Synthesis of Bicyclic Pyridine Tripeptides

1994 ◽  
Vol 59 (6) ◽  
pp. 1451-1457 ◽  
Author(s):  
Abd El-Hamid Attia ◽  
Mohamed H. Abo-Ghalia ◽  
Osama I. Abd El-Salam
Keyword(s):  
Methyl Ester ◽  
Alkaline Hydrolysis ◽  
Hydrolysis Of

Dinicotinic acid reacted with L-phenylalanine affording N-dinicotinoyl-bis-L-phenylalanine (VII). The same product was also obtained by mild alkaline hydrolysis of the corresponding ester VI. Coupling of VII with L-ornithine or L-ornithine methyl ester gave rise to the formation of the desired chiral bicyclic tripeptides IIIa and IIIb as enniatin analogues.

Synthesis of potential prodrugs and metabolites of 9-(S)-(3-hydroxy-2-phosphonylmethoxypropyl)adenine

1987 ◽  
Vol 52 (11) ◽  
pp. 2792-2800 ◽  
Author(s):  
Ivan Rosenberg ◽  
Antonín Holý
Keyword(s):  
Methyl Ester ◽  
Alkaline Hydrolysis ◽  
Sodium Methoxide ◽  
Inorganic Phosphate ◽  
Cyclic Ester ◽  
Hydrolysis Of

Reaction of 9-(S)-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (I) with N,N'-dicyclohexylcarbodiimide afforded the cyclic phosphonate II. The same compound was also obtained by controlled alkaline hydrolysis of 3'-O-chloromethanephosphonyl-9-(S)-(2,3-dihydroxypropyl)adenine (III). Methanolysis of compound II or III by sodium methoxide gave methyl ester VII. Isomeric cyclic ester V and methyl ester VIII were obtained from 3'-O-phosphonylmethyl ether IV or 2'-O-chloromethanephosphonyl ester VI by the same reactions. Compound I was transformed into morpholide IX which afforded the P-diphosphoryl derivative X by treatment with inorganic diphosphate. The P-phosphoryl derivative XII was obtained from compound I by successive protection with dimethoxytrityl chloride, activation with diphenyl chlorophosphate, treatment with inorganic phosphate and acid deprotection.

Synthesis of 9-(2-phosphonylmethoxyethyl)adenine and related compounds

1987 ◽  
Vol 52 (11) ◽  
pp. 2801-2809 ◽  
Author(s):  
Antonín Holý ◽  
Ivan Rosenberg
Keyword(s):  
Methyl Ester ◽  
Ethyl Ester ◽  
Sodium Salt ◽  
Alkaline Hydrolysis ◽  
Inorganic Phosphate ◽  
Sodium Hydride ◽  
Analogous Reaction ◽  
Hydrolysis Of ◽  
Related Compounds

Diethyl 2-hydroxyethoxymethanephosphonate (VIII) was converted into diethyl 2-halogenoethoxymethanephosphonates IXa and IXb by reaction with triphenylphosphine and tetrachloromethane or tetrabromomethane; analogous reaction of VIII with p-toluenesulfonyl chloride afforded diethyl 2-(p-toluenesulfonyloxy)ethoxymethanephosphonate (IXc). Reaction of sodium salt of adenine with compounds IX led to 9-(2-diethoxyphosphonylmethoxyethyl)adenine (X). Compound X was converted into 9-(2-phosphonylmethoxyethyl)adenine (II) by treatment with bromotrimethylsilane whereas alkaline hydrolysis of X gave ethyl ester Vb. Reaction of 9-(2-hydroxyethyl)adenine (IIIa) or its N6-benzoyl derivative IIIb with dimethyl p-toluenesulfonyloxymethanephosphonate (IV) in the presence of sodium hydride, followed by alkaline hydrolysis yielded methyl ester Va. Morpholide XI reacted with an inorganic phosphate and diphosphate to give 9-(2-phosphorylphosphonylmethoxyethyl)adenine (XII) and 2-(diphosphorylphosphonylmethoxyethyl)adenine (XIII), respectively.

Influence of medium on alkaline hydrolysis of succinic acid monomethyl and monopropyl esters

1980 ◽  
Vol 45 (11) ◽  
pp. 2873-2882
Author(s):  
Vladislav Holba ◽  
Ján Benko
Keyword(s):  
Succinic Acid ◽  
Kinetic Parameters ◽  
Alkaline Hydrolysis ◽  
Specific Interactions ◽  
Nonaqueous Media ◽  
The Media ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of alkaline hydrolysis of succinic acid monomethyl and monopropyl esters were studied in mixed aqueous-nonaqueous media at various temperatures and ionic strengths. The results of measurements are discussed in terms of electrostatic and specific interactions between the reactants and other components of the reaction mixture. The kinetic parameters in the media under study are related to the influence of the cosolvent on the solvation sphere of the reactants.

