ライフサイエンスコーパス: racemization

1 thod is simple, high-yielding, and free from racemization.

2 d hydrolysis products in high yields with no racemization.

3 of alcohols, a reaction relevant to lactate racemization.

4 rresponding chiral amines without detectable racemization.

5 orresponding unsaturated amino acids without racemization.

6 longer reaction times, the catalyst effects racemization.

7 n without undergoing thermal or photoinduced racemization.

8 s of the rates or mechanisms of halonium ion racemization.

9 minoxy peptides 10a,b in good yields without racemization.

10 promiscuous, catalyzing both dehydration and racemization.

11 ees C for several months without any sign of racemization.

12 mino acid derivatives with mimimal levels of racemization.

13 zed by the wild-type enzyme exceed those for racemization.

14 The second step was assigned to complex racemization.

15 hat metalation leads to a much lower rate of racemization.

16 yield under mild conditions with no signs of racemization.

17 rt-bound ACC in good yields and with minimal racemization.

18 n of configuration with no detectable (< 6%) racemization.

19 e linkages into pseudopeptide chains without racemization.

20 lized effectively through elevated levels of racemization.

21 acts as the catalytic acid during l-alanine racemization.

22 ion, at which point the preference is toward racemization.

23 ersion proceeds with good yield and shows no racemization.

24 ubstrates and furnished products without any racemization.

25 enantiopure amine starting materials without racemization.

26 ully coupled in good yields with very little racemization.

27 drug molecules is hampered by rapid in vivo racemization.

28 gnificant influence on the rate of substrate racemization.

29 mismatch with similar affinities and without racemization.

30 merization barriers were obtained by thermal racemization.

31 roceeds effectively, with very low levels of racemization.

32 substituted oxetan-3-ones without detectable racemization.

33 Searching for strategies to avoid racemization, a new class of light-driven molecular moto

34 loped silk dating technique using amino acid racemization (AAR) in conjunction with capillary electro

35 The Y265F mutant reduces racemization activity 1600-fold and only leads to format

36 e other hand, the S84T (which performs l-Ser racemization activity), S84A (good kcat but high Km for

37 o sonication at 0 degrees C resulted in >95% racemization after 24 h, as determined by circular dichr

38 e they exhibit sufficiently high barriers to racemization after ortho functionalization.

39 The inclusion of a biocatalytic racemization along with the PAM-catalyzed reaction moder

40 ffraction (SAXS), amino acid composition and racemization analyses.

41 ted, formally neutral state for catalysis of racemization and beta-elimination.

42 The dynamics of the racemization and catalytic and stoichiometric dynamic re

43 e value of the free energy of activation for racemization and deuterium exchange was calculated to be

44 Racemization and epimerization processes are often obser

45 ituents at N3 were found to suppress the C-5 racemization and in this way enabled the transfer of chi

46 roles for each of the two catalytic bases in racemization and inactivation, as well as the importance

47 ated temperatures, quantifying the extent of racemization and peptide bond hydrolysis using reverse-p

48 y morphometry of fossils dated by amino acid racemization and radiocarbon.

49 tetramethylethylenediamine (TMEDA) for both racemization and resolution of the title compound and th

50 sented that accounts for both base-catalyzed racemization and thioether formation at the hinge disulf

51 of L-tyrosine was optimized to avoid partial racemization and to allow a more efficient scale-up.

52 cted on a substrate incapable of competitive racemization, and accommodates the convergent preparatio

53 adienylruthenium catalysts were used for the racemization, and lipase PS-IM or CALB was employed for

54 o 9) on neat samples is irreversible without racemization, and the alumina-mediated equilibration is

55 reversed ester analogues were impervious to racemization, and their chemically distinct branches fac

56 odification sites should exhibit significant racemization as a side reaction to the main repair pathw

57 th serine and asparagine are able to undergo racemization as internally bound residues, which shows t

58 chirality, rotation about that axis leads to racemization as the system reaches equilibrium.

59 phenyl phosphines are shown to undergo rapid racemization at ambient temperature when exposed to cata

60 hiohydantoins turned out to be more prone to racemization at C-5 during the ring formation.

