Solution and Solid Phase Synthesis of Unusual a-Amino Acids From

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1.53 was also successhrlly methylenylated with AIMemCH212 in 75% yield with >95% ee (Scheme 3.16)." The amino alcohol 3.34 was not oxidized to the amino acid since it was shown to proceed in low yield. CHO Scheme 3.16 7 L-vinylglycine has been synthesized fiom L-homoserine 3.35 in 49% overall yield (Scheme 3.17)& and L-homoserine lactone 3.36 (Scheme 3.18)" in 72% overall yield with both routes involving dehydroselenoclirninations. L-Homoserine and its lactone are readily available in both enantiomeric forms. Scheme 3.17 Scheme 3.18
L-vinylglycine has also been synthesized using methodology previously developed in our laboratory. Cbz-Ser(a1d)-OB0 ester 3.37 was reacted with methylenetriphenyl-phosphorane to give the vinylglycine intermediate 3.m which was then deprotected to give vinylglycine in 5 1% yield over 3 steps albeit in 77% ee? Scheme 3.19 3.1.4 Synthesis of Labelled fl ~Unsaturated Amino Acids A major disadvantage of many of the methods developed for the synthesis of vinylglycines, especially those that rely on degradation of an amino acid, is that isotopic label incorporation is mcult. Two synthesis leading to racemic products have been described. Chang and Walsh1= prepared (z)-[~-~H], (E)-[~-~H] and (~)-[3,4-~~~]vin~l~l~cine for mechanistic studies by catalytic hydrogenation of aikyne intermediates. Sa~ada~~ and CO-workers prepared (~)-[3,4-~~z], (2)-13 ,4-2~t], (E)-[~-~H] and [3 ,4,4-2~3]-vinylg~ycine via a stereoselective reduction of phenyl-2-(TMS)-ethynyl sulfone. 3.2 Results and Discussion: Synthesis of Vinylglycine from Serine Given that the synthesis of vinylglycine 3.7 via Wittig olefination of Fmoc- Ser(a1d)OBO resulted in partial racernization (77% ee) and very poor yields due to Fmoc cleavage,' we hypothesized that the basic ylide was responsible for both the racernization
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Solution and Solid Phase Synthesis
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The University of Waterloo requires
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Many people have made the experienc
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Table of Contents Abstract ........
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23 Summary ........................
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5.1.4.1 Enzymatic Methods .........
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List of Tables Table 2.1 Table 2.2
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Figure 4.1 O Figure 5.1 Figure 5.2
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CYS d DAST DBAD DBU DCC de DEAD dec
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NMP Nu OB0 ester PEG Ph Phe PhFl Ph
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1.1 General Introduction Chapter On
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acids will be presented including a
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.J generation of the enolate and ad
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classical techniques (Scheme 1.7) a
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s~ccess.~ The same principle has be
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O Scheme 1.11 O R1,qH2 m OH RI= H,
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stereosele~tivities.~ Numerous exam
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Williams and coworlcers have examin
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template, reaction with alkyl halid
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The 3-bromo analog of Williams and
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formation of serine aldehydes; dire
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Scheme 1.24 R dimethoxy- R ProPane
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of thiol trityl led to racemic cyst
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nucleophiles such as acetate and im
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may be employed, while the oxidatio
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Several methods for the removal of
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1.5 References Barrett, G.C. Chemis
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(a) Schmidt, U.; Meyer, R.; Leitenb
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R.M. Tetrahedron Le#. 2001,42, 769.
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(a) Lubell, W.D.; Rapport, H. J. Am
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Nakajima, K.; Takai, F.; Tanaka, T.
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2.1 Introduction Chapter Two Synthe
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2.1.1 Synthesis of SHydroxy-a-Amino
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typically generated in both poor yi
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2.1.3.3 Electrophilic%Nucfeophilic
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Scheme 2.8 2-(Arylthi0)-2-nitrooxir
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Scheme 2.10 Schollkopf et al. have
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2.1.3.5 Synthesis fiom #-Amino Acid
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HO Scheme 2.17 This laboratory prev
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Scheme 2.19 NaBr, acetone The best
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equires carefiil attention to preve
Page 83 and 84: order to investigate this as a poss
Page 85 and 86: etained its optical activity indica
Page 87 and 88: 2.2.3.2 Ortho Ester Cleavage Concom
Page 89 and 90: 2.2.4 Determination of Enantiomeric
Page 91 and 92: minof si face aîîack mior re face
Page 93 and 94: 2.4.1 General Methods. Most reagent
Page 95 and 96: The crude product was fiitered thro
Page 97 and 98: 250 MHz) 6 5.47 (br ci, lH, J = S.O
Page 99 and 100: evaporated to dryness. The residue
Page 101 and 102: minutes. The akohol solution was tr
Page 103 and 104: 302.1604, found 302.1593; Anai. cal
Page 105 and 106: CCH3), 28.3 (a3)C), 20.1 (fLm3) 13.
