Nucleic acid related compounds. 66. Improved syntheses of 5′-chloro-5′-deoxy- and 5′-S-aryl(or alkyl)-5′-thionucleosides

1991 ◽  
Vol 69 (9) ◽  
pp. 1468-1474 ◽  
Author(s):  
Morris J. Robins ◽  
Fritz Hansske ◽  
Stanislaw F. Wnuk ◽  
Tadashi Kanai
Keyword(s):  
Ambient Temperature ◽  
Thionyl Chloride ◽  
Hydroxyl Group ◽  
Key Words Adenosine ◽  
Nucleophilic Displacement ◽  
Cyclic Sulfite ◽  
High Yields ◽  
Work Up ◽  
Related Compounds ◽  
Methanolic Ammonia

Treatment of ribonucleosides with thionyl chloride/pyridine/acetonitrile (0 °C to ambient temperature) resulted in essentially quantitative formation of 5′-chloro-5′-deoxy-2′,3′-O-sulfinylnucleoside derivatives. These diastereomeric sulfite esters underwent deprotection readily with aqueous methanolic ammonia. This gave 5′-chloro-5′-deoxynucleosides without use of the suspected carcinogen, hexamethylphosphoramide (HMPA). Nucleophilic displacement with sodium thiolates in dimethylformamide (−30 °C to ambient temperature) gave 5′-S-aryl(or alkyl)-5′-thionucleosides in high yields. Treatment of ribonucleosides with thionyl chloride/acetonitrile without pyridine followed by aqueous work-up gave diastereomeric 2′,3′-O-sulfinylnucleosides with an unmodified 5′-hydroxyl group. Diagnostic NMR shifts for cyclic sulfite ester stereochemistry are noted. Key words: adenosine, 5′-S-aryl(or alkyl)-5′-thionucleosides, 5′-chloro-5′-deoxynucleosides, uridine, nucleosides.

Nucleic acid related compounds. 63. Synthesis of 5′-deoxy-5′-methyleneadenosine and related Wittig-extended nucleosides

1991 ◽  
Vol 69 (2) ◽  
pp. 334-338 ◽  
Author(s):  
Stanislaw F. Wnuk ◽  
Morris J. Robins
Keyword(s):  
Nucleic Acid ◽  
Key Words ◽  
Organic Bases ◽  
Key Words Adenosine ◽  
Tosyl Group ◽  
High Yields ◽  
Related Compounds

Treatment of the purified 5′-aldehyde (2a) (derived from 6-N-benzoyl-2′,3′-O-isopropylideneadenosine (1a)) with methylenetriphenylphosphorane and successive deprotection with ammonia and acid gave 9-(5,6-dideoxy-β-D-ribo-hex-5-enofuranosyl)adenine (5′-deoxy-5′-methyleneadenosine) (4). Oxidation of 1a or 2′,3′-O-isopropylideneadenosine (1b) and treatment of the crude 5′-aldehydes (2a or 2b) with (p-toluenesulfonylmethylene)triphenylphosphorane gave high yields of the 5′-deoxy-5′-tosylmethylene derivatives (5a or 5b). Removal of the tosyl group from 5b to give 3b was effected with tributylstannyllithium, but sulfone cleavage by the usual reductive methods failed. Reduction and deprotection of 5a or 5b gave 9-[5,6-dideoxy-6-(p-toluenesulfonyl)-β-D-ribo-hexofuranosyl]adenine (6b). Isomerization of the vinyl tosyl (5b) to a 4′,5′-unsaturated allylic tosyl derivative (7) occurred under cleavage conditions and in solutions of aqueous or organic bases. Key words: adenosine, 5′-deoxyadenosine, 5′-methylene-5′-deoxyadenosine, nucleosides.

Nucleic acid related compounds. 29. Thionyl chloride reactions with adenine nucleosides. Course of nucleophilic displacements and a preferential route to the 2′-chloro-arabino isomer

1979 ◽  
Vol 57 (3) ◽  
pp. 274-282 ◽  
Author(s):  
Morris J. Robins ◽  
Peter Sporns ◽  
Wolfgang H. Muhs
Keyword(s):  
Nucleic Acid ◽  
Thionyl Chloride ◽  
Nucleophilic Displacement ◽  
Related Compounds

A multistage sequence gave 5′-O-pivalyl-3′-O-methyladenosine (2e) which was treated with thionyl chloride in hot pyridine to give the corresponding 2'-chloro-arabino product 3a. Hydrogenolysis using tri-n-butyltin hydride and deblocking gave 2′-deoxy-3′-O-methyl-adenosine (3b). Analogous treatment of a mixture of 3′(2′),5′-di-O-acetyladenosines (5a,b) with SOCl2-pyridine gave the 3′-O-acetyl-2′-chloro-arabino (6a) and 2′-O-acetyl-3′-chloro-xylo (7a) derivatives in a ratio of ∼3:2, respectively. Hydrogenolysis and deprotection gave 2′-deoxyadenosine (6c) and 3′-deoxyadenosine (7c) (∼3:2) in ∼45% overall yield from adenosine (based on recovered starting materials). This represents the first example of preferential external nucleophilic displacement at C-2′ (vs. C-3′) in an equilibrating purine ribonucleoside system. Treatment of 9-β-D-xylofuranosyladenine (9) with SOCl2–HMPA gave the 5′-chloro-5′-deoxy product 10a rather than the previously suggested 2′-chloro-2′-deoxy derivative.

scholarly journals An efficient and practical chemo-enzymatic route to (3R,3aR,6R,6aR)-hexahydrofuro[3,2-b]furan-6-amino-3-ol (6-aminoisomannide) from renewable sources

