Transformation of 8-[(2-Hydroxyalkyl)sulfanyl]adenines to 6-Amino-7H-purin-8(9H)-one Derivatives

2001 ◽  
Vol 66 (9) ◽  
pp. 1393-1406 ◽  
Author(s):  
Zlatko Janeba ◽  
Antonín Holý ◽  
Milena Masojídková
Keyword(s):  
Hydroxy Group ◽  
Alkyl Derivative ◽  
Reaction Conditions ◽  
Derivatives Of ◽  
Adenine Derivative

Alkylation of 6-amino-7H-purin-8(9H)-thione (8-sulfanyladenine, 1) with one equivalent of (R)-[(trityloxy)methyl]oxirane gave its S-alkyl derivative 2, which was converted to the 6-amino-7H-purin-8(9H)-one (3), while alkylation of 1 with two equivalents of (S)-[(trityloxy)methyl]oxirane afforded a mixture of N3,S-dialkylated product 4a, N9-monoalkyl and N7,N9-dialkyl derivatives of 6-amino-7H-purin-8(9H)-one, 5a and 6a, respectively. This approach can be used for rapid and easy transformation of 8-[(2-hydroxyalkyl)sulfanyl]adenines to the derivatives of 6-amino-7H-purin-8(9H)-one (8-hydroxyadenine) using NaH or Cs2CO3 in DMF. The course of the S→O transformation strictly depends on the character of the starting compounds and on the reaction conditions. N9-Alkyl-8-[(2-hydroxyalkyl)sulfanyl]adenines 10, 12, 14 and 17 were rapidly converted to the corresponding 6-amino-7H-purin-8(9H)-one derivatives 11, 13, 11 and 18, respectively. N9-Unsubstituted 2 reacts slowly, and N3-alkyl derivative 4a is stable under the same reaction conditions. The described transformation does not occur when the hydroxy group in 8-[(2-hydroxyalkyl)sulfanyl]adenine derivative 15 is protected. The reaction using NaH proceeds more rapidly than that using Cs2CO3.

Cleavage of the Epimines of 1,6-Anhydrohexoses with Fluoride Anion

2005 ◽  
Vol 70 (12) ◽  
pp. 2075-2085 ◽  
Author(s):  
Jiří Kroutil ◽  
Klára Jeništová
Keyword(s):  
Fluoride Anion ◽  
Ring Cleavage ◽  
Protecting Group ◽  
Reaction Conditions ◽  
Aziridine Ring ◽  
Cleavage Reactions ◽  
Derivatives Of ◽  
Fluoro Derivatives

Aziridine ring cleavage reactions of five N-nosylepimines (2-6) having D-talo, D-galacto, D-manno, and D-allo configurations with potassium hydrogendifluoride under various reaction conditions have been performed. The cleavage regioselectively afforded diaxial isomers of vicinal amino-fluoro derivatives of 1,6-anhydro-β-D-gluco- and mannopyranose 7-11 in 51-94% yields. Removal of 2-nitrobenzenesulfonyl protecting group with benzenethiol has been attempted in the case of compound 10.

scholarly journals Enzymatic synthesis and phosphorolysis of 4(2)-thioxo- and 6(5)-azapyrimidine nucleosides by E. coli nucleoside phosphorylases

2016 ◽  
Vol 12 ◽  
pp. 2588-2601 ◽  
Author(s):  
Vladimir A Stepchenko ◽  
Anatoly I Miroshnikov ◽  
Frank Seela ◽  
Igor A Mikhailopulo
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
Reaction Conditions ◽  
E Coli ◽  
No Formation ◽  
Structural Peculiarities ◽  
Substrate Properties ◽  
Nucleoside Phosphorylases ◽  
Derivatives Of

