ライフサイエンスコーパス: tautomer

1 exoamino group gave its 1H-pyrrol-3-aminium tautomer.

2 valuable method to identify the predominant tautomer.

3 stidine exclusively forms the less common pi-tautomer.

4 l bound ferrous porphyrin, i.e., its valence tautomer.

5 cence spectrum of the active PLP ketoenamine tautomer.

6 a fast equilibrium lying far toward the keto tautomer.

7 e configuration and the neutral hydroxyimine tautomer.

8 xhibit a significant amount of the enolimine tautomer.

9 phenolic hydroxyl group in the hydroxyimine tautomer.

10 ich is negatively charged in the ketoenamine tautomer.

11 ct is an unanticipated dearomatized thiazole tautomer.

12 ter acylation, doripenem adopts the Delta(1) tautomer.

13 rbene quinoline-2-ylidene is not formed as a tautomer.

14 e reactive imine over the unreactive enamine tautomer.

15 xcited state of the N1H, 6-keto, N7H guanine tautomer.

16 se, was identified as an adenylated thiazole tautomer.

17 talyst via the unusual 1',4'-iminopyrimidine tautomer.

18 ppm on formation of the 1,4-iminopyrimidine tautomer.

19 ocess rise to 17.0-27.1 kcal/mol in the keto tautomer.

20 temperatures with no traces of the hydrazone tautomer.

21 sized to represent the pure extremes of each tautomer.

22 r, consistent with its role as the catalytic tautomer.

23 t evolve spontaneously to a stable methylene tautomer.

24 ent way to measure the concentration of each tautomer.

25 followed by the 4-hydroxycoumarin open-chain tautomer.

26 e N-protonated, rather than the O-protonated tautomer.

27 e conformations of the two neutral histidine tautomers.

28 idant activity for the both of CurE and CurK tautomers.

29 olution as equilibrium mixtures of N1 and N2 tautomers.

30 onfirmed the dynamic stability of these rare tautomers.

31 etic acid exist as a pair of interconverting tautomers.

32 H-Keto, N9Ha-Enol(trans), and N9Hb-Enol(cis) tautomers.

33 were identified as the H1 and H3 keto-amino tautomers.

34 of approximately 54 ps for both TA* and TB* tautomers.

35 cumulation of damaging radicals or mutagenic tautomers.

36 to distinguish among rapidly interconverting tautomers.

37 is slightly more stable than the imine-amine tautomer (14) (DeltaG = 0.2-0.7 kcal/mol, within the err

38 the imine-amine isomer over the ene-diamine tautomer (18) (DeltaG = 7.2-8.9 kcal/mol).

39 rmation of a higher-energy protonated phenyl tautomer (2H(+)) prior to C-C bond breaking would produc

40 lting in normal (340 nm) and proton-transfer tautomer (480 nm) emissions with an overall quantum yiel

41 und exists as the selone rather than selenol tautomer, a result that is in accord with DFT calculatio

42 n the relative stabilities of carbaporphyrin tautomers, a series of aromatic and nonaromatic structur

43 (+)), with its higher energy ring-protonated tautomer allowing the requisite C-C bond cleavage.

44 isted as a broad ensemble of interconverting tautomers, among which enolic forms dominated.

45 , the H37 structure is shifted toward the pi tautomer and less cationic tetrads, consistent with fast

46 eaction occurs via N-acylation of the lactim tautomer and that cation-pi interactions play a key role

47 data shows a strong correlation between the tautomer and the H-bond accepting ability of the solvent

48 itated the identification of the most stable tautomers and conformers for both neutral and anionic AA

49 (hydrogenation) states, displaying different tautomers and conformers.

