Improved Methodology for the Preparation of Chiral Amines

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longest-lived radioisotope Yb-169, t1/2 32.03 days; shortest-lived radioisotope Yb-154, 0.40 second. 5.1.1.2. Ytterbium Discovery: Ytterbium was discovered in 1878 by J. C. G. de Marignac. The element got its name from the Swedish village Ytterby where this rare earth first was discovered. In 1907, Urbain separated ytterbia into two components, neoytterbia (oxides of ytterbium) and lutecia (lutecium). The first preparation of metallic ytterbium was achieved by Klemm and Bommer through reduction with potassium metal resulting in an impure ytterbium metal (mixed with potassium chloride). Daane, Dennison, and Spedding were the first to prepare the pure metal in 1953 in gram quantities. Abundance of ytterbium in the earth’s crust is estimated to be 3.2 mg/kg. Up till now the metal had showed very little applications on the commercial level. In elemental form it can be used as a laser source, a portable x-ray source, and as a dopant in garnets. When added to stainless steel, it improves grain refinement, strength, and other properties. Some other applications, particularly used as oxides mixed with other rare earths, include carbon rods for industrial lighting, in insulated capacitor and in glass industry. Its radioactive isoptope is used in detection of metal perfection. 5.1.1.3. Ytterbium Reactions: Ytterbium metal reacts with oxygen above 200°C forming two oxides, the monoxide, YbO, and more stable sesquioxide, Yb 2 O 3 . The metal dissolves in dilute and concentrated mineral acids. At ordinary temperatures, ytterbium, similar to other rare earth metals, is corroded slowly by caustic alkalies, ammonium hydroxide, and sodium nitrate solutions. The metal dissolves in liquid ammonia forming a deep blue solution. It can react slowly with halogens at room temperature but progress rapidly above 200°C forming ytterbium trihalides. All the trihalides; namely, the YbCl 3 , YbBr 3 , and YbI 3 with the exception of trifluoride, YbF 3 , are hygroscopic and soluble in water. Ytterbium forms many binary, metalloid, and intermetallic compounds with a number of elements when heated at elevated temperatures. It can form salt with organic acid triflic or acetic acid. These salts and the salts with halogens are used as Lewis acids in different organic transformations. [6] 102
Ytterbium triflate is the most commonly used form of ytterbium in organic synthesis. It is used in Michael addition of β-Ketoester in water, [7] synthesis of ethyl arylacetates, [8] hydrolysis of tritylamines and trityloxy compounds to the corresponding amines and alcohols, [9] electrophilic substitution of indoles for the synthesis of unnatural tryptophan derivatives, [10] Friedel–Crafts reaction of arylidenecyclopropanes, [11] synthesis of polyhydroquinoline derivatives, [12] and synthesis of substituted imidazoles. [13] 5.1.1.4. Ytterbium Acetate Ytterbium acetate is a moderately water soluble crystalline ytterbium source that decomposes to ytterbium oxide on heating. Acetates are excellent precursors for the production of ultra high purity compounds and certain catalysts and nanoscale (nanoparticles and nanopowders) materials. All metallic acetates are inorganic salts of a metal cation and the acetate anion. The acetate anion is a univalent (-1 charge) polyatomic ion composed of two carbon atoms ionically bound to three hydrogen and two oxygen atoms (Symbol: CH 3 COO) for a total formula weight of 59.05. Ytterbium acetate is applied to fibre amplifier and fibre optic technologies and in lasing applications. It has a single dominant absorption band at 985 in the infra-red useful in silicon photocells to convert radiant energy to electricity. Two examples were reported in literatures for the applications of ytterbium acetate in organic chemistry. Fujiwara reported the use of ytterbium acetate for the synthesis of acetic acid in water. The method depends on the carboxylation of methane with carbon monoxide using ytterbium acetate. Sodium hypochlorite or hydrogen peroxide was used as the oxidant in this reaction. The catalytic activity was improved by the addition of transition-metal salts such as manganese acetate. The best result was achieved at a ratio of manganese acetate to ytterbium acetate of 1:10. [14] Oshima reported the use of ytterbium acetate as additive in oxidation of alcohols to aldehydes and ketones utilizing iodosylbenzene as oxidant. Mixing ytterbium salt with isodosylbenzene and alcohol in 1,2-dichloroethane and heating the mixture at 80 °C for 3.5 hours provided the ketone products in good to excellent yields. [15] 103
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Improved Methodology for the Prepar
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This dissertation is dedicated to a
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suppressing alcohol formation and p
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Prof. Mohamed El-Azizi, Prof. Abdel
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Et EtOH EtOAc GC h HPLC HRMS Hz J K
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Table of Contents Abstract. Acknowl
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4.1.5. Synthesis of Emitine 85 4.1.
