Acid-catalyzed migration of N4-acyl groups in cytosine derivatives

1979 ◽  
Vol 44 (6) ◽  
pp. 1819-1827 ◽  
Author(s):  
Antonín Holý
Keyword(s):  
Acetic Acid ◽  
Trifluoroacetic Acid ◽  
The Other ◽  
Aqueous Acetic Acid ◽  
Amino Group ◽  
Benzoyl Group ◽  
Benzoyl Cyanide ◽  
Acid Catalyzed ◽  
Derivatives Of ◽  
Anhydrous Acetic Acid

Heating 1-(2,3-di-O-benzoyl-β-D-arabinofuranosyl)-N4-benzoylcytosine (I) in 80% acetic acid afforded 1-(2,3-di-O-benzoyl-β-D-arabinofuranosyl)-N3-benzoylcytosine (II). Benzoylation of 5'-O-tritylcytidine (V) led to the 2',3',N4-tribenzoyl derivative VI which was refluxed with 80% acetic acid to give 2',3',N3-tribenzoylcytidine (VII). Analogously, 2',3',5',N4-tetrabenzoylcytidine (IX), prepared by benzoylation of cytidine with benzoyl cyanide, gave on reflux with 80% acetic acid 2',3',5',N3-tetrabenzoylcytidine (X). Under identical conditions, 1-methyl-N4-benzoylcytosine (XI) afforded directly 1-methyluracil (XII) .This migration takes place also in acetyl derivatives of cytosine nucleosides: 2',3',5',N4-tetraacetylcytidine (XIII) was transformed to the N3-acetylcytosine derivative XIV. On the other hand, migration of acetyl or benzoyl group from the exo-amino group of adenine has not been observed under the mentioned conditions. The migration of the N4-acyl group of cytosine derivatives proceeds best in aqueous acetic acid, more slowly also in anhydrous acetic acid, but not by action of trifluoroacetic acid in 1,2-dichloroethane.

Organic sulfur compounds. VII. Some reactions of benzothiazine hydroxamic acids

1970 ◽  
Vol 48 (23) ◽  
pp. 3727-3732 ◽  
Author(s):  
R. T. Coutts ◽  
Sharon J. Matthias ◽  
E. Mah ◽  
N. J. Pound
Keyword(s):  
Acetic Acid ◽  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Unsaturated Acid ◽  
Hydroxamic Acids ◽  
Sulfur Compounds ◽  
The Other ◽  
Complex Reaction ◽  
Organic Sulfur Compounds ◽  
Derivatives Of

Treatment of (3,4-dihydro-4-hydroxy-3-oxo-2H-1,4-benzothiazin-2-yl)acetic acid (1a) with sodium hydroxide yields the corresponding lactam, i.e. (3,4-dihydro-3-oxo-2H-1,4-benzothiazin-2-yl)acetic acid, together with the α,β-unsaturated acid, 3,4-dihydro-3-oxo-2H-1,4-benzothiazine-Δ2,α-acetic acid. The 6-methyl- and 6-bromo-derivatives of 1a behaved similarly when reacted with sodium hydroxide but when 3,4-dihydro-4-hydroxy-3-oxo-2H-1,4-benzothiazine was so treated a more complex reaction occurred.Methyl (6-bromo-3,4-dihydro-4-hydroxy-3-oxo-2H-1,4-benzothiazin-2-yl)acetate was also treated with hydrochloric acid. The two products isolated were (6-bromo-3,4-dihydro-3-oxo-2H-1,4-benzothiazin-2-yl)acetic acid and (6-bromo-7-chloro-3,4-dihydro-3-oxo-2H-1,4-benzothiazin-2-yl)acetic acid.The action of hydrochloric acid on 3,4-dihydro-4-hydroxy-7-methyl-3-oxo-2H-1,4-benzothiazine also gave two products. One was the corresponding lactam; the other was unexpected and has been tentatively identified as bis[2-(3,4-dihydro-7-methyl-3-oxo-2H-1,4-benzothiazine].

Oxidation of α-Hydroxy Acids with Quinolinium Dichromate - A Kinetic Study

1993 ◽  
Vol 58 (7) ◽  
pp. 1624-1630 ◽  
Author(s):  
Kailasa Aruna ◽  
Prerepa Manikyamba ◽  
Embar Venkatachari Sundaram
Keyword(s):  
Dielectric Constant ◽  
Acetic Acid ◽  
Bond Cleavage ◽  
Low Dielectric Constant ◽  
Aqueous Acetic Acid ◽  
Hydroxy Acids ◽  
First Order ◽  
Low Dielectric ◽  
Chloro Derivative ◽  
Acid Catalyzed

Oxidation of lactic acid, α-hydroxyphenyllacetic acid and its 4-chloro derivative with quinolinium dichromate (QDC) in 30% (v/v) aqueous acetic acid at 303 K are first order in QDC and first-order in hydroxy acids. The reactions are acid-catalyzed and a medium of low dielectric constant favours the oxidation. The products are the corresponding aldehydes. Thermodynamic parameters are evaluated and a mechanism involving a C-C bond cleavage is proposed.

scholarly journals Oxidation of tissue polysaccharides by periodic acid in dimethyl sulfoxide and its anhydrous and aqueous mixtures.