50 We identified several KP1212 tautomers and found that >60% of neutral KP1212 is prese

51 Inclusion of all tautomers and ionization ligand species was essential: t

52 h as DNA bases or proteins, possess numerous tautomers and isomers that lie close in energy, making t

53 as an equilibrating pair of interconverting tautomers and not as a single symmetric resonance hybrid

54 as an equilibrating pair of interconverting tautomers and not as a single symmetric structure not on

55 atic resonance structure representations, in tautomers and pericyclic reaction partners in which only

56 In silico modelling of apocynin tautomers and radical species into human NAT crystal str

57 yrrolopyridine analogues, forming up to five tautomers and seven ionization species under experimenta

58 These tautomers and their distinct environmental sensitivity p

59 omer in the wild-type protein to the Ndelta1 tautomer, and an altered motional behavior of the associ

60 on with aldehydes, gave exclusively the keto tautomer, and no isolable enol.

61 und covalent complexes will also prefer this tautomer, and that the 4'-aminopyrimidine of ThDP partic

62 fast exchange among the tau tautomer, the pi tautomer, and the cationic state due to proton transfer

63 Hx binds to human PNP as the N-7H tautomer, and the N-7H (1)H and (15)N chemical shifts ar

64 The dipole moments of these tautomers are also experimentally determined and compare

65 The H-bonding complexes for 7-H and 9-H tautomers are characterized by higher aromaticity and a

66 While changes in the two tautomers are not large in the Soret band region, the di

67 copy of the HIV-1 primer binding site, both tautomers are observed and show differential sensitivity

68 reduces the enamide preference so that both tautomers are present at equilibrium.

69 Because both tautomers are seen simultaneously, these two enzymes pro

70 e energy differences between the B-N and B-O tautomers are small, explaining the formation of both.

71 hemiketal diastereomers, with an open-chain tautomer as a minor component.

72 ropose that the guanine base adopts the enol tautomer as N1 binds to Fe4 and the O6-H hydroxyl group

73 tautomers is shifted toward the ketoenamine tautomer, as a result of a conformational change affecti

74 h the formation of the 1',4'-iminopyrimidine tautomer, as also demonstrated for phosphonolactylthiami

75 ulted in the presence of 100(3)% of the enol tautomer at 300(5) K and 64(5)% of the enol at 671(7) K.

76 imarily forms the common (for histidine) tau-tautomer at neutral pH, while 4-fluorohistidine exclusiv

77 oximately 5, titrating to the N(epsilon)(1)H tautomer at neutral pH.

78 However, their less-stable enol tautomers, bearing OH groups adjacent to carbon-carbon d

79 al compartment not to be in the O-protonated tautomer but in the N-protonated tautomer with the preva

80 vated temperatures, the products are not the tautomers but rather dimers stemming from radical-radica

81 tonated at pH 7 and stabilizes the hydrazone tautomer by a short hydrogen-bonding interaction.

82 t rests on stabilization of the diamino enol tautomer by Dipp substitution, and could be attributed t

83 than the alternative, doubly hydrated trans tautomer by some 8.3 kcal mol(-1) .

84 ly planarized and charge-delocalized enolate tautomers by anion-pi interactions.

85 f P can base-pair with adenine and its amino tautomer can base-pair with guanine.

86 lexes, while the relative emission of the H3 tautomer can be used to detect single nucleotide polymor

87 nt in comparable amount in solution; the two tautomers can also be selectively precipitated in differ

88 he experimental characterization of a unique tautomer challenging.

89 t intermediate via the 1',4'-iminopyrimidine tautomer, characteristic of all intermediates with a tet

90 '-iminopyrimidine and the 4'-aminopyrimidine tautomers coexist on the E1 component of human pyruvate

91 that the substrate is present in a hydrazone tautomer conformation.

92 able conformers of the neutral keto and enol tautomers differ by less than 1 kcal/mol in terms of ele

93 Below 50 K, the hs-Co(II) tautomer displays temperature-independent relaxation to

94 spectra and likely reflects variation in the tautomer distribution of the holoenzyme.

