A theoretical study on the molecular mechanism for the normal Reimer–Tiemann reaction

Castillo, Raquel; Moliner, Vicent; Andrés, Juán

doi:10.1016/s0009-2614(00)00005-1

Cited by 8 publications

(3 citation statements)

References 31 publications

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“…Laboratory simulation of the formation and reactions of organic molecules in the interstellar medium is a difficult task. On the other hand, during the last three years there is a rapidly growing interest for the use of the quantum chemical ab initio and density functional theory (DFT) methods to study chemical mechanisms and energetics of interstellar organic reactions, mainly in the gas phase. − While many researches in the field try to employ the true electron correlation models (for example 11-14a,15-18,23-26 ), the use of the B3LYP hybrid functional becomes more and more frequently reported. ,,,, Besides the interstellar chemistry, this method was used in the studies of many other organic reactions − (some of them involving gaseous amino acids and related compounds 51,55,58 ). The reason for this growing popularity can be understood from the reported comparison of B3LYP to much more expensive methods: in many cases the DFT results (geometries and energies) were noted to be in a remarkably good agreement with those obtained by the higher-level theories CISD, CCSD, CASSCF 14a,17,28-31,58 and G2 23,30,59 or demonstrated even the top performance approaching, as the ideal case, to experimental data. 14b-e,,,,,,…”

Section: Introductionmentioning

confidence: 99%

Formation of Amino Acid Precursors in the Interstellar Medium. A DFT Study of Some Gas-Phase Reactions Starting with Methylenimine

Basiuk

2001

J. Phys. Chem. A

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To evaluate feasibility of the formation of amino acid precursors in dense interstellar clouds from methylenimine, HCN, ‚CN radical, water, and ‚OH radical, stationary points for four gas-phase reactions have been computed at the B3LYP/6-311++G(d,p) level of theory. All the reactions are exothermic. For the reaction HNdCH 2 + HsCtN f H 2 NsCH 2 sCtN, three high-energy transition states have been found (energies of ca. 23-33 kcal mol -1 relative to the reactant level) which do not allow this reaction to occur as a purely gas-phase process. The same conclusion has been done for the further glycine amide formation according to the pathway H 2 NsCH 2 sCtN + H 2 O f H 2 NsCH 2 sC(dO)sNH 2 , where three transitions states have been obtained as well, one of them having relative energy of ca. 52 kcal mol -1 . Reaction HNd CH 2 + ‚CtN f H 2 NsC(‚)HsCtN (>70 kcal mol -1 exothermic) exhibits no positive barriers at the theoretical level employed; it is the only one unconditionally feasible in the gas-phase. Despite the fact that for reaction H 2 NsCH 2 sCtN + ‚OH f H 2 NsC(‚)HsC(dO)sNH 2 (ca. 60 kcal mol -1 exothermic) four transition states have been found, it might also appear plausible under the interstellar conditions for the following reasons: all the barriers are associated with exclusively proton-transfer processes; only one of them is positive, and three lay below the level of reactants; for the only positive barrier, proton tunneling might facilitate the reaction. Radical products H 2 NC(‚)HCN and H 2 NC(‚)HC(dO)NH 2 forming in the latter two cases have a free valence at the carbon atom corresponding to R-C atom in the molecules of biological amino acids. Combining them with a vast variety of open-shell interstellar species is suggested as a possible route to diverse amino acid derivatives in dense molecular clouds.

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Section: Introductionmentioning

confidence: 99%

Formation of Amino Acid Precursors in the Interstellar Medium. A DFT Study of Some Gas-Phase Reactions Starting with Methylenimine

Basiuk

2001

J. Phys. Chem. A

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“…In this step, 14 could be obtained from 13 by Duff formylation. [16][17][18][19][20][21][22][23][24] from water. However, for Duff formylation of 13, the influence of a small amount of water can almost be neglected and even 80-90% acetic acid aqueous solution allowed the reaction to proceed.…”

Section: Stagementioning

confidence: 99%

A New Route for the Synthesis of the Repaglinide Key Intermediate 3-Ethoxy-4-Ethoxycarbonylphenylacetic Acid

Zhang

Liu

Niu

et al. 2016

Journal of Chemical Research

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A new method is described for manufacturing 3-ethoxy-4-ethoxycarbonylphenylacetic acid, which is a key intermediate of the antidiabetic drug repaglinide, starting from 3-hydroxyphenylacetic acid and involving esterification, formylation, oxidation, etherification and selective hydrolysis. The effect of reaction temperature, time, solvent and substrate ratios on the yield were studied in detail and the optimal conditions are presented in the paper. The new method makes the scale-up operation easier and the environmental problems are fewer. The impurities in the intermediate of the new route were also determined. Characterisation of the product and intermediates involved was achieved by FTIR, 1H NMR, 13C NMR, HRMS and DSC.

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“…Only a computational study of the R-T reaction between the conjugate anion of pyrrole and dichlorocarbene with one water molecule has been reported. 9 From the carbene adduct (I1N), the intramolecular H [1,2] hydrogen shift transition state (TS) was shown to be the rate-limiting step. However, an intermolecular hydrogen shift would be more likely than an intramolecular one, which has a three-membered ring strain TS geometry.…”

Section: Introductionmentioning

confidence: 99%

A significant role of alkaline cations on the Reimer–Tiemann reaction

Yamabe

Fukuda

2011

Org. Biomol. Chem.

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The Reimer-Tiemann (R-T) reaction was investigated by DFT calculations. A model composed of CHCl(3), PhO(-)(Na(+))H(2)O and [NaOH(H(2)O)(2)](2) was employed for geometry optimizations. A K(+)-containing model was also investigated. The dichlorocarbene reagent, which has been thought of for a long time, was found to intervene only transiently in the carbenoid form. In this form, the Na(+) (or K(+)) coordination to CCl(2) enhances its electrophilicity toward C(6)H(5)O(-). The counter ion also works to stabilize the precursor phenoxide ion and intermediates of the substituted phenoxides in the hexagonal pyramidal coordination. The Na(+)-containing reaction consists of seven elementary processes, (K(+), six ones) with extremely high exothermicity and spontaneity.

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A theoretical study on the molecular mechanism for the normal Reimer–Tiemann reaction

Cited by 8 publications

References 31 publications

Formation of Amino Acid Precursors in the Interstellar Medium. A DFT Study of Some Gas-Phase Reactions Starting with Methylenimine

Formation of Amino Acid Precursors in the Interstellar Medium. A DFT Study of Some Gas-Phase Reactions Starting with Methylenimine

A New Route for the Synthesis of the Repaglinide Key Intermediate 3-Ethoxy-4-Ethoxycarbonylphenylacetic Acid

A significant role of alkaline cations on the Reimer–Tiemann reaction

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