1977 ◽  
Vol 25 (3) ◽  
pp. 188-192 ◽  
Author(s):  
G I Malinin
Keyword(s):  
Acetic Acid ◽  
Dimethyl Sulfoxide ◽  
Periodic Acid ◽  
Periodate Oxidation ◽  
Polarized Light ◽  
Aqueous Mixtures ◽  
Selective Localization ◽  
Schiff Reaction ◽  
Derivatives Of ◽  
Anhydrous Acetic Acid

Periodic acid (1% w/v) solvated by anhydrous dimethyl sulfoxide (DMSO) readily induced a strong Schiff reaction in a variety of structures containing polysaccharides, but not glycogen. With the increasing amounts of water added to DMSO, glycogen was also oxidized, while the selective localization of other polysaccharides remained unimpaired. Periodate, solvated in the anhydrous acetic acid-DMSO mixture, rapidly induced concomitant oxidation of nucin and glycogen-containing structures. Sodium bisulfite addition derivatives of carbonyls, induced by periodate oxidation in DMSO, were stained meta- and orthochromatically with toluidine blue at controlled pH. Certain metachromatic tissue components were strongly birefringent in polarized light in contrast to the identical structures oxidized by aqueous periodate. Marked differences in staining reactions elicited in identical structures by periodate in DMSO as compared with aqueous periodate suggest that DMSO-periodate method considerably enhances the range of histochemical oxidations by periodate.

scholarly journals Antioxidant activity of some coumarins / Antioxidačná activita niektorých kumarínov

2015 ◽  
Vol 62 (s9) ◽  
pp. 41-45 ◽  
Author(s):  
F. Šeršeň ◽  
M. Lácová
Keyword(s):  
Antioxidant Activity ◽  
Acetic Acid ◽  
Superoxide Anion ◽  
The Other ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Coumarin Derivatives ◽  
Antioxidant Effectiveness ◽  
Derivatives Of ◽  
Superoxide Anion Radicals

AbstractNineteen derivatives of coumarin were tested on the scavenging of 2,2-diphenyl-1-picrylhydrazyl, hydroxyl and superoxide anion radicals. It was found that antioxidant activity exhibits only such coumarins that contain hydroxyl groups. The derivatives without hydroxyl group showed very low antioxidant effectiveness or they were ineffective. On the other hand, the greatest antioxidant effectiveness was exhibited by coumarin derivatives that contained hydroxyl groups in 6 or 8 position, whereas the effectiveness of derivatives with one hydroxyl group in 4, 5 or 7 position was very low. Based on scavenging of the above-mentioned radicals, it was found that the most effective scavengers were 7,8-dihydroxy-4-methylcoumarin (i.e. compound that contains two hydroxyl groups in 7 and 8 positions), (7,8-dihydroxy-2-oxo-2H-chromen-4-yl)acetic acid (this compound contains in addition to two hydroxyl groups in 7 and 8 positions also one hydroxyl group in the acidic residue), esculetin (6,7-dihydroxycoumarin) and 6,7-dihydroxy-4-methylcoumarin.

Synthesis of 1,2,4-triazine-3,5(2H,4H)-diones containing electronegative substituents in position 6

1983 ◽  
Vol 48 (9) ◽  
pp. 2676-2681 ◽  
Author(s):  
Jiří Farkaš
Keyword(s):  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Nitro Compound ◽  
Trifluoroacetic Acid ◽  
Acid Synthesis ◽  
Amino Derivative ◽  
Effect Of Substituents ◽  
Fluoro Derivative ◽  
Cuprous Cyanide ◽  
Derivatives Of

Reaction of fluorine with 1,2,4-triazine-3,5(2H,4H)-dione (I) in acetic acid afforded the 6-fluoro derivative II in low yield. The 6-nitro compound III was prepared by oxidation of the 6-amino derivative of compound I with hydrogen peroxide in trifluoroacetic acid. Synthesis of the 6-cyano compound IV was accomplished by treatment of the 6-bromo derivative with cuprous cyanide in N,N,N',N'-tetramethylurea. The effect of substituents on the carbonyl frequencies for 6-substituted derivatives of I was studied.

The pyridinium–dihydropyridine system. I. Synthesis of a series of substituted pyridinium ions and their 1,4-dihydro reduction products and a determination of their stabilities in aqueous buffers

1977 ◽  
Vol 55 (10) ◽  
pp. 1687-1695 ◽  
Author(s):  
Donald J. Norris ◽  
Ross Stewart
Keyword(s):  
Acetic Acid ◽  
Acidic Solution ◽  
Buffer System ◽  
Pyridinium Salts ◽  
Acetyl Group ◽  
Acid Catalyzed ◽  
Derivatives Of ◽  
Rate Controlling Step ◽  
Pyridinium Ions

Fourteen pyridinium salts, substituted at the 1- and 3-positions, have been prepared and their stabilities determined in aqueous acetate and tris(hydroxymethyl)aminomethane (Tris) buffers. The 1,4-dihydro derivatives of eleven of these have been prepared and characterized and their stabilities likewise determined. The pyridinium ions are stable in acidic solution but undergo either ring attack or amide or ester hydrolysis under basic conditions, whereas the dihydropyridines undergo covalent hydration in acid solution. For only four pairs of compounds and one buffer system (Tris) are there pH-ranges in which the pyridinium and dihydropyridine forms are simultaneously stable (less than 10% decomposition in 24 h). These compounds have a carbamoyl or acetyl group at the 3-position and either a methoxymethyl, acetonyl, or carbamoylmethyl group at the 1-position. The acetic acid catalyzed rates of hydration of the 1-alkyl-3-carbamoyl-1,4-dihydropyridines are correlated by σ* values with a ρ* of −2.00, consistent with protonation being the rate-controlling step.

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