Page 107 and 108: TLC (4: 1, CH2C12:EtOAc) Rf = 0.44;
Page 109 and 110: 100-200 mesh, hydrogen form, 1x10 c
Page 111 and 112: (br d. IH. J= 10.6Hz, CHH-CH), 4.63
Page 113 and 114: mp 80-8 1 OC; [a~~*~a= -67.0 (0 1.5
Page 115 and 116: esin column (Bio-Rad AGa 10x4 10-20
Page 117 and 118: Jung, M.E.; Jung, Y.H. Tetruhedron
Page 119 and 120: (a) Adams, Z.M.; Jackson, R.F.W.; P
Page 121 and 122: (a) Roemmele, R.C.; Rapport, H. J.
Page 123 and 124: - - 68. Gawley, R.E.; Aubé, J. Pri
Page 125 and 126: pyridoxal phosphate dependent enzym
Page 127 and 128: Vinylglycines are also useful as sy
Page 129 and 130: In 1984, a modified Strecker synthe
Page 131 and 132: The main byproduct of elimination w
Page 133: , HO- OH Scheme 3.14 , 1) pb(OAc),
Page 137 and 138: Ser(a1d)-OB0 gave the desired olefi
Page 139 and 140: A tram relationship for H2IH3 in th
Page 141 and 142: 33 Summary The Cbz OB0 ester protec
Page 143 and 144: 67.1 (Ar_cH20), 63.2 @--a), 56.3 (a
Page 145 and 146: yielded a slightiy yellowish solid
Page 147 and 148: JAS Grigiarà ddition of trimethyls
Page 149 and 150: 6 158.9 (CONH), 107.4 (OB0 ester C-
Page 151 and 152: Rutjes, F.P.J.T.; Wolf, L.B.; Schoe
Page 153 and 154: (a) Tashiro, T.; Fushiya, S.; Nome,
Page 155 and 156: Sawada, S.; Nakayama, T.; Esaki, N.
Page 157 and 158: of Rheum rhaponticum over forty yea
Page 159 and 160: Glutamic acid derivatives are aiso
Page 161 and 162: syntheses exist for the functionaii
Page 163 and 164: 4.1.4 Synthesis of Optically Active
Page 165 and 166: 4.1.4.3 Catalytic HydrogeMrion The
Page 167 and 168: Scheme 4.10 C02Et CO*Et R=Me, Et, P
Page 169 and 170: stereochemicaî induction at the re
Page 171 and 172: protected glutamate did not adopt a
Page 173 and 174: Scheme 4.16 The first synthesis of
Page 175 and 176: stereoselectivi ty during electroph
Page 177 and 178: kt, when we repeated the synthesis
Page 179 and 180: CbzH Scheme 4.2û OH pTsW CbzH Figu
Page 181 and 182: 5.21 5.00 16.63 Figure 4.5: GCMS of
Page 183 and 184: Glu(y-Me)(OMe)OBO ester 4.73. Howev
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OB0 ester. Moreover, the stereochem
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Table 4.1: Optimilgtion of Methyiat
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Scheme 4.22 M'2aL O 2) 1) LiHMDS, P
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Table 4.2: Optimization of Hydroxyi
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Cb2H 1 OsO,. NMO acetone:H& OH m 2)
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The direct electrophilic azidizatio
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to the mesylate Alûû in 80% yield
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which were not isolated. ESI-MS and
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concentrateci reaction mixhue of 4.
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and during acid hydrolysis. HPLC an
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A general method for the synthesis
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Generai Procedure for Removd of Rot
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Same procedure as in 4.4.1. TU3 (1:
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Same procedure as in 4.4.3. [al% =
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ffom CH2Cl2) 3338,2962,2875, 1732,
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ester -0). 72.4 (OB0 ester w20), 65
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4m4.11 5-Methyl-(~,~-2-[(betl~gIo~)
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= l2JHz, CbzCHHO), 3.87-3.78 (s + r
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1016; HRMS (FAB) calcd for (M + H+)
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7.3&, CHZCH~), 0.78 (s, 3H, OB0 est
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hotu before benzyl brornide (0.21 m
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1 H. J = 10.3Hz (detennined by deco
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378.22; Anal. cdcd for CI9Ha07: C,
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(ça), 164.0 EONH), 143.3 (Cbz==).