SynOpen ◽  
2021 ◽  
Author(s):  
Valerio Zullo ◽  
Antonella Petri ◽  
Anna Iuliano
Keyword(s):  
Hydroxy Group ◽  
Sodium Azide ◽  
Hydroxyl Group ◽  
Azido Group ◽  
One Pot ◽  
Renewable Sources ◽  
Nucleophilic Displacement ◽  
Trifluoromethanesulfonic Anhydride ◽  
Enzymatic Route

The synthesis of 6-aminoisomannide is easily achieved starting from the renewable, inexpensive and commercially available isosorbide, in 66% overall yield. A biocatalysed highly regioselective acetylation of the 3-endo hydroxyl group of isosorbide was followed by the stereospecific interconversion of the 6-exo hydroxyl group into azido group, through reaction with trifluoromethanesulfonic anhydride followed by nucleophilic displacement of the triflate group by sodium azide. Finally, reduction of the azido group and deacetylation of the 3-hydroxy group were performed one pot by using LiAlH4.

Ultrasound-assisted aqua-mediated synthesis of multi-substituted tetrahydropyridine-3-carboxylates using N-carboxymethyl-3-pyridinium hydrogensulfate ([N-CH2CO2H-3-pic]+HSO4−) as a new efficient ionic liquid catalyst

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Kobra Nikoofar ◽  
Fatemeh Shahriyari
Keyword(s):  
Ionic Liquid ◽  
Reaction Times ◽  
Aromatic Aldehydes ◽  
Environmentally Benign ◽  
H Nmr ◽  
Sonic Waves ◽  
Ft Ir ◽  
High Yields ◽  
Work Up ◽  
C Nmr

AbstractA simple, straightforward, and ultrasound-promoted method for the preparation of some highly functionalized tetrahydropyridines reported via pseudo five-component reaction of (hetero)aromatic aldehydes, different anilines, and alkyl acetoacetates in the presence of [N-CH2CO2H-3-pic]+HSO4−, as a novel ionic liquid, in green aqueous medium. The IL was synthesized utilizing simple and easily-handled substrates and characterized by FT-IR, 1H NMR, 13C NMR, GC-MASS, FESEM, EDX, and TGA/DTG techniques. The procedure contains some highlighted aspects which are: (a) performing the MCR in the presence of aqua and sonic waves, as two main important and environmentally benign indexes in green and economic chemistry, (b) high yields of products within short reaction times, (c) convenient work-up procedure, (d) preparing the new IL via simple substrates and procedure.

scholarly journals Rapid four-component synthesis of dihydropyrano[2,3-c]pyrazoles using nano-eggshell/Ti(IV) as a highly compatible natural based catalyst

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Arefeh Dehghani Tafti ◽  
Bi Bi Fatemeh Mirjalili ◽  
Abdolhamid Bamoniri ◽  
Naeimeh Salehi
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Reaction Times ◽  
Diffraction Field ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solvent Free Conditions ◽  
High Yields ◽  
Work Up

AbstractNano-eggshell/Ti(IV) as a novel naturally based catalyst was prepared, characterized and applied for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives. The characterization of nano-eggshell/Ti(IV) was performed using Fourier Transform Infrared spectroscopy, X-ray Diffraction, Field Emission Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, and Thermo Gravimetric Analysis. Dihydropyrano[2,3-c]pyrazoles were synthesized in the presence of nano-eggshell/Ti(IV) via a four component reaction of aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate at room temperature under solvent free conditions. The principal affairs of this procedure are mild condition, short reaction times, easy work-up, high yields, reusability of the catalyst and the absence of toxic organic solvents.

scholarly journals Amide-Type Substrates in the Synthesis of N-Protected 1-Aminomethylphosphonium Salts

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 552
Author(s):  
Dominika Kozicka ◽  
Paulina Zieleźny ◽  
Karol Erfurt ◽  
Jakub Adamek
Keyword(s):  
Reaction Times ◽  
The Other ◽  
Hydroxyl Group ◽  
Other Hand ◽  
Step Procedure ◽  
Higher Temperature ◽  
Short Time ◽  
Work Up

Herein we describe the development and optimization of a two-step procedure for the synthesis of N-protected 1-aminomethylphosphonium salts from imides, amides, carbamates, or lactams. Our “step-by-step” methodology involves the transformation of amide-type substrates to the corresponding hydroxymethyl derivatives, followed by the substitution of the hydroxyl group with a phosphonium moiety. The first step of the described synthesis was conducted based on well-known protocols for hydroxymethylation with formaldehyde or paraformaldehyde. In turn, the second (substitution) stage required optimization studies. In general, reactions of amide, carbamate, and lactam derivatives occurred at a temperature of 70 °C in a relatively short time (1 h). On the other hand, N-hydroxymethylimides reacted with triarylphosphonium salts at a much higher temperature (135 °C) and over longer reaction times (as much as 30 h). However, the proposed strategy is very efficient, especially when NaBr is used as a catalyst. Moreover, a simple work-up procedure involving only crystallization afforded good to excellent yields (up to 99%).

Rapid and Green One-Pot Synthesis of Novel 2-(4-Hydroxy-2-oxo-2H-chromen-3-yl)-2-(arylamino)-1H-indene-1,3(2H)-diones

2021 ◽  
Vol 18 ◽  
Author(s):  
Abolfazl Olyaei ◽  
Zahra Ghahremany ◽  
Madieh Sadeghpour
Keyword(s):  
Aromatic Amines ◽  
Low Cost ◽  
Guanidine Hydrochloride ◽  
Reaction Times ◽  
Solvent Free ◽  
One Pot ◽  
Solvent Free Conditions ◽  
The One ◽  
High Yields ◽  
Work Up

: A green and efficient protocol was developed for the one-pot three-component synthesis of novel 2-(