95 The tautomer distribution sampled in the gas phase very much

96 dated and then used to obtain pKa values and tautomer distributions for histidine residues of an invi

97 ectron electrophilicity of the Mn(O) valence tautomers dominate OAT reactivity and do not follow the

98 elated (R2= 0.90) and were dominated by ring tautomer effects and intermolecular interactions.

99 0 nm are resolved, which are ascribed to the tautomer emission resulting from the first and second pr

100 ransfer takes place, rendering a record high tautomer emission yield (0.18 in toluene) and the genera

101 ulting in TA* (560 nm) and TB* (650 nm) dual-tautomer emission.

102 ces in the electric dipole moment of the two tautomers, estimated from density functional theory calc

103 re NMR study suggests existence of the azine tautomer even at higher temperatures with no traces of t

104 d metal ion complexation, where the enol-azo tautomer exhibits much greater affinity for metal ion bi

105 The relative stabilities of the tautomers for each series were computed, and the bond le

106 on on the presence of multiple conformers or tautomers for intermediates within a complex reaction pa

107 terior methylenes are present in the favored tautomers for quatyrin.

108 pair, which is ascribed here to a rare enol tautomer form of the thymine, was observed at the end of

109 the base pair radical anions are present as tautomers formed by interstrand PT.

110 implies that the opposite reaction (and the tautomer forming step), a radical-radical disproportiona

111 The tautomers G, GN7H, and GHN7H support vertically bound va

112 modynamically more favored gaseous phenoxide tautomer, generated from the same aqueous solution of p-

113 y the most stable, a noncanonical, amino-oxo tautomer (GN7H), as the latter does not support an adiab

114 DFT calculations suggest that the observed tautomer has a lower energy than the alternative, doubly

115 The equilibrium between the keto- and enol-tautomers has been extensively studied and quantified in

116 sites of native adenine, complexes with N7-H tautomers have also been considered.

117 and the hydrogen atom affinities (HA) of the tautomers have been used to calculate the reaction entha

118 ons provide structural evidence for the rare tautomer hypothesis of spontaneous mutagenesis, a long-s

119 and defines a sequence context for the "rare tautomer hypothesis" as a mechanism for inducing transit

120 To test the multiple tautomer hypothesis, we used 2D IR spectroscopy, which o

121 cyclic hemiketal tautomer is the most stable tautomer in aqueous solution, followed by the 4-hydroxyc

122 depends on stabilization of a rare cytosine tautomer in C.O6MeG-polymerase complexes.

123 d in hydrogen-bonding solvents and the CH(2)-tautomer in CH(2)Cl(2).

124 llowed by hydrolysis of the enamine or imine tautomer in cis-CaaD versus direct hydration of the alle

125 lesser extent relative to its neutral imine tautomer in primary amine catalysts having outer-sphere

126 AGTT exists as tautomer in solution form and our studies indicate that

127 The existence of each tautomer in solution has been shown to be strongly solve

128 dentification for the active form of the PLP tautomer in the active site of DDC.

129 preparation of the nonaromatic 4H-imidazole tautomer in the core.

130 e participation of the 1',4'-iminopyrimidine tautomer in the mechanism.

131 is22 switches from the predominant Nepsilon2 tautomer in the wild-type protein to the Ndelta1 tautome

132 [6-18O]ImmH to establish that O6 is the keto tautomer in TvPNP x ImmH x PO4, causing an unfavorable l

133 idual ring and of the whole molecule for all tautomers in ionic complexes is very similar to that obs

134 oncluded that this monoanion is a mixture of tautomers in rapid equilibrium, rather than a single sym

135 an order of magnitude from that of the free tautomers in solution.

