Ribonucleosides of 3-amino- and 3,5-diaminopyrazole-4-carboxylic acid and their open-chain analogues: Synthesis and reactions

1986 ◽  
Vol 51 (7) ◽  
pp. 1512-1531 ◽  
Author(s):  
Maria K. Spassova ◽  
Antonín Holý ◽  
Milena Masojídková
Keyword(s):  
Carboxylic Acid ◽  
Acid Hydrolysis ◽  
Carboxylic Acids ◽  
Sodium Salt ◽  
Alkaline Hydrolysis ◽  
Trimethylsilyl Derivative ◽  
Open Chain ◽  
Silyl Derivatives ◽  
Hydrolysis Of

Bis(trimethylsilyl) derivative of ethyl 3-aminopyrazole-4-carboxylate (VI) and tris(trimethylsilyl) derivative of ethyl 3,5-diaminopyrazole-4-carboxylate (VII) on reaction with 2,3,5-tri-O-benzoyl-D-ribofuranolyl chloride and subsequent debenzoylation afforded the respective β-D-ribofuranosyl derivatives VIIIa and Xa. Their alkaline hydrolysis led to 1-(β-D-ribofuranosyl)-3-aminopyrazole-4-carboxylic acid (VIIIc) and 1-(β-D-ribofuranosyl)-3,5-diaminopyrazole-4-carboxylic acid (Xb). The esters VIIIa and Xa were not ammonolyzed under normal conditions. Contrary to nucleosidation of the silyl derivatives VI and VII, sodium salt of ethyl 3-aminopyrazole-4-carboxylate was alkylated with 4-chloromethyl-2,2-dimethyl-1,3-dioxolane (XI) or 5-(p-toluenesulfonyloxy)-1,3-dioxane (XVIIb) to give a mixture of the N-isomeric derivatives XIIIa, XIXa and XIIa, XVIIIa, respectively; sodium salt of the 3,5-diamino derivative V reacted with these synthons under formation of the corresponding compounds XIIIb and XXa. Subsequent alkaline and acid hydrolysis of XIIa and XIIIb gave the open-chain analogs of nucleosides XV and XVI. The N-(1,3-dioxan-5-yl) derivatives XVIIIc and XXa resisted acid hydrolysis, giving rise only to carboxylic acids XVIIIb and XXb.

Isocarbostyrils. II. The Conversion of 2-Methyl-4-acyl-5-nitroisocarbostyrils to 2-Substituted Indole-4-carboxylic Acids

1971 ◽  
Vol 49 (17) ◽  
pp. 2797-2802 ◽  
Author(s):  
D. E. Horning ◽  
G. Lacasse ◽  
J. M. Muchowski
Keyword(s):  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Alkaline Hydrolysis ◽  
Mannich Reaction ◽  
Reductive Cyclization ◽  
Acid Catalyzed ◽  
Acid Anhydrides ◽  
Hydrolysis Of ◽  
Derivatives Of

The sulfuric acid catalyzed acylation of 2-methyl-5-nitroisocarbostyril with carboxylic acid anhydrides gave the corresponding 4-acylated derivatives 3, which underwent reductive cyclization to 2-substituted derivatives of 4-methyl-1,3,4,5-tetrahydropyrrolo[4.3.2.de]isoquinolin-5-one (4). Alkaline hydrolysis of the six-membered lactam in 4 was accompanied by a retro-Mannich reaction to produce 2-substituted indole-4-carboxylic acids in about 40 % overall yield from 3.

Kinetic Study of Hydrolysis of Benzoates. Part XXV. Ortho Substituent Effect in Alkaline Hydrolysis of Phenyl Esters of Substituted Benzoic Acids in Water

2006 ◽  
Vol 71 (1) ◽  
pp. 107-128 ◽  
Author(s):  
Vilve Nummert ◽  
Mare Piirsalu ◽  
Vahur Mäemets ◽  
Ilmar Koppel
Keyword(s):  
Acid Hydrolysis ◽  
Alkaline Hydrolysis ◽  
Substituent Effect ◽  
Ethyl Esters ◽  
Benzoic Acids ◽  
Neat Water ◽  
Substituted Benzoic Acids ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