61 s developed and sold as racemates because of racemization at the chiral center of the 3-aminoglutarim

62 , and asparagine (Asn) did not show signs of racemization at the irradiation times studied; however,

63 The reaction proceeds without racemization at the stereogenic center of the amino acid

64 h the experimental geometry and the observed racemization barrier for 2 are in good agreement with co

65 We estimated that the racemization barrier for the two cyclochiral conformers

66 determination of absolute configuration and racemization barrier is also reported.

67 The N-C racemization barrier was found to be bigger than 25 kcal

68 dies demonstrate that the magnitude of their racemization barriers is primarily determined by the ide

69 The new helicenes possess low racemization barriers, as demonstrated by dynamic (1)H N

70 ve inversion experiments are used to measure racemization barriers.

71 n atom followed a retentive course with some racemization because of the involvement of a benzyllithi

72 mon step, their overall reactions (including racemization, beta-elimination of water, beta-eliminatio

73 0(5) M(-1) s(-1) for catalysis of amino-acid racemization by alanine racemase shows that the enzyme c

74 y, longer, compressed alkanes accelerate the racemization by applying pressure from the inside on the

75 aziridine enantioenriched and monitoring its racemization by CD spectroscopy.

76 isopropylbenzyl alcohol) also accelerate the racemization by facilitating the rotation of the glycolu

77 e beta-lactam framework was possible without racemization by treatment with SmI2.

78 t exist as a mixture of four isomers undergo racemization by two orthogonal mechanisms and are conver

79 o the incompatibility of the ruthenium-based racemization catalyst with the acylating agent (Ac(2)O)

80 p51, a comparison site, exhibited negligible racemization (D/L < or = 0.01).

81 25 in wild type mice, but substantially less racemization (D/L = 0.035) at Asp25 in PIMT-deficient mi

82 efficient decreased further to 0.58 when the racemization data from all mammals (including human) wer

83 ts support species specificity of amino acid racemization dating.

84 of the l-enantiomer either to d-enantiomer (racemization), degradation to undesired products or taut

85 ide (l-)L2 showed that the isomerization and racemization did not occur, indicating that the Asp degr

86 inely used in peptide chemistry for reducing racemization due to the increased reactivity.

87 Incorporation of a strap can slow racemization even further.

88 Racemization experiments show that phosphinic acid does

89 The rate of racemization for amides 54-57 is strongly dependent on t

90 ne and the development of effective and near-racemization free conditions for esterification of its h

91 ne and the development of effective and near-racemization free conditions for esterification of its h

92 ge in the final coupling reaction under near racemization free conditions.

93 9 was prepared by de novo synthesis using a racemization-free fragment coupling method.

94 A general and robust racemization-free protocol for the synthesis of a variet

95 This synthesis also features the racemization-free reductive removal of the chiral auxili

96 The racemization half-life of a compound within this series

97 Racemization has a large impact upon the biological prop

98 S-(Pg-alpha-aminoacyl)tripeptide 14 without racemization in 47-90% yields using N-(Pg-alpha-aminoacy

99 e of compounds with known rate constants for racemization in aqueous conditions was hitherto limited.

100 uilding blocks in a multistep system without racemization in excellent yields.

101 alogously to the alpha-amino esters, without racemization in high yields under mild conditions.

102 re we determine the genetic basis of lactate racemization in Lactobacillus plantarum.

103 -arylphosphine boranes were obtained without racemization in moderate to good yields and with ee up t

104 e performed to elucidate a new mechanism for racemization in Prins cyclization reactions.

105 sine and do not show a propensity to undergo racemization in vitro.

106 coupling products can be transformed without racemization into enantioenriched alpha-arylcarboxylic a

107 rylation of chiral alpha-aminoesters without racemization, involving Buchwald-Hartwig conditions.

