Synthesis of N4-Amino and N4-Hydroxy Derivatives of 5-Azacytidine. A Facile Rearrangement of the N4-Amino Derivative to 5-(3-β-D-Ribofuranosylureido)-1H-1,2,4-triazole

2004 ◽  
Vol 69 (4) ◽  
pp. 905-917 ◽  
Author(s):  
Alois Pískala ◽  
Naeem B. Hanna ◽  
Milena Masojídková ◽  
Pavel Fiedler ◽  
Ivan Votruba
Keyword(s):  
Acid Hydrolysis ◽  
Alkaline Hydrolysis ◽  
Hydroxylamine Hydrochloride ◽  
Amino Derivative ◽  
Cytostatic Activity ◽  
Thermal Rearrangement ◽  
Water Solutions ◽  
Hydrolysis Of ◽  
Derivatives Of

Treatment of methoxyribosyltriazinone 4 with hydrazine in methanol afforded crude 4-hydrazino-1-β-D-ribofuranosyl-1,3,5-triazin-2(1H)-one (N4-amino-5-azacytidine) (2), which rearranged rapidly to isomeric 5-ribosylureidotriazole 6. The rearrangement proceeds easily also in water solutions of 2. Alkaline hydrolysis of 6 gave a mixture of 5-ureidotriazole 7 and 5-aminotriazole 8. Acid hydrolysis of 6 afforded only 7. This compound was also prepared by thermal rearrangement of 5-amino-1-carbamoyltriazole 9 or on reaction of cyano(formyl)guanidine 10 with hydrazine hydrochloride. Treatment of benzoylated methoxyribosyltriazinone 4a with hydrazine in methanol gave only the rearranged product 6a. Reaction of tribenzoylribosyl isocyanate 12 with aminotriazole 8 gave 1-triazolecarboxamidotribenzoylribose 13, which afforded by methanolysis oxazoloribofuranose 14 and aminotriazole 8. Compound 14 was also obtained by methanolysis of blocked ribosylcarbamate 16. Reaction of methoxyribosyltriazinone 4 with hydroxylamine in methanol afforded 4-hydroxylamino-1-β-D-ribofuranosyl-1,3,5-triazin-2(1H)-one (N4-hydroxy-5-azacytidine) (3), which on the action of excess hydroxylamine yielded 1-cyano-1-hydroxy-5-β-D-ribofuranosylisobiuret (19). Treatment of methoxy-1,3,5-triazinone 18 with a solution of hydroxylamine in methanol gave 4-hydroxylamino-1-methyl-1,3,5-triazin-2(1H)-one (N4-hydroxy-1-methyl-5-azacytosine) (17). Heating of cyano(formyl)guanidine 10 with hydroxylamine hydrochloride in water lead to the formation of triuret (21). The mechanisms of the reactions of methoxyribosyltriazinone 4 with hydrazine and hydroxylamine are discussed. Compounds 2, 6 and 19 exhibited no significant antibacterial or cytostatic activity.

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.

The Chemical Evolution of a Nitrogenase Model, 20 Alkyl Molybdates(VI) and the Mechanism of Hydrocarbon Production by Nitrogenase [1]

1982 ◽  
Vol 37 (3) ◽  
pp. 380-385 ◽  
Author(s):  
G. N. Schrauzer ◽  
Laura A. Hughes ◽  
Norman Strampach
Keyword(s):  
Aqueous Solution ◽  
Alkaline Hydrolysis ◽  
Room Temperature ◽  
Bond Cleavage ◽  
Model Compounds ◽  
Hydrocarbon Production ◽  
Acidic Solutions ◽  
Reducing Conditions ◽  
Hydrolysis Of ◽  
Derivatives Of

Abstract Colorless alkylmolybdates(VI) of composition R-MoO3-are generated in aqueous solutions by the alkaline hydrolysis of complexes R-Mo(Bpy)(0)2Br(Bpy = 2,2′-bipyridyl, R = CH3 and higher alkyl). At room temperature in alkaline aqueous solution, the new organometallic derivatives of oxomolybdate(VI) are remarkably resistant against Mo-C bond hydrolysis. Decomposition occurs more rapidly on heating, affording unrearranged alkanes according to the eq.: R-MoO3- + OH-→RH + Mo04=. In acidic solutions, the methylmolybdate(VI) species decomposes with the formation of a mixture of methane and ethane while higher alkylmolybdates carrying hydrogen in the β-position relative to molybdenum undergo Mo-C bond heterolysis by way of β-elimina-tion: R-CH2CH2-MoO3 → Mo+4 (aq) + H+ + R-CH = CH2. The Mo-C bond of alkylmolybdates is resistant to oxidants but is very sensitive to cleavage under reducing conditions. Reductive Mo-C bond cleavage occurs particularly rapidly in the presence of thiols and reduced ferredoxin model compounds. The latter reactions simulate the terminal steps of hydrocarbon producing reactions of nitrogenase with alternate substrates such as CN-, R-CN or R-NC, confirming previous mechanistic conclusions concerning the mechanism of nitrogenase action.

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.

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.

1'-Derivatives of sucrose and their acid hydrolysis

1980 ◽  
Vol 33 (11) ◽  
pp. 2487 ◽  
Author(s):  
RD Guthrie ◽  
ID Jenkins ◽  
JJ Watters
Keyword(s):  
Acid Hydrolysis ◽  
Hydrolysis Of ◽  
Derivatives Of

Syntheses of 1'-chloro-1'-deoxy- and 1'-deoxy-sucrose are described. Several routes were investigated, the most successful being through 6,1',6'-tri-O-(2,4,6-trimethylbenzenesulfonyl)sucrose. Attempts to prepare 1'-deoxy-1'-fluorosucrose were unsuccessful. The rates of the acid-catalysed hydrolysis of 1'-chloro-1'-deoxysucrose and of 1'- deoxysucrose have been measured. These values are compared with that for sucrose itself. The mechanism of the hydrolyses is discussed.

ChemInform Abstract: KINETICS OF THE ACID HYDROLYSIS OF VINYL DERIVATIVES OF BENZIMIDAZOLE-2-THIONE, BENZOXAZOL-2-ONE AND -2-THIONE

1983 ◽  
Vol 14 (17) ◽  
Author(s):  
L. I. SVYATKINA ◽  
N. D. ABRAMOVA ◽  
L. L. DMITRIEVA ◽  
B. V. TRZHTSINSKAYA ◽  
G. G. SKVORTSOVA
Keyword(s):  
Acid Hydrolysis ◽  
Vinyl Derivatives ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Derivatives Of

Acid hydrolysis of N-methyl derivatives of 4-phenyl-5-oxo-4,5-dehydroindeno[1,2-b]pyridine

1986 ◽  
Vol 22 (10) ◽  
pp. 1104-1107 ◽  
Author(s):  
V. K. Lusis ◽  
D. Kh. Mutsenietse ◽  
G. Ya. Dubur
Keyword(s):  
Acid Hydrolysis ◽  
Methyl Derivatives ◽  
Hydrolysis Of ◽  
Derivatives Of
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