The second-order rate constants k2 for alkaline hydrolysis of phenyl esters of meta-, para- and ortho-substituted benzoic acids, X-C6H4CO2C6H5 (X = H, 3-Cl, 3-NO2, 3-CH3, 4-NO2, 4-Cl, 4-F, 4-CH3, 4-OCH3, 4-NH2, 2-NO2, 2-CN, 2-F, 2-Cl, 2-Br, 2-I, 2-CH3, 2-OCH3, 2-CF3, 2-NH2), and of substituted phenyl esters of benzoic acid, C6H5CO2C6H4-X (X = 2-I, 2-CF3, 2-C(CH3)3, 4-Cl, 4-CH3, 4-OCH3, 4-NH2), have been measured spectrophotometrically in water at 25 °C. The substituent effect in alkaline hydrolysis of phenyl esters of para-substituted benzoic acids, similar to that for ethyl esters of para-substituted benzoic acids, was found to be precisely described by the Hammett relationship (ρ = 1.7 in water). The log k value for alkaline hydrolysis of phenyl and ethyl esters of meta-, para- and ortho-substituted benzoic acids, X-C6H4CO2R, was nicely correlated with log km,p,ortho = log ko + (ρ)m,pσ + (ρI)orthoσI + (ρ°R)orthoσ°R + δorthoEsB where σ, σI, σ°R are the Hammett polar, Taft inductive and Taft resonance (σ°R = σ° - σI) substituent constants, respectively. EsB is the steric scale for ortho substituents calculated on the basis of the log k values for the acid hydrolysis of ortho- substituted phenyl benzoates in water owing to the ortho substituent in the phenyl of phenyl benzoates. In water, the main factors responsible for changes in the ortho substituent effect in alkaline hydrolysis of phenyl and ethyl esters of ortho-substituted benzoic acids, X-C6H4CO2R, were found to be the inductive and steric factors while the role of the resonance term was negligible ((ρ°R)ortho ca. 0.3). In alkaline hydrolysis of substituted benzoates in neat water, the ortho inductive effect appeared to be 1.5 times and steric influence 2.7 times higher than the corresponding influences from the ortho position in the phenyl of phenyl benzoates. The contributions of the steric effects in alkaline hydrolysis of esters of ortho-substituted benzoic acids was found to be approximately the same as in acid hydrolysis of esters of ortho-substituted benzoic and acid esterification of ortho-substituted benzoic acids.

scholarly journals The formation of lipid-linked sugars by cell-free preparations of lactating rabbit mammary gland

1978 ◽  
Vol 170 (3) ◽  
pp. 479-486 ◽  
Author(s):  
D A White
Keyword(s):  
Mammary Gland ◽  
Acid Hydrolysis ◽  
Alkaline Hydrolysis ◽  
Gel Electrophoresis ◽  
Incubation Medium ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein Fractions ◽  
Exogenous Substrate ◽  
Major Species ◽  
Hydrolysis Of

1. A lactating rabbit mammary-gland microsomal system catalysed the incorporation of mannose from GDP-[U-14C]mannose into three endogenous acceptors, (i) polyprenyl phosphate mannose, (ii) lipid-linked oligosaccharide and (iii) protein. 2. Synthesis of polyprenyl phosphate mannose was stimulated by addition of dolichol phosphate to the incubation medium and was reversed by addition of GDP. The product had properties identical with those of authentic dolichol phosphate mannose. 3. The oligosaccharides derived from acid hydrolysis of the lipid-linked oligosaccharide fraction were of six, eight and nine to ten monosaccharide units, the octasaccharide being the major species formed. The oligosaccharide appeared to be attached to the lipid via a pyrophosphate bridge, since strong alkaline hydrolysis liberated an oligosaccharide phosphate. 4. Polyprenyl phosphate mannose served as a mannose donor to lipid-linked oligosaccharides and protein. When added as exogenous substrate it gave rise to a lipid-linked oligosaccharide of about six units. 5. Incorporation of radioactivity in protein was low, but polyacrylamide-gel electrophoresis of the protein fractions indicated that polypeptides of mol.wts. 115000, 75000 and 33000 were labelled.

Synthesis of 3-amino- and 3-azidoanalogs of 9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA)

1989 ◽  
Vol 54 (2) ◽  
pp. 446-454 ◽  
Author(s):  
Antonín Holý
Keyword(s):  
Acid Hydrolysis ◽  
Sodium Salt ◽  
Catalytic Hydrogenation ◽  
Alkaline Hydrolysis ◽  
Benzoyl Chloride ◽  
Sodium Hydride ◽  
Acid Catalyzed ◽  
Excess Sodium ◽  
Chloride Treatment

1-Azidopropane-2,3-diol (IIb) reacts with p-toluenesulfonyl chloride to give the tosyl derivative IIIa which, on acid catalyzed condensation with 2,3-dihydropyran, afforded 1-azido-2-(tetrahydropyran-2-yloxy-3-(p-toluenesulfonyloxy)propane (IIIb). Treatment of adenine sodium salt with IIIb resulted in the intermediate IV which was transformed by acid hydrolysis to 9-(RS)-(3-azido-2-hydroxypropyl)adenine (V). Catalytic hydrogenation of V led to 9-(RS)-(3-amino-2-hydroxypropyl)adenine (VI). 9-(RS)-(3-Azido-2-hydroxypropyl)-N6-benzoyladenine (VII) was obtained from V by chlorotrimethylsilane/benzoyl chloride treatment. Reaction of the compound VII with dimethyl p-toluenesulfonyloxymethanephosphonate (VIII) in the presence of excess sodium hydride, followed by alkaline hydrolysis, afforded methyl 9-(3-azido-2-phosphonylmethoxypropyl)adenine (IXa) which was transformed to the parent acid IXb by bromotrimethylsilane treatment. Hydrogenolysis of IXb yielded 9-(RS)-(3-amino-2-phosphonylmethoxypropyl)adenine (X).

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