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Chapter 1 Introduction 1.1. Chiral
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1. Cis-trans or geometric isomers.
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O O O * NH Thalidomide (R)-active a
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One enantiomer may be responsible f
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1.5.1. Synthesis of Enantiomericall
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1.5.2.2. Kinetic Resolution Kinetic
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compound by the auxiliary. The auxi
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1.5.4. Stereoselective Conversion o
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It is estimated that 3000 tonnes (a
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k R R P 1 k rac S k S P 2 Figure 1.
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(S)-(α)-Methylbenzylamine and its
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fourth chapter showing different dr
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Burk was successful in reducing ary
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Table 1.1 Rhodium Catalyzed Reducti
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[8] E. L. Eliel, S. H. Wilen, Stere
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[42] a) J. Blacker, Innovations in
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[67] a) H. Qin, N. Yamagiwa, S. Mat
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of imine reduction in the past eigh
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8 years beginning from the year 200
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2.2.3. Nguyen Special Substrates. A
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Figure 2.4 General Catalyst structu
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2.3.2. Different Substrates Categor
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H 2 , toluene, 25 °C, 4 h an ee of
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1). They described the role of each
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More recently, 2008, he described t
Page 65 and 66: [22] E. Guiu, M. Aghmiz, Y. Diaz, C
Page 67 and 68: Chapter 3 Reductive Amination 3.1.
Page 69 and 70: . CH 3 CO(CH 2 ) 5 CH 3 H 2 NCH 2 C
Page 71 and 72: superior in terms of conversion (89
Page 73 and 74: O NHR 3 R 4 R 4 R 3 N OTi(O i Pr) 3
Page 75 and 76: Scheme 3.9. Synthesis of (S)-Metola
Page 77 and 78: groups decreased both the enantiose
Page 79 and 80: progress of the reaction was monito
Page 81 and 82: attempts were directed for the asym
Page 83 and 84: hydrogen bonding, is chiral and its
Page 85 and 86: Later he utilized this methodology
Page 87 and 88: OMe OMe O HN HN HN O 2 N 71 % yield
Page 89 and 90: compared to the oil refinery indust
Page 91 and 92: [14] V. I. Tararov, R. Kadyrov, T.H
Page 93 and 94: [55] a) R. Kadyrov, T. H. Riermeier
Page 95 and 96: Chapter 4 Drugs and Reductive Amina
Page 97 and 98: Scheme 4.2. Synthesis of Muraglitaz
Page 99 and 100: Studies showed that the active isom
Page 101 and 102: aminoacid producing the protected a
Page 103 and 104: O NH 2 1. p-TsOH/toluene 2. BH 3 -T
Page 105 and 106: O O 125 NH 2 a 93% O O 126 H Bu N T
Page 107 and 108: ethyl carbamate by acylation with e
Page 109 and 110: 4.1.16. Synthesis of Ritonavir and
Page 111 and 112: 4.2. Conclusion Different important
Page 113 and 114: Chapter 5 Stoichiometric Use of Ytt
Page 115: The unique feature of this methodol
Page 119 and 120: Ruthenium(III) chloride 31.7 4 4.2
Page 121 and 122: t-Butyl methyl ether 15 - - 82 Hexa
Page 123 and 124: 2-octanone starting material. When
Page 125 and 126: 3 Yb(OTf) 3 d 4 Ti(O i Pr) 4 e 5 B(
Page 127 and 128: If a [1,3]-proton shift of the init
Page 129 and 130: enhanced stereoselectivity. For exa
Page 131 and 132: WO2006030017, 2006; c) T. C. Nugent
Page 133 and 134: 4 60 86 5 50 86 6 40 84 7 20 79 8 2
Page 135 and 136: The reactions described above all u
Page 137 and 138: e.g. compare entries 1, 5, 6, and 9
Page 139 and 140: solvent in the stoichiometric and c
Page 141 and 142: [2] Farina, V.; Grozinger, K.; Mül
Page 143 and 144: congested which should be favored.
Page 145 and 146: imine area % (GC analysis) time (mi
Page 147 and 148: Inversion at the nitrogen atom of t
Page 149 and 150: anti-6) would be expected to have m
Page 151 and 152: e.g. AcOH, suppresses alcohol by-pr
Page 153 and 154: eductive amination of a prochiral k
Page 155 and 156: Appendix Experimental Section Gener
Page 157 and 158: and the mixture was stirred for 30
Page 159 and 160: Reaction details: Yb(OAc) 3 (1.1 eq
Page 161 and 162: etention time [min]: major (S,S)-2b
Page 163 and 164: time [min]: major (S,S)-2c isomer,
Page 165 and 166: obtain the hydrochloride salt (0.41
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with etheral HCl provided the hydro
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Research experience: Date Project S
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