Improved Methodology for the Preparation of Chiral Amines

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EtO 2 C H H CO 2 Et R O H + H 2 N OMe N H S (1.1 equiv) R N H OMe H 2 N NH 2 (1.0 equiv) 5 Å MS, toluene, 70 °C Scheme 3.22. Reductive Amination of Aldehydes Utilizing Thiourea. One of the milestones in this field was developed by MacMillan, who investigated the reductive amination of acetophenone with p-anisidine utilizing ethyl Hantzsch ester, and BINOL-derived phosphoric acids. The catalyst showed high catalytic activity and excellent enantiocontrol in the reductive coupling reaction. Removal of water by the addition of 5Å molecular sieves proved to be important for achieving high catalytic activity and selectivity. Aryl-alkyl ketones were reduced with good yields (70-87%) and high enantioselectivity (85- 97%) and 2-alkanones were also reduced with mediocre to good yields (49-75%) with good to high enantioselectivities (81-94%). Different aniline derivatives were tested producing the secondary amine with good to high yields (55-92%) and high enantioselectivities (90-95%). The overall diversity of ketone substrates makes his work fascinating from all aspects. [64] O 15 (10 mol%),PMPNH 2 (1 equiv), MS 5A,C 6 H 6 ,50 o C, 96h, 87% HN PMP EtOOC COOEt N H (1.2 equiv) 87% yield, 94 % ee SiPh 3 O O P O OH 15 SiPh 3 OMe OMe OMe HN F HN F HN 79 % yield, 91 % ee 60 % yield, 83 % ee 72
OMe OMe O HN HN HN O 2 N 71 % yield, 95 % ee 75 % yield, 85 % ee 92 % yield, 91 % ee HN OMe HN OMe HN OMe 71 % yield, 83 % ee 2 60 % yield, 90 % ee 73 % yield, 96 % ee Scheme 3.23. Asymmetric Reductive Amination System Developed by MacMillan 3.4. Green Chemistry and Reductive Amination: 3.4.1. Green Chemistry Basic principles. Reductive amination is a one pot process for chiral amine synthesis. As described previously, it has many advantages compared to the other available methodologies. One of the significant advantages of this methodology is that it is considered an environmentally friendly process. To understand on which bases scientists made such assumption, we have first to know more about green chemistry and environmentally friendly process. It is widely acknowledged that there is a growing need for more environmentally acceptable processes in the chemical industry and pharmaceutical industry. This trend has led to the concept of ‘Green Chemistry’. [65] The new trend differs dramatically from the old traditional concepts focused only on process efficiency and chemical yield. The new trend assigns the economic value of the process depending on its ability to eliminate waste at source and avoid the use of toxic and/or 73
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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.
Page 35 and 36: (S)-(α)-Methylbenzylamine and its
Page 37 and 38: fourth chapter showing different dr
Page 39 and 40: Burk was successful in reducing ary
Page 41 and 42: Table 1.1 Rhodium Catalyzed Reducti
Page 43 and 44: [8] E. L. Eliel, S. H. Wilen, Stere
Page 45 and 46: [42] a) J. Blacker, Innovations in
Page 47 and 48: [67] a) H. Qin, N. Yamagiwa, S. Mat
Page 49 and 50: of imine reduction in the past eigh
Page 51 and 52: 8 years beginning from the year 200
Page 53 and 54: 2.2.3. Nguyen Special Substrates. A
Page 55 and 56: Figure 2.4 General Catalyst structu
Page 57 and 58: 2.3.2. Different Substrates Categor
Page 59 and 60: H 2 , toluene, 25 °C, 4 h an ee of
Page 61 and 62: 1). They described the role of each
Page 63 and 64: 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
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Page 85: Later he utilized this methodology
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 and 116: The unique feature of this methodol
Page 117 and 118: Ytterbium triflate is the most comm
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
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e.g. compare entries 1, 5, 6, and 9
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solvent in the stoichiometric and c
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[2] Farina, V.; Grozinger, K.; Mül
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congested which should be favored.
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imine area % (GC analysis) time (mi
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Inversion at the nitrogen atom of t
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anti-6) would be expected to have m
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e.g. AcOH, suppresses alcohol by-pr
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eductive amination of a prochiral k
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Appendix Experimental Section Gener
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and the mixture was stirred for 30
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Reaction details: Yb(OAc) 3 (1.1 eq
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etention time [min]: major (S,S)-2b
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time [min]: major (S,S)-2c isomer,
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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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Improved Methodology for the Preparation of Chiral Amines

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