136 xo (G) and both amino-hydroxy (GH and GHN7H) tautomers in the beam, not only the most stable, a nonca

137 ical) and "N7" (proton on N7 rather than N9) tautomers in the gas phase, as both are calculated to be

138 Guanine is calculated to have several stable tautomers in the gas phase, in contrast to in solution,

139 he distinct spectral changes between the two tautomers in the Q-band region provide a convenient way

140 ts (hydroquinone, indolequinone, and its two tautomers), in arrangements that contain an interior por

141 n the transient species and is assigned as a tautomer, in which a C6(H) of the transient radical is t

142 a are consistent with a substrate imine/enol tautomer intermediate being formed prior to the formatio

143 to be studied whether formation of the keto tautomer is a general feature of all thiamin enzymes, as

144 Formation of the keto tautomer is associated with a loss of aromaticity of the

145 e light (lambda = 400-850 nm), the hs-Co(II) tautomer is formed.

146 whose tautomeric preference toward the azine tautomer is in the range of 3-8 kcal/mol.

147 le proton transfer involving the ketoenamine tautomer is observed after treatment with either gaseous

148 In the dry solid, only the enolimine tautomer is observed.

149 pA)}, only the anti orientation of the imino tautomer is possible.

150 irrespective of the solvent the carboxylate tautomer is preferred in solution, while the opposite ho

151 of -300 mV (vs Ag/AgCl), while the enol-azo tautomer is strongly favored at potentials positive of t

152 The red-shifted H1 tautomer is strongly favored in matched (-)/(+)PBS duple

153 The enol tautomer is the form that predominates in the subsequent

154 ble to all thiamin diphosphate enzymes: this tautomer is the intramolecular trigger to generate the r

155 aphthoquinones series indicated that the 1,4-tautomer is the more stable and biologically relevant is

156 that the 4-hydroxycoumarin cyclic hemiketal tautomer is the most stable tautomer in aqueous solution

157 The distribution of cofactor tautomers is dramatically affected by the ligation state

158 carboxylate subsite, the equilibrium between tautomers is shifted toward the ketoenamine tautomer, as

159 Interconversion between individual tautomers is shown to proceed via tight ion-pair interme

160 study of the relative energies of different tautomers, isomers, and supramolecular complexes support

161 ransfer, to give the poorly emissive excited tautomer [L...H-F](-)*.

162 The interchange among KuQ tautomers leads to substantial spectral variations of th

163 istribution of the enolimine and ketoenamine tautomers, likely as a result of a more polar active sit

164 We assigned the species as an iminoquinone tautomer (LTI) of lysine tyrosylquinone (LTQ), the organ

165 Ph)Ad (3) (R-H = ethylbenzene) or aminoalkyl tautomer [Me(3)NN]Ni(eta(2)-CH(Ph)NHAd) (4) (R-H = tolue

166 E, which is nearly +700 mV above its valence tautomer Mn(V)(O)(TBP8Cz) (Ered = -0.05 V).

167 s ((13)C(gamma), , and ) for each of the two tautomers, N(delta1)-H and N(epsilon2)-H, and the proton

168 odology indicates that the quinolinol (enol) tautomer (not detected by other means) may be accessible

169 efore, 1 exists as a pair of interconverting tautomers, not as a single symmetric structure with its

170 arly orthogonal to that of the proposed keto tautomer observed in the S112A.HOPDA complex.

171 Calculations suggested that the dominant tautomer of (Ph)ImC in methanol solution is identical to

172 ental conditions, we have only the canonical tautomer of 1,N(6)-ethenoadenine present.

173 pseudoanisatin, here identified as the chain tautomer of 1.

174 s revealed the first example of a stable cis tautomer of a free-base porphyrin, the long-postulated i

175 The enediamine tautomer of a variety of substituted amidine free bases

176 teristic of the canonical 4'-aminopyrimidine tautomer of bound thiamin diphosphate (AP).

177 he calculations suggest that the nonaromatic tautomer of CAIR (isoCAIR) is only 3.1 kcal/mol higher i

178 lization/proton transfer that forms the H-4a tautomer of carbazole.

179 omeric equilibrium toward the rare imino-oxo tautomer of cytidine stabilizes the f(5)C34*A base pair

180 ross-link G(N2)-to-G(C2) and the amide-amide tautomer of G(N1)-to-G(C2).