108 y calculations indicate that the barrier for racemization is 9.9 kcal/mol, so the barrier for allylat

109 paddle size and only when the time scale for racemization is comparable to the time scale for segment

110 Lactic acid racemization is involved in lactate metabolism and cell

111 The racemization is limited by the polymer matrix only for p

112 In nonpolar solvents, however, the substrate racemization is primarily uncatalyzed.

113 fluoren-9-yl acrylate) [poly(BBPFA)], as its racemization is selectively driven by light without any

114 ally more hindered amides 23-24, the rate of racemization is significantly reduced.

115 The high barrier for this racemization is unique in probe studies of glasses and c

116 The degree of the racemization is, however, affected by the silane/carbony

117 er 231 and to a lower extent at Ser 229; and racemization/isomerization of l-Asp 243 to d-Asp and d-i

118 lens indicated an increase in truncation and racemization/isomerization with fiber cell age, whereas

119 ctical synthetic strategy was developed, and racemization issues were addressed using diastereomeric

120 yl paddles of varying sizes and studying the racemization kinetics as a function of temperature.

121 ormational isomers, and the determination of racemization kinetics of CD active chiral compounds.

122 iew of the role of segmental dynamics on the racemization kinetics of the binaphthyls and allow the i

123 ons, and the three-dimensional structure and racemization kinetics were studied by crystallography an

124 iate alpha-sulfonyl anion is more rapid than racemization, leading to a highly enantiospecific proces

125 We show that rate constants for racemization (measured by ourselves and others) correlat

126 These results support a two-base racemization mechanism involving Y265 and K39.

127 iments excluded the possibility of a thermal racemization mechanism.

128 will be dedicated to the design of efficient racemization methods as an important means of developing

129 silks" showed excessive levels of amino acid racemization not only for aspartic acid, but also for ph

130 alyze another reaction, N-succinylamino acid racemization (NSAR).

131 catalyze both OSBS and N-succinylamino acid racemization (NSAR).

132 We also propose that the racemization observed with 1,1'-carbonyldiimidazole (CDI

133 No racemization occurred when the procedure was applied to

134 The racemization occurs by a simple one-dimensional twisting

135 Here, we report that racemization occurs on both H220 and L214 on an IgG1 wit

136 Racemization occurs via an inversion-rotation process.

137 into the alpha-position of mandelate and the racemization of (R)-mandelate, after samples had been in

138 kcal/mol is estimated for the photochemical racemization of 1-methanesulfinylpyrene.

139 lind spot, we have measured the kinetics for racemization of 28 compounds using circular dichroism an

140 of alcohols with an active catalyst for the racemization of alcohols did not lead to DKR, due to the

141 In addition, nonenzymatic racemization of allantoin has been shown to occur at phy

142 In addition, this exchange reaction leads to racemization of allylic amines.

143 Racemization of amino acids is a common chemical degrada

144 nding of this study is that the mechanism of racemization of an alanine zwitterion in water is altere

145 Here we report the first study on racemization of an intrinsically chiral gold nanocluster

146 nd anabolic dehydrogenases to perform D-to-L racemization of arginine, which serves as prerequisite o

147 t that DauA and DauB are required for D-to-L racemization of arginine.

148 Parchment and rabbit skin glue exhibited racemization of Asp, as well as racemization of isoleuci

149 Racemization of Asp25 was independent of animal age over

150 In this work, we have used the racemization of aspartic acid as a marker for the turnov

151 In this study, we have quantified the racemization of aspartic acid to calculate the age of th

152 e in a particular tissue can, along with the racemization of aspartic acid, be used as a reliable mea

153 this key step did not cause any measurable C-racemization of boranophosphorylated amino acids 22.

154 The dependence of kcat on pH for the racemization of both (R)- and (S)-mandelates suggests th

155 of the three subunits, to prevent late stage racemization of carboxylate-activated phenylglycine-deri

156 of the three subunits, to prevent late stage racemization of carboxylate-activated phenylglycine-deri

157 ring an N-heterocyclic carbene ligand in the racemization of chiral alcohols is reported.

158 elimination may provide a mechanism for the racemization of chiral alcohols, which would undermine a

159 e-based mechanism for the ruthenium-mediated racemization of chiral alcohols.