The trans-2-deoxyribosylation of 4-thiouracil (4SUra) and 2-thiouracil (2SUra), as well as 6-azauracil, 6-azathymine and 6-aza-2-thiothymine was studied using dG and E. coli purine nucleoside phosphorylase (PNP) for the in situ generation of 2-deoxy-α-D-ribofuranose-1-phosphate (dRib-1P) followed by its coupling with the bases catalyzed by either E. coli thymidine (TP) or uridine (UP) phosphorylases. 4SUra revealed satisfactory substrate activity for UP and, unexpectedly, complete inertness for TP; no formation of 2’-deoxy-2-thiouridine (2SUd) was observed under analogous reaction conditions in the presence of UP and TP. On the contrary, 2SU, 2SUd, 4STd and 2STd are good substrates for both UP and TP; moreover, 2SU, 4STd and 2’-deoxy-5-azacytidine (Decitabine) are substrates for PNP and the phosphorolysis of the latter is reversible. Condensation of 2SUra and 5-azacytosine with dRib-1P (Ba salt) catalyzed by the accordant UP and PNP in Tris∙HCl buffer gave 2SUd and 2’-deoxy-5-azacytidine in 27% and 15% yields, respectively. 6-Azauracil and 6-azathymine showed good substrate properties for both TP and UP, whereas only TP recognizes 2-thio-6-azathymine as a substrate. 5-Phenyl and 5-tert-butyl derivatives of 6-azauracil and its 2-thioxo derivative were tested as substrates for UP and TP, and only 5-phenyl- and 5-tert-butyl-6-azauracils displayed very low substrate activity. The role of structural peculiarities and electronic properties in the substrate recognition by E. coli nucleoside phosphorylases is discussed.

Coupling of Steroid O-(Carboxymethyl)oxime Derivatives with Amino Alcohols

1996 ◽  
Vol 61 (2) ◽  
pp. 288-297 ◽  
Author(s):  
Vladimír Pouzar ◽  
Ivan Černý
Keyword(s):  
Amino Acids ◽  
Hydroxy Group ◽  
Building Blocks ◽  
Amino Alcohols ◽  
New Approach ◽  
Alternative Synthesis ◽  
Oxime Derivatives ◽  
A Chain ◽  
Derivatives Of

New approach to the preparation of steroids with connecting bridge, based on an O-carboxymethyloxime (CMO) structure, and with terminal hydroxy group, is presented. 17-CMO derivatives of 3β-acetoxy- and 3β-methoxymethoxyandrost-5-en-17-one were condensed with α,ω-amino alcohols to give derivatives with a chain of seven to nine atoms. After THP-protection, these compounds were converted to 3-keto-4-ene derivatives. An alternative synthesis consisted in transformation of 17-CMO derivatives with bonded amino acids by reduction of the terminal carboxyl. The resulting compounds were designed as building blocks for the preparation of bis-haptens for sandwich immunoassays.

Spontaneous butenolide ring formation of pregnane-21-O-malonyl hemiesters under mild reaction conditions is facilitated by the 14β-hydroxy group present in all natural cardenolides

Tetrahedron ◽  
2016 ◽  
Vol 72 (30) ◽  
pp. 4556-4563 ◽  
Author(s):  
R.M. Pádua ◽  
N. Meitinger ◽  
M. Hennemann ◽  
P. Schebitz ◽  
R. Waibel ◽  
...  
Keyword(s):  
Hydroxy Group ◽  
Ring Formation ◽  
Reaction Conditions

scholarly journals New Products Generated from the Transformations of Ferulic Acid Dilactone

Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 175 ◽  
Author(s):  
Ying He ◽  
Yuan Jia ◽  
Fachuang Lu
Keyword(s):  
Ferulic Acid ◽  
Succinic Acid ◽  
Plant Cell ◽  
Cell Walls ◽  
New Products ◽  
Plant Cell Walls ◽  
Reaction Conditions ◽  
Radical Coupling ◽  
Naoh Treatment ◽  
Derivatives Of