181 ctions to stabilize the unfavored N(delta1)H tautomer of His-45, thereby rendering the N(epsilon2) im

182 does not mispair effectively with the minor tautomer of isoG.

183 dominantly by binding of the C=C of the enol tautomer of MP to the surface, while simultaneously opti

184 roceeds through the intermediacy of the keto tautomer of naphthol.

185 en is stereorandom, suggesting that the enol tautomer of oxaloacetate is the product; this expectatio

186 en bonding characteristics whereby the imino tautomer of P can base-pair with adenine and its amino t

187 2C show that the enzyme oxidizes the enamine tautomer of P2C but do not distinguish among several pos

188 he bond between N(1) and C(6) in the enamine tautomer of P2C, ruling out alternative paths that requi

189 DFT calculations of the stable tautomer of selected (Ph)ImC analogues suggested a relat

190 band near 300 nm reports on the 1',4'-imino tautomer of ThDP, methods are now available for kinetic

191 lkylation by the reactive 2,3-butadienal (3) tautomer of the 3-butynal turnover product of 1, aldehyd

192 hesized to create models for the 1',4'-imino tautomer of the 4'-aminopyrimidine ring of thiamin dipho

193 {d(ApA)} induces formation of the rare imino tautomer of the bases with a concomitant substantial dec

194 The isoxazol-3-one tautomer of the bicyclic isoxazole, 5,6,7,8-tetrahydro-4

195 C react with benzaldehyde to give the ketone tautomer of the Breslow intermediate, whereas the AAAC f

196 C or mC prior to deamination via an E-imino tautomer of the C or mC or by a nontemplated mechanism i

197 ations show preferences for the amide-iminol tautomer of the classical cross-link G(N2)-to-G(C2) and

198 A valence tautomer of the closed-shell Mn(V)(O)(TBP8Cz) can be sta

199 ol the formation of either a keto or an enol tautomer of the products, again resulting in vastly diff

200 The lowest energy tautomer of the protonated form is calculated to be [WOS

201 ation (topomerization) of the "sigma-bonded" tautomers of 1H[B(Ar(F))4], which proceeds according to

202 3)C and (19)F NMR chemical shifts, from both tautomers of 2-fluorohistidine and 4-fluorohistidine in

203 Using 2D IR spectroscopy, lactam and lactim tautomers of 6-chloro-2-pyridone and 2-chloro-4-pyridone

204 tom transfer (OAT) reactivity of two valence tautomers of a Mn(V)(O) porphyrinoid complex was compare

205 Assuming that ESA by the corresponding tautomers of adenine is unchanged, we estimate the popul

206 lculations here show that fC and the neutral tautomers of caC are acidic relative to other TDG substr

207 o the specific contributions of five neutral tautomers of cytosine prior to ionization.

208 As a consequence, DgAS binds the furanoid tautomers of fructose through a weak network of interact

209 copy is used to study the four lowest energy tautomers of guanine, isolated in helium nanodroplets.

210 ution we conclude that both dominant neutral tautomers of hypoxanthine exhibit ultrashort excited sta

211 cal intersections for both prominent neutral tautomers of hypoxanthine.

212 present the synthesis of the "missing" keto tautomers of imidazolidinylidene-derived diamino enols,

213 dicating that major gas-phase conformers and tautomers of neutral AA do not support the intramolecula

214 been characterized for the four most stable tautomers of neutral guanine using a broad spectrum of e

215 arbaporphyrin structures, together with four tautomers of porphyrin and the related antiaromatic spec

216 Four tautomers of purine (1-H, 3-H, 7-H, and 9-H) and their e

217 putational analyses suggest that phenol-type tautomers of the pyrazolone ring are the active pharmaco

218 Intermolecular enol tautomers of Watson-Crick base pairs could emerge sponta

219 perchlorates, electronic isomers (or valence tautomers) of well-known iron(IV)-oxo porphyrin radical

220 undant proportion of this traditionally rare tautomer offers a compelling structure-based mechanism f

221 e for formation of the 1',4'-iminopyrimidine tautomer on binding of phosphonolactylthiamine diphospha

222 identification of the 1',4'-iminopyrimidine tautomer on four enzymes is almost certainly applicable

223 nment to the 1',4'-imino thiamin diphosphate tautomer on the enzyme, chiral by virtue of its fixed V

224 r the Michaelis complex, involving the amino tautomer, on both enzymes.

225 dynamically less favored gaseous carboxylate tautomer or the thermodynamically more favored gaseous p

226 (2) The rare 1',4'-iminopyrimidine ThDP tautomer participates in formation of ThDP-bound interme

227 d the sample is slowly heated, the hs-Co(II) tautomer persists until ca. 90 K, approximately 40 K hig

228 respectively, along with their corresponding tautomers (PNP)Ti=CHSiMe3(CH2tBu) (5) and (PNP)Ti=CHPh(C

229 The observed switching of the tautomer population occurs within a narrow range of appl

230 This model accurately predicts the relative tautomer populations versus applied potential, at interf

231 the measurement of site-specific pK(a)s and tautomer populations.

232 The enol tautomer possesses Cs symmetry with a planar ring and st

233 contrast to in solution, where the canonical tautomer predominates.

234 e tautomeric LAH adducts are compared to the tautomer preference energies of the LiH adducts and of t

235 ffinities are reported and used to ascertain tautomer preference.

236 er transition between the 4'-aminopyrimidine tautomer (presumed electron donor) and the thiazolium ri

237 d H/D exchange studies are used to ascertain tautomer prevalence for the 4-phenyl species.

238 ergies (AIEs) of specific gas-phase cytosine tautomers produced in a molecular beam.

239 Hydrolysis of the enamine or an imine tautomer produces acetoacetate.

240 Loss of an acidic proton from these three tautomers produces the same conjugate base structure.

241 s the equilibrium in favor of the oxoenamine tautomer (protonated Schiff base).

242 DFT studies were performed on a series of tautomers, protonated species, and anionic structures re

243 e but complementary quinonoidal and aromatic tautomers provide the Janus faces of the reactants and p

244 afforded the [3,3] electrocyclic ring-opened tautomers, rather than pyrans, in high yields.

245 the course of the ESI process influences the tautomer ratio.

246 nto thermodynamically more stable 1H- and 6H-tautomers, respectively, by removing of the benzyl-PG.

247 The fluorescence quantum yield of the ESIPT tautomers revealed a significant correlation with the ob

248 The same tautomer shift is also induced by heat inactivation of F

249 We propose that the tautomer shift results from loss of a stabilizing H-bond

250 aking the salt bridge, since the rate of the tautomer shift, following CO binding, increases with dec

251 found to diminish the rate and extent of the tautomer shift, suggesting a ketoenamine-stabilizing pho

252 N chemical shift for the 1,4-iminopyrimidine tautomer should serve as useful guides to the assignment

253 ations for each of the rings comprising both tautomers showed that while the central benzene ring los

254 Purine tautomer stability increases in the following series: 1-

255 the tris(hydrazone) [rather than tris(azo)] tautomer stabilized by resonance-assisted hydrogen bondi

256 he way to analyzing 13C NMR chemical shifts, tautomer states (from Cdelta2, Cepsilon1 shifts), and hy

257 e relative OAT and HAT reactivity of valence tautomers such as M(V)(O)(porph) versus M(IV)(O)(porph(*

258 ry (LC-MS/MS) were hydroxides and their keto tautomers, sulfates, sulfoxides, and N-oxides.

259 The G and GHN7H tautomers support dipole-bound states with the CCSD(T) v

260 s are associated with the normal (N( *)) and tautomer (T( *)) excited-state species that result from

261 ransfer, protonated HAL and ALH rearrange to tautomers that are detected as nondissociated anions in

262 These molecules were isolated as enol tautomers that exhibit intramolecular hydrogen bond and

263 are aromatic, while in the corresponding oxo tautomers the nitrogen-containing ring is essentially no

264 For 9-H and 7-H tautomers the order is reversed.

265 His37 undergoes fast exchange among the tau tautomer, the pi tautomer, and the cationic state due to

266 phy to be exclusively the quinolinone (keto) tautomer, though experimental cyclic voltammetry support

267 ly thermally stable photogenerated hs-Co(II) tautomer, thus providing an excellent handle for molecul

268 n of the pyridyl ligand (or its pyridylidene tautomer) to the alpha-carbon of the vinylidene, followe

269 The reactivity of the valence tautomer (tpfc(+*))Mn(IV)(OH) is compared to that of (tp

270 t we may have a mixture of the keto and enol tautomers under our conditions in the gas phase, althoug

271 hich the proportions of the 5- and 6-methoxy tautomers vary systematically, we demonstrate that solid

272 n forms a mixture of three different valence tautomers (VTs) in CH2Cl2 or 1,2-C2H4Cl2 solutions.

273 CSiMe3)(PMe2Ph) (3a) and its bis(alkylidene) tautomer W(CH2SiMe3)2(=CHSiMe3)2(PMe2Ph) (3b) was simila

274 3(CSiMe3)(PMe3) (1a) and its bis(alkylidene) tautomer W(CH2SiMe3)2(=CHSiMe3)2(PMe3) (1b) has been fou

275 ibration of the thermodynamically disfavored tautomer was attempted with acids and bases but could no

276 In solution, the NH(3)-tautomer was favored in hydrogen-bonding solvents and th

277 energetics of neutral and cationic cytosine tautomers were determined using explicitly correlated me

278 No traces of 4-oxoquinoline tautomers were found in the experimental IR spectra, rev

279 Using (TD)-DFT calculations, the tautomers were identified as the H1 and H3 keto-amino ta

280 Both tautomers were isolated as their respective tetrakis(pen

281 constants, K(a)(KH), for the different keto tautomers were measured spectrophotometrically at 25 deg

282 rodiol metabolites, isolated as their ketone tautomers, were obtained from meta and ortho methoxyphen

283 and -10.49 kcal/mol) for less stable purine tautomers when the proton acceptor is located in the fiv

284 l effects favor these conformers of the keto tautomer, which do not support an intramolecular hydroge

285 and significant antiaromaticity in the keto-tautomer, which is by no means intuitive.

286 ment of gas-phase guanine with the canonical tautomer, which is not the most stable in the gas phase,

287 otonation of the metal-stabilized rare imino tautomer, which takes place at pKa approximately 7.5 in

288 the energetic degeneracy of the two valence tautomers, while not affecting the activation barrier.

289 ent with a strong base produce the 1,4-imino tautomer whose UV spectrum indicates a maximum between 3

290 esulted in conversion of adduct I to the azo tautomer with a blue shift of the lambda(max) to 420 nm,

291 In contrast, 1-naphthol is the preferred tautomer with a Delta(t)H = -9.0 kcal mol(-1).

292 coordinated to the metal ion, but involves a tautomer with a more effective Lewis acid and more react

293 theory calculations showed that a nonplanar tautomer with four internal hydrogens was favored, in ag

294 -protonated tautomer but in the N-protonated tautomer with the prevalence of a keto-enamine resonance

295 C-(P-tetraone)2H leads to the formation of a tautomer with trans inner hydrogens with one residing on

296 Dicarbaporphyrin and tricarbaporphyrin favor tautomers with an internal methylene group, while two in

297 We have investigated all warfarin tautomers with computational and NMR approaches.

298 G reveals the existence of two ground-state tautomers with significantly shifted absorption and emis

299 All thiadiazines were found as the 4H tautomers with the heterocyclic ring puckered along the

300 of beta-dicarbonyl systems, as their enamine tautomers, with benzoquinone has been applied to a wide