160 thods, demonstrating that the intramolecular racemization of Delta and Lambda enantiomers of d0 Ti(IV

161 characterized and are known to catalyze the racemization of free proline or trans-4-hydroxyproline.

162 Glutamate racemase (MurI) catalyzes the racemization of glutamate; two cysteine residues serve a

163 ue exhibited racemization of Asp, as well as racemization of isoleucine (Ile) and phenylalanine (Phe)

164 Activation parameters for the racemization of K2[Ti2(3)] (H(2)2 = 2,3-dihydroxy-N,N'-d

165 cocci expressing the VanC phenotype involves racemization of L- to D-serine by a membrane-bound serin

166 n a soluble enzyme that catalyzes the direct racemization of L-serine to D-serine.

167 two distinct isomerization processes: faster racemization of mer-[Ti4(3)]2- by way of a Bailar twist

168 covered based on its ability to catalyze the racemization of N-acylamino acids (N-acylamino acid race

169 xadiene-1-carboxylate but also an accidental racemization of N-acylamino acids.

170 SBS from Amycolaptosis also can catalyze the racemization of N-acylamino acids.

171 Full racemization of poly-1b at +80 degrees C in toluene requ

172 Biosynthesis of D-amino acids from racemization of predominant L-enantiomers is catalyzed b

173 The facile racemization of protein-bound amino acids plays an impor

174 These data strongly support a stepwise racemization of stereoisomeric aldimine intermediates in

175 nantiomeric conformations with half-lives of racemization of t1/2 = 4150-25100 seconds at room temper

176 al catalytic roles, mediating both the rapid racemization of the 5-aryl dioxolanediones and the enant

177 of conditions under which the formation and racemization of the allyl iodide occurs.

178 ) due to the P-chirogenic center but without racemization of the amino acid or peptide moiety.

179 etic route, optimizing this process to avoid racemization of the azide intermediate, finally yielding

180 s proceed through a facile catalyst-mediated racemization of the beta-bromo-alpha-keto esters under a

181 At ambient temperature, racemization of the beta-position through a putative rev

182 n of the enantiomers allowed us to study the racemization of the chiral cluster, which reflects the f

183 The coalescence effects are assigned to racemization of the chiral ground-state conformation wit

184 degradation pathways, the first of which is racemization of the chiral sulfonium group, which takes

185 of the allylic alcohol side product and the racemization of the chirally unstable alpha-substituted

186 operties and free energies of activation for racemization of the garuganin and garugamblin diarylethe

187 Similar conditions also result in racemization of the H220 cysteine.

188 Racemization of the optical antipodes of these compounds

189 the capsule as inferred from monitoring the racemization of the optically pure alpha-alkyl deoxybenz

190 Racemization of the original N-terminal Asp to l-isoAsp

191 scaffold leading to THIQ 40 and showcase the racemization of the scaffold, pharmacokinetic studies in

192 The racemization of the stacks follows first-order kinetics

193 were included in the reaction mixture, rapid racemization of the starting material occurred allowing

194 oceeds via an S(N)2 pathway, and the partial racemization of the starting substrate was effectively c

195 group conversions in high yields without any racemization of the stereogenic benzodioxane C(2).

196 factor, likely the barrier to isomerization/racemization of the tartaric acid, which is hypothesized

197 acids may gauge its extent by the consequent racemization of their ee.

198 xperimental and computational studies on the racemization of these enolates, we have studied the ring

199 ible thermal bond homolysis at 95 degrees C; racemization of these metallacycles is also catalyzed by

200 These data and a dependence of alkoxide racemization on [PPh(3)] showed that the elementary beta

201 ndence of rate, isotope effect, and alkoxide racemization on phosphine concentration revealed unusual

202 exible optically active solutes undergo fast racemization (on the NMR timescale) their spectrum corre

203 vacuum at elevated temperatures without any racemization or decomposition.

204 e alpha-formyl vinylic stereocenters without racemization or olefin transposition.

205 hexenes at all levels of conversion, with no racemization or symmetrization taking place during the c

206 the case for interconversion of enantiomers (racemization) or exchange of enantiotopic sites in isotr

207 instein rearrangement can be enlisted as the racemization pathway in a dynamic kinetic resolution of

208 s enantio-enriched products and to study the racemization pathway of chiral 1,2-disubstituted adamant

209 ortance of Y265 in both the inactivation and racemization pathway.

210 The racemization proceeds by a multistep mechanism that is p

211 ure process was contributing to the observed racemization process accounting for the lower barriers i

212 probing of the helical self-assembly and the racemization process of these pi-conjugated OPV chromoph

213 Uncatalyzed racemization processes in atropisomeric diphenyl-like fr

214 ed at pH 6.9 and 8.9 from global analysis of racemization progress curves.

215 ), which enables the asymmetric synthesis of racemization-prone alpha-arylketones.

216 ch as N-terminal degradation, isomerization, racemization, pyroglutamyl formation, oxidation, and cov

217 Using the racemization rate found previously for the stable popula

218 The racemization rate is strongly dependent on the number of

219 ntly developed dating technique based on the racemization rate of aspartic acid was applied to dating

220 ur results interestingly indicated different racemization rates for specific amino acid residues.

221 henylalanine and tyrosine, inconsistent with racemization rates of these amino acids in authentic his

222 imation of silk textiles based on amino acid racemization rates.

223 silanes as a stereochemical probe results in racemization rather than inversion of the configuration

224 In addition, the aspartic acid racemization ratio of this specimen was also consistent

225 The results imply that the racemization ratios of aspartic acid, phenylalanine, and

226 A racemization reaction between 17alpha-estradiol and 17be

227 he carbon acidity enhancement in the alanine racemization reaction catalyzed by alanine racemase (Ala

228 the reason that this enzyme is capable of a racemization reaction on these substrates, whereas the o

229 tion of the alpha-proton in the (R)- and (S)-racemization reactions, respectively.

230 to a binding pattern that resembles the post-racemization state of the other enantiomer, i.e., each e

231 nantiomerization were determined by off-line racemization studies and/or by treatment of the plateau-

232 Racemization studies employing a series of sterically di

233 ly by means of dynamic HPLC measurements and racemization studies.

234 This racemization takes place at modest temperatures (40-80 d

235 oping leads to a substantial lowering of the racemization temperature.

236 er rate constants for general-base-catalyzed racemization that are usefully accurate.

237 A destructive BINOL racemization that competes with the enantioselective oxi

238 nantiopurity of CHDTN(Tos)(2) due to partial racemization that occurs during the derivatization step.

239 of the enantiomers has allowed the rates of racemization to be measured and hence the free energy ba

240 ium chloride) or protic solvents, can induce racemization, too.

241 in glue showed a significant increase in Asp racemization upon increasing irradiation time with rabbi

242 on of the borane was easily achieved without racemization using DABCO to obtain the free o-halogeno-a

243 result of a temperature change; therefore, a racemization via disassembly assembly is proposed.

244 Likewise, racemization was detected at significant levels on H220

245 The inversion barrier for racemization was determined experimentally to be 29 kcal

246 No racemization was observed during this reaction.

247 rmined by circular dichroism; no appreciable racemization was observed in low-molecular-weight deriva

248 Good yields without racemization were achieved under milder and simpler reac

249 tivation barriers (DeltaG(double dagger)) of racemization were determined.

250 The kinetics of GaSz racemization were followed by selective, double spin-ech

251 l modeling support a novel mode of sulfoxide racemization which occurs via a rhodium pi-allyl interme

252 The previously observed racemization, which occurred during the synthesis of fla

253 -role catalyst and accelerates the substrate racemization while catalyzing olefin hydrogenation.

254 he calibration curve showed a slower rate of racemization with a lower correlation (0.88).

255 ielded CBL(P113S), which catalyzes l-alanine racemization with a poor Km (58 mm) but a high kcat (22

256 The oxyacylation products are also prone to racemization without catalyst when heated alone; however

257 ological value, the calculations reveal that racemization would be sufficiently fast to render these