scholarly journals The roles of hetero atoms in solvolytic reactions. III. Some evidence for preference of intramolecular catalysis by nitrogen in hydrolysis of tertiary alkyl esters.

1974 ◽  
Vol 22 (8) ◽  
pp. 1706-1710 ◽  
Author(s):  
KATSUKO UOJI ◽  
YOSHITSUGU FUKUNAGA ◽  
SHIRO IKEGAMI
Keyword(s):  
Alkyl Esters ◽  
Intramolecular Catalysis ◽  
Hydrolysis Of ◽  
Tertiary Alkyl

Synthèse de cétones encombrées via réduction de nitriles tertiaires en présence de métaux alcalins

1978 ◽  
Vol 56 (21) ◽  
pp. 2731-2736 ◽  
Author(s):  
Jean-Paul Mazaleyrat
Keyword(s):  
Radical Anion ◽  
Alkali Metals ◽  
Simple Method ◽  
Hydrolysis Of ◽  
Tertiary Alkyl

The reaction of alkali metals with tertiary alkyl nitriles eventually gives, after protonation, an imine. α-tert-Alkylketones are produced by the hydrolysis of these imines. This reaction, involving radical anion intermediates, is a simple method for the synthesis of highly hindered symmetric ketones.

ChemInform Abstract: Stereospecific Hydrolysis of Alkyl Esters by Antibodies.

ChemInform ◽  
1989 ◽  
Vol 20 (44) ◽  
Author(s):  
S. J. POLLACK ◽  
P. HSIUN ◽  
P. G. SCHULTZ
Keyword(s):  
Alkyl Esters ◽  
Hydrolysis Of

Intramolecular Catalysis of the Hydrolysis of N-Dimethylaminomaleamic Acid

Science ◽  
1963 ◽  
Vol 140 (3566) ◽  
pp. 485-486 ◽  
Author(s):  
G. Dahlgren ◽  
N. L. Simmerman
Keyword(s):  
Intramolecular Catalysis ◽  
Hydrolysis Of

Organophosphorverbindungen mit tertiären Alkylsubstituenten. III*: Synthese und Reaktionen Di-1-adamantylsubstituierter Phosphorverbindungen; Kristallstruktur von Di-1-Adamantylphosphinsäurechlorid / Organophosphorus Compounds with Tertiary Alkyl Substituents. Ill: Synthesis and Reactions of Di-1-adam antyl-Substituted Phosphorus Compounds; Crystal Structure of Di-1-adam antylphosphinic Chloride

1994 ◽  
Vol 49 (6) ◽  
pp. 801-811 ◽  
Author(s):  
Jens R. Goerlich ◽  
Axel Fischer ◽  
Peter G. Jones ◽  
Reinhard Schmutzler
Keyword(s):  
Organophosphorus Compounds ◽  
Phosphorus Compounds ◽  
Secondary Phosphine ◽  
Phosphine Oxides ◽  
X Ray ◽  
Dry Air ◽  
Nmr Data ◽  
Standard Procedures ◽  
Hydrolysis Of ◽  
Tertiary Alkyl

The reaction of adamantane with PCl3/A1Cl3, followed by hydrolysis, gave (1-Ad)2P(:O)Cl 1, which was converted to (1-Ad)2P(:O)F 2 and (1-Ad)2P(:S)Cl 3 by standard procedures. The structure of 1 was confirmed by a single crystal X-ray structure determination; despite the bulky substituents the P-C bond lengths are normal (184.0(3), 185.0(3) pm). Whereas chlorine-fluorine exchange in 3 with AsF3 furnished (1-Ad)2P(:S)F 4, desulfuration of 3 with Ph3P to give (1-Ad)2PCl 5 failed. The secondary phosphine oxides R 1R2P(:O)H (R1, R2 = 1-Ad: 6; R1 = 1-Ad, R2 = tBu: 7; R1, R2 = tBu: 8) were synthesized by reaction of 1, 1-AdP(:O)Cl2 and tBuP(:0)Cl2 with tBuLi. 6 and 8 reacted readily with chloral to give the adducts R2P(:O)CH(OH)CCl3 (R = 1-Ad: 9; R = tBu: 10). Silylation of 6 with Me2NSiMe3 in the presence of dry air led to (1-Ad)2P(:O)OSiMe3 11, which was hydrolyzed to give (1-Ad)2P(:O)OH 12. (1-Ad)2POSiMe3 13 was obtained by the reaction of 6 with n-BuLi, followed by Me3SiCl. No reaction took place upon heating 6 with Mo(CO)6. (1-Ad)2PCl 5 was synthesized in low yield by the reaction of 6 with PCl3. The action of tetrachloro-obenzoquinone (TOB) upon 6 furnished (1-Ad)2P(:O)(o-OH)C6Cl4 15, whereas the tbutyl analogue of 15, 16, was synthesized by hydrolysis of the TOB-adduct of di-tbutylfluorophosphine. Analogous 1-adamantyl- and tbutyl-phosphorus compounds are compared with regard to their 31P NMR data

Hydrolysis of aryl hydrogen maleate esters mediated by cyclodextrins — Effect on the intramolecular catalysis

2005 ◽  
Vol 83 (9) ◽  
pp. 1281-1286 ◽  
Author(s):  
Gabriel O Andrés ◽  
O Fernando Silva ◽  
Rita H de Rossi
Keyword(s):  
Maleic Anhydride ◽  
Transition State ◽  
Rate Constant ◽  
Association Constant ◽  
Kinetic Studies ◽  
Association Constants ◽  
Bulk Solution ◽  
Intramolecular Catalysis ◽  
Hydrolysis Of ◽  
Nonlinear Fashion

Kinetic studies of the hydrolysis of Z-aryl hydrogen maleates (Z = H, p-CH3, m-CH3, p-Cl, m-Cl) were carried out in the presence and absence of hydroxypropyl-β-cyclodextrin (HPCD) at variable pH from 1.00 to 3.00. The reaction involves the formation of maleic anhydride as an intermediate and the rate of its formation is strongly dependent on the pH. This is because the neighboring carboxylate group is a better catalyst than the carboxylic group. The rate constant for the formation of maleic anhydride decreases as the HPCD concentration increases in a nonlinear fashion. The results were interpreted in terms of the formation of a 1:1 inclusion complex of the esters with HPCD. The neutral (HA) and anionic (A) species of the substrate have different association constants (K[Formula: see text] and K[Formula: see text]). In all cases studied, K[Formula: see text] is higher than K[Formula: see text] for the same substrate. This difference is responsible for a decrease in the amount of the anionic substrate (reactive species) in the presence of HPCD, which results in a diminution of the observed rate constant. Besides, the rate constant for the reaction of the complexed substrate is smaller than that in the bulk solution indicating that the transition state of the cyclodextrin mediated reaction is less stabilized than the anionic substrate. The values of ΔΔG‡ are almost independent of the substituent on the aryl ring and range within 0.48 and 1.05 kcal mol–1 (1 cal = 4.184 J). There is no correlation between KTS and the association constant of the substrate indicating that the factors stabilizing the transition state are different from those that stabilize the substrate. Key words: cyclodextrins, intramolecular catalysis, hydrolysis, inhibition.

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