Various ferulic acid (FA) dimers occurring in plant cell walls, such as 8-5-, 8-O-4-, 5-5-, and 8-8-coupled dimers, are effective antioxidants and potential antimicrobials. It is necessary to access these diferulates as reference compounds to validate those isolated from plants. 3,6-bis(4-hydroxy-3-methoxyphenyl)-tetrahydrofuro-[3,4-c]furan-1,4-dione, a 8-8-coupled FA dilactone generated from ferulic acid via radical coupling, has been used to synthesize 8-8-coupled FA dimers although few reports investigated the distribution of products and mechanisms involved in the transformation of FA dilactone. In this work, the FA dilactone, obtained from FA by a peroxidase-catalyzed radical coupling, was reacted under various base/acid conditions. Effects of reaction conditions and workup procedures on the distribution of products were investigated by GC-MS. The isolated products from such treatments of FA dilactone were characterized by NMR. New derivatives of FA dimer including 2-(4-hydroxy-3-methoxybenzylidene)-3-(hydroxyl-(4-hydroxy-3-methoxyphenyl)methyl)succinic acid and 2-(bis(4-hydroxy-3-methoxyphenyl)-methyl)-succinic acid were produced from NaOH treatment. Another novel 8-8-coupled cyclic FA dimer, diethyl 6-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-7-methoxy-1,2-dihydronaphthalene-2,3-dicarboxylate was identified in products from FA dilactone treated by dry HCl in absolute ethanol. Mechanisms involved in such transformations were proposed.

Synthesis of Sterically Congested Carbamates of Carbohydrates through Organic Base Catalysis

Synthesis ◽  
2019 ◽  
Vol 51 (15) ◽  
pp. 2897-2908 ◽  
Author(s):  
Anji Chen ◽  
Dan Wang ◽  
Lalith P. Samankumara ◽  
Guijun Wang
Keyword(s):  
Hydroxy Group ◽  
Current Method ◽  
Building Blocks ◽  
Base Catalysis ◽  
Organic Base ◽  
Molecular Assemblies ◽  
Effective Catalyst ◽  
Organic Bases ◽  
Derivatives Of ◽  
General Method

4,6-O-Benzylidene acetal protected α-methoxy d-glucose and d-glucosamine are useful building blocks for the syntheses of carbohydrate derivatives and functional molecular assemblies. In this research, we have developed a general method for the preparation of C-3 carbamate derivatives of densely functionalized glucose and glucosamine with isocyanates using organic bases as catalysts. Without a suitable catalyst, the C-3 hydroxy group of the glucosamine derivative could not be converted into the corresponding carbamates when treated with isocyanates. Several organic bases were screened as the catalysts for the reactions, and we discovered that 5.0 mol% of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was an effective catalyst for the carbamoylation reaction. A library of both alkyl and aryl carbamate derivatives of the two sterically congested carbohydrates have been effectively synthesized using the current method.

scholarly journals Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

2014 ◽  
Vol 10 ◽  
pp. 1919-1932 ◽  
Author(s):  
Mahesh K Lakshman ◽  
Manish K Singh ◽  
Mukesh Kumar ◽  
Raghu Ram Chamala ◽  
Vijayender R Yedulla ◽  
...  
Keyword(s):  
Amide Bond ◽  
Coupling Agents ◽  
Cyclic Ketones ◽  
Substitution Reactions ◽  
Facile Synthesis ◽  
Reaction Conditions ◽  
Peptide Coupling ◽  
Acyclic Nucleoside ◽  
Derivatives Of

