °C give the corresponding chiral propargylamine derivatives in up to 96% yield and 99:1 dr that are readily converted to the corresponding disubstitued chiral allenes in up to 81% yield and 99% ee upon reaction with CuI in dioxane at 100 °C.
[reaction: see text] A new method of achieving homogeneity of chirality via purification of nonracemic (partially resolved) amino alcohols 1a-d and the C2 chiral diamine 2 to obtain samples of higher ee, through preparation of homochiral and heterochiral aggregates using oxalic and fumaric acids, is described.
Chiral allenes are readily accessed in a single pot operation in the reaction of terminal alkynes, aldehydes, chiral secondary amines, and zinc halides in good yields (up to 77% yield) and excellent enantioselectivities (up to 99% ee) in toluene at 120 °C. The reaction proceeds through initial formation of chiral propargylamine intermediates with creation… (More)
In today’s world, the leading industries are very much concerned about reducing down-time and increasing the productivity as well as the quality. To increase the product quality, the tool should have good performance. Drilling process is widely used in the manufacturing operations in all the manufacturing industries. In this study, two Hidden Markov Models… (More)
Racemic 2,3-diaryl-1,4-diazabicyclo[2.2.2]octane (DABCO) derivatives are synthesized from the readily accessible piperazines in 50-64% yield by cyclization using ethylene bromide, triethylamine, and KI at 80 °C. The enantiomerically enriched 2,3-diphenylpiperazine and the 2,3-bis(1-naphthyl)piperazine derivatives are prepared by a resolution method using… (More)
l. INTRODUCTION 1.1 In radio astronomy it is often necessary to display brightness distribution map of the sky with Right Ascension and declination as its coordinates. When the graphic technique is used for the above astrophysical interest, the methods chosen to present the data in pictorial form should have an important effect on the speed and efficacy… (More)
Partial resolution of racemic 1,1'-bi-2-naphthol (1) was readily achieved to obtain enriched (scalemic) 1 using (S)-proline (2). The structure of the complex 3 formed between 1 (2 equiv) and (S)-proline (1 equiv) was characterized by an X-ray diffraction method. Enantiomeric excesses of the incompletely resolved 1 were enriched to obtain essentially pure… (More)
Carbon materials like activated carbon (AC) undergo chemisorption with O2 to give species with electron deficiency in the carbon skeleton and negative charge at the oxygen end that upon reaction with PPh3 and benzoic acid afford Ph3P═O. Whereas amine donors react with O2-chemisorbed AC and nucleophiles to give dehydrogenatively coupled products in 67-89%… (More)