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min. The solvent was removed under
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173.8 c=O), 156.3 CONH), 137.6 ( Cb
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mp. 1 16- 1 165°C; [al2'D = -2 1 .
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(3:2 Et0Ac:hexanes) to give 4.99 (1
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Cbz-L-Glu(Z-B,y-dehydro)(OMe)OBO 49
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(CbzQI20), 57.4 (am, 39.8 (yCJS2),
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3.7, 10.7, 14.5Hz. BCHH), 0.76 (S.
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TLC (1:1, EtOAc:Hex), Rc = 0.35; 'H
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1515, 1227, 1048, 1016,909; ESI-MS
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(Cbz=@), 128.5, 128.2, 128.1 (a-=),
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TU3 ( 1 : 1, EtOAc:Hex), Rf = 0.17;
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4-4-46 (2S,4S)-2-My14aminopentanedi
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give 0.020 g (54%) of the monoamrno
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1. (a) Virtanen, A.I.; Berg, A.M. A
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Bory, S.; Dubois, J.; Gaudry, M.; M
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(a) Ezquerra, J.; Pedregal, C.; Ymr
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(a) Blaskovich, M.A.; Lajoie. G.A.
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Rathke, M-W.; Sullivan, D.F. J. Am,
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Chapter Five Stereoselective Synthe
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of p-methylaspartate 5.1 to glutama
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OAc Ac kfN&O@ 5.8 C02Et AC lU&02Et
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of 2:7 respectively, both of which
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MH). Changing the reaction conditio
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Garner's aldehyde 1.53 was also use
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Rotected ~-aminoaspartate Sm6 was s
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amount of unreacted starting materi
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provided crystals of sufficient qua
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5.2.2 Addition of Other AIkylation
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Scheme 5-18 We also investigated az
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5.2.5 Discussion of the Stereochist
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face) to give rise to the B,3S ster
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The synthesis of threo-L-b-substitu
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TU3 (1: 1, CHC13:EtOAc, 1 % AcOH) R
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156.0 (ÇONH), 1 36.2 (Cbz*), 128.5
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ester COI3), 30.6 (p-cH2), 14.1 (OB
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extracted with EtzO (3 x 25 d), the
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TU3 (1: 1, EtOAc:Hex), Rr = 0.48; '
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63 MHz) 6 175.9 cd), 156.0 EONH), 1
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175.1 CC-O), 155.8 (CONH), 136.1 (C
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'H-NMR @20, 300 MHz) 6 7.26-7.03 (m
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12.7Hz, CbzCHHO), 5.02 (ci, lH, J =
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TU3 ( 1 : 1, EtOAc:Hex), Rr = 0.40;
Page 317 and 318:
1. 2. 3. 4. 5. 6. 7. 8. 9. IO. 11.
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Eager, R.G. Jr.; Baltimore, B.G.; H
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- - Sardina, F.J.; Paz, MM.; Femihd
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Chapter Si Solid Phase Synthesis of
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eactions such as the Ugi condensati
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Dehydroamino acids have also been u
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Pyroglutarnate was reduced into the
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. - 6.2.1 Synthesis of Resin-Bod BH
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" 6.29 NMM, CH& Scheme 6.11 The arn
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esin placed hem Figure 6.3: Experim
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Figure 6.4: MAS 13c-N..~ (500 MHz)
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Table 6.1: Addition of R'M~B~ to 6.
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63 Summ Attachrnent of Ser-OB0 este
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(S. 2H, CbzCHzO), 4.57-4.40 (m, 7H,
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I C-O), 7 1.9 (OB0 ester GHzO), 61.
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insed, altemating with dry DMF (5 x
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- MAS 'H NMR (Spin-Echd ms): 8 3.87
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6.4.16 (zs)-2-Pmmo-3-hydroruy-3-met
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O.; Gilliarn, CL.; Boisclair, M.D.;
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38. Rakita, P.E.; Silverman, G.S. W
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of these important derivatives due
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the glutamate dimer. It may also be
Page 361 and 362:
Rose, N.G.W.; Blaskovich, M.A.; Won
Page 363 and 364:
Appendices
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Table 1, Cryatrl data and .tructuse
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Tabla 3. Bond langths [Al and amglr
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- - - . - Table 5. Eyârogen coordi
Page 371 and 372:
Calculation of Free Energy Dinerenc
Page 373 and 374:
Table 1. Crymtal data and mtructure
Page 375 and 376:
. Tabla 3. Bond lenpths [il and rng
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X-Ray Crystallographic Data for Com
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4 Tabla 2. Atomic coordinates 1 x 1
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2 3 ? able 4. Aniiotsopic dfmplacea
Page 384 and 385:
Calcdation to Determine Resin Loadi
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