Synthesis of Normuramic Acid Carba Analog and Its Glycopeptide Derivative Resistant to β-Elimination Splitting of the Side Chain

2000 ◽  
Vol 65 (11) ◽  
pp. 1726-1736 ◽  
Author(s):  
Miroslav Ledvina ◽  
Radka Pavelová ◽  
Anna Rohlenová ◽  
Jan Ježek ◽  
David Šaman
Keyword(s):  
Ethyl Ester ◽  
Alkaline Hydrolysis ◽  
Benzyl Ester ◽  
Side Chain ◽  
Propanoic Acid ◽  
Hydrolysis Of

Carba analogs of normuramic acid, i.e., 3-(benzyl 2-acetamido-2,3-dideoxy-4,6-O-isopropylidene-α-D-glucopyranosid-3-yl)propanoic acid derivatives (nitrile or esters) 3a-3c were prepared by addition of radicals generated from benzyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-3-O-[(methylsulfanyl)thiocarbonyl]- (2a) or -3-O-(phenoxythiocarbonyl)-α-D-glucopyranoside (2b) with Bu3SnH to acrylonitrile or acryl esters. Alkaline hydrolysis of ethyl ester 3c afforded 3-(benzyl 2-acetamido-2,3-dideoxy-4,6-O-isopropylidene-α-D-glucopyranosid-3-yl)propanoic acid (5). Coupling of acid 5 with L-2-aminobutanoyl-D-isoglutamine benzyl ester trifluoroacetate and subsequent deprotection of the intermediate 6 furnished N-[3-(2-acetamido-2,3-dideoxy-α-D-glucopyranosid-3-yl)propanoyl]-L-2-aminobutanoyl-D-isoglutamine (7).

Kinetic study of hydrolysis of benzoates. part xxvii. ortho substituent effect in alkaline hydrolysis of phenyl esters of substituted benzoic acids in aqueous Bu4NBr

2009 ◽  
Vol 74 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Vilve Nummert ◽  
Mare Piirsalu ◽  
Signe Vahur ◽  
Oksana Travnikova ◽  
Ilmar A. Koppel
Keyword(s):  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Pure Water ◽  
Substituent Effects ◽  
Benzoic Acids ◽  
Resonance Effects ◽  
The Media ◽  
Substituted Benzoic Acids ◽  
Hydrolysis Of ◽  
Ortho Substituent

The second-order rate constants k (in dm3 mol–1 s–1) for alkaline hydrolysis of phenyl esters of meta-, para- and ortho-substituted benzoic acids, X-C6H4CO2C6H5, have been measured spectrophotometrically in aqueous 0.5 and 2.25 M Bu4NBr at 25 °C. The substituent effects for para and meta derivatives were described using the Hammett relationship. For the ortho derivatives the Charton equation was used. For ortho-substituted esters two steric scales were involved: the EsB and the Charton steric (υ) constants. When going from pure water to aqueous 0.5 and 2.25 M Bu4NBr, the meta and para polar effects, the ortho inductive and resonance effects in alkaline hydrolysis of phenyl esters of substituted benzoic acids, became stronger nearly to the same extent as found for alkaline hydrolysis of C6H5CO2C6H4-X. The steric term of ortho-substituted esters was almost independent of the media considered. The rate constants of alkaline hydrolysis of ortho-, meta- and para-substituted phenyl benzoates (X-C6H4CO2C6H5, C6H5CO2C6H4-X) and alkyl benzoates, C6H5CO2R, in water, 0.5 and 2.25 M Bu4NBr were correlated with the corresponding IR stretching frequencies of carbonyl group, (ΔνCO)X.

Kinetic Study of Hydrolysis of Benzoates. Part XXVI. Variation of the Substituent Effect with Solvent in Alkaline Hydrolysis of Substituted Alkyl Benzoates

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1557-1570 ◽  
Author(s):  
Vilve Nummert ◽  
Mare Piirsalu ◽  
Ilmar A. Koppel
Keyword(s):  
Kinetic Study ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Substituent Effect ◽  
Substituent Effects ◽  
Alkyl Substituent ◽  
Solvent Parameters ◽  
Substituent Constants ◽  
Hydrolysis Of ◽  
Main Factor

The second-order rate constants k2 (dm3 mol-1 s-1) for the alkaline hydrolysis of substituted alkyl benzoates C6H5CO2R have been measured spectrophotometrically in aqueous 0.5 M Bu4NBr at 50 and 25 °C (R = CH3, CH2Cl, CH2CN, CH2C≡CH, CH2C6H5, CH2CH2Cl, CH2CH2OCH3, CH2CH3) and in aqueous 5.3 M NaClO4 at 25 °C (R = CH3, CH2Cl, CH2CN, CH2C≡CH). The dependence of the alkyl substituent effects on different solvent parameters was studied using the following equations:      ∆ log k = c0 + c1σI + c2EsB + c3∆E + c4∆Y + c5∆P + c6∆EσI + c7∆YσI + c8∆PσI     ∆ log k = c0 + c1σ* + c2EsB + c3∆E + c4∆Y + c5∆P + c6∆Eσ* + c7∆Yσ* + c8∆Pσ* .  ∆ log k = log kR - log kCH3. σI and σ* are the Taft inductive and polar substituent constants. E, Y and P are the solvent electrophilicity, polarity and polarizability parameters, respectively. In the data treatment ∆E = ES - EH2O , ∆Y = YS - YH2O , ∆P = PS - PH2O were used. The solvent electrophilicity, E, was found to be the main factor responsible for changes in alkyl substituent effects with medium. When σI constants were used, variation of the polar term of alkyl substituents with the solvent electrophilicity E was found to be similar to that observed earlier for meta and para substituents, but twice less when σ* constants were used. The steric term for alkyl substituents was approximately independent of the solvent parameters.

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