(1H-Benzo[d][1,2,3]triazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), 1H-benzo[d][1,2,3]triazol-1-yl 4-methylbenzenesulfonate (Bt-OTs), and 3H-[1,2,3]triazolo[4,5-b]pyridine-3-yl 4-methylbenzenesulfonate (At-OTs) are classically utilized in peptide synthesis for amide-bond formation. However, a previously undescribed reaction of these compounds with alcohols in the presence of a base, leads to 1-alkoxy-1H-benzo- (Bt-OR) and 7-azabenzotriazoles (At-OR). Although BOP undergoes reactions with alcohols to furnish 1-alkoxy-1H-benzotriazoles, Bt-OTs proved to be superior. Both, primary and secondary alcohols undergo reaction under generally mild reaction conditions. Correspondingly, 1-alkoxy-1H-7-azabenzotriazoles were synthesized from At-OTs. Mechanistically, there are three pathways by which these peptide-coupling agents can react with alcohols. From 31P{1H}, [18O]-labeling, and other chemical experiments, phosphonium and tosylate derivatives of alcohols seem to be intermediates. These then react with BtO− and AtO− produced in situ. In order to demonstrate broader utility, this novel reaction has been used to prepare a series of acyclic nucleoside-like compounds. Because BtO− is a nucleofuge, several Bt-OCH2Ar substrates have been evaluated in nucleophilic substitution reactions. Finally, the possible formation of Pd π–allyl complexes by departure of BtO− has been queried. Thus, alpha-allylation of three cyclic ketones was evaluated with 1-(cinnamyloxy)-1H-benzo[d][1,2,3]triazole, via in situ formation of pyrrolidine enamines and Pd catalysis.

Acetal Formation Facilitated in 2-Hydroxyaryl Aldehydes by Intramolecular Acyl Group Transfer

1986 ◽  
Vol 39 (11) ◽  
pp. 1747 ◽  
Author(s):  
AJ Liepa ◽  
AJ Liepa ◽  
TC Morton ◽  
TC Morton
Keyword(s):  
Acyl Transfer ◽  
Reaction Conditions ◽  
Group Transfer ◽  
Acetyl Group ◽  
Derivatives Of ◽  
Acyl Derivatives ◽  
Mechanism Of The Reaction

Convenient preparations of synthetically useful acetals, a dithioacetal and an oxathiolan from the 2-acyl derivatives of 2-hydroxyaryl aldehydes under basic conditions are described. The mildness of the reaction conditions is illustrated by the formation of an ethoxycarbonyl -substituted dioxolan . The reaction is dependent upon an intramolecular acetyl group transfer and the mechanism of the reaction is discussed. Some broader implications of this type of acyl transfer are discussed.

scholarly journals Catalytic Asymmetric Fluorination of Alkyl 1-indanone-2-carboxylates Ruled by Pybox-Eu(III) Combination

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1141 ◽  
Author(s):  
Albert Granados ◽  
Pau Sarró ◽  
Adelina Vallribera
Keyword(s):  
Catalytic Method ◽  
Reaction Conditions ◽  
Catalytic Asymmetric ◽  
Derivatives Of ◽  
Fluoro Derivatives

A highly enantioselective catalytic method for the synthesis of quaternary α-fluoro derivatives of 3-oxo esters is described. The reaction uses europium (III) triflate and commercially available chiral pybox-type C2-symmetric ligand. Excellent results in terms of yields and enantioselectivities were assured using the electrophilic NFSI reagent under mild reaction conditions.

Modellreaktionen zur Plumbagin-Synthese, 2. Mitteilung 5-Amino-1-naphthol als Startkomponente / Model Reactions for Plumbagin Synthesis, 2nd Communication 5-Amino-1-naphthol as Starting Compound

1987 ◽  
Vol 42 (12) ◽  
pp. 1578-1584 ◽  
Author(s):  
Hans Möhrle ◽  
Hubertus Folttmann
Keyword(s):  
Hydroxy Group ◽  
Mannich Bases ◽  
Starting Compound ◽  
Derivatives Of ◽  
Nitrosylsulfuric Acid ◽  
Model Reactions

AbstractThe aminomethylation of 5-amino-1-naphthol (1) and 5-acetamido-1-naphthol (9) is examined. While the hydrogenolysis of the phenol Mannich bases derived from 1 cannot be accomplished, the derivatives of 9 react easily. The oxidation of the 2-methylphenol compounds 5 and 18 to the corresponding quinones may performed with Fremy's salt. The following transforming of the amino to the hydroxy group by nitrosylsulfuric acid succeeds with small yield only.

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