Reactions of the Carbonyl Group in Fluorinated Ketones

Gambaryan, N. P.; Rokhlin, E. M.; Zeifman, Yu. V.; Ch'ing-yun, Ch'en; Knunyants, I. L.

doi:10.1002/anie.196609471

Cited by 42 publications

(9 citation statements)

References 52 publications

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“…Usually, intermediates of this type are so unstable that they can only be characterized by NMR using special stop-flow techniques [22]. Thus, the electron-attracting CF, groups must hinder the heterolytic removal of the OH group [23] and, consequently, the carbinolamines are sufficiently stable to be isolated. However, pyrazole 1 was formed, when these partial condensation products were dehydrated by melting the reaction mixture.…”

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confidence: 99%

High‐Yield Syntheses of Sodium, Potassium, and Thallium Hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borates and the X‐ray crystal structure of {hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borato} thallium(I)

Renn¹,

Venanzi²,

Marteletti

et al. 1995

Helvetica Chimica Acta

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An improved synthesis of 3,5-bis(trifluoromethyl)pyrazole (1) is described. This compound was used for the high-yield syntheses of the tris(pyrazoly1)borates Nd[HB(3,5-(CF3),-pz),1 (2a) and the corresponding potassium salt, 2b, starting from 1 and NaBH, and KBH,, respectively. A convenient route to the corresponding thallium(1) salt, 2c, using thallium(1) acetate and either 2a or 2b in CHCI,, is also described. The sodium (3a), potasium (3b), and thallium (3c) salts of bis(pyrazoly1)borate [H,B(3,5-(CF3),-pz),]-were also prepared. The above pyrazolylborates were characterized by 'H-, I3C-, I9F-, and "B-NMR spectroscopy. The X-ray crystal structure of the thallium derivative 2c was determined. The compound crystallizes in the monoclinic space group P2,/rn with a = 8.248(9) A, b = 15.034(12)& c = 9.243(8)A,p = 100.10(7)O,Z = 2. TheTI-atomadoptsapyramidalgeometry with respect to the three N-atoms. However, two TI-N distances (2.725(7) A) are longer than the third (2.675(10) A).

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mentioning

confidence: 99%

High‐Yield Syntheses of Sodium, Potassium, and Thallium Hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borates and the X‐ray crystal structure of {hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borato} thallium(I)

Renn¹,

Venanzi²,

Marteletti

et al. 1995

Helvetica Chimica Acta

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“…In reality, the lack of 18 O-exchange simply means that protonation of the leaving group and C−N cleavage is faster than oxygen equilibration and expulsion from the tetrahedral intermediate. Due to the strong electron withdrawing properties of the CF 3 group, the starting materials are destabilized which both encourages nucleophilic addition and discourages regeneration of the amide. Thus, the rate constant for expulsion of OH from the diol may be abnormally slow.…”

Section: Discussionmentioning

confidence: 99%

Water Catalyzed Hydrolysis ofp-Nitrotrifluoroacetanilide and Trifluoroacetanilide. Carbonyl¹⁸O-Exchange Does Not Accompany the Water Reaction

et al. 1997

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The water catalyzed hydrolyses of p-nitrotrifluoroacetanilide (3) and trifluoroacetanilide (8) were studied at various pH's and temperatures. The activation parameters for the water reactions of 3 and 8 are: ΔH ⧧ = 14.4 ± 0.6 and 11.7 ± 0.3 kcal/mol and ΔS ⧧ = −36.1 ± 1.8 and −52.3 ± 0.7 cal/mol·K, respectively. These are consistent with reactions that involve considerable restriction of degrees of freedom of the solvent/substrate in the transition state. A proton inventory analysis of the rate constants for hydrolysis of 3 in media of different mole fraction D2O indicates the process involves two or more protons in flight or undergoing loosening of their bonding in the transition state. 18O-Labeled amides were subjected to the hydrolytic conditions for various times up to 3 half-times of hydrolysis and recovered. Mass analysis showed that the 18O content in the recovered amide did not change during the course of the reaction. All the data support a process where the rate-limiting step for the water reaction involves a concerted or nearly concerted formation of a diol which undergoes subsequent C−N cleavage in preference to OH expulsion.

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“…His favorite was N.P. (Tanya) Gambaryan, a brilliant research chemist [13]. By the way she was a supervisor PhD work of Quing-Yun Chen, who now is one of the leading fluorine chemists in China.…”

Section: Il Knunyants As the Lab Leadermentioning

confidence: 97%

About Ivan Ludvigovich Knunyants, Ineos, and a Little Bit About Myself

2007

Journal of Fluorine Chemistry

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Reactions of the Carbonyl Group in Fluorinated Ketones

Cited by 42 publications

References 52 publications

High‐Yield Syntheses of Sodium, Potassium, and Thallium Hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borates and the X‐ray crystal structure of {hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borato} thallium(I)

High‐Yield Syntheses of Sodium, Potassium, and Thallium Hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borates and the X‐ray crystal structure of {hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borato} thallium(I)

Water Catalyzed Hydrolysis ofp-Nitrotrifluoroacetanilide and Trifluoroacetanilide. Carbonyl¹⁸O-Exchange Does Not Accompany the Water Reaction

About Ivan Ludvigovich Knunyants, Ineos, and a Little Bit About Myself

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Reactions of the Carbonyl Group in Fluorinated Ketones

Cited by 42 publications

References 52 publications

High‐Yield Syntheses of Sodium, Potassium, and Thallium Hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borates and the X‐ray crystal structure of {hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borato} thallium(I)

High‐Yield Syntheses of Sodium, Potassium, and Thallium Hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borates and the X‐ray crystal structure of {hydrotris[3,5‐bis(trifluoromethyl)pyrazolyl]borato} thallium(I)

Water Catalyzed Hydrolysis ofp-Nitrotrifluoroacetanilide and Trifluoroacetanilide. Carbonyl18O-Exchange Does Not Accompany the Water Reaction

About Ivan Ludvigovich Knunyants, Ineos, and a Little Bit About Myself

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Water Catalyzed Hydrolysis ofp-Nitrotrifluoroacetanilide and Trifluoroacetanilide. Carbonyl¹⁸O-Exchange Does Not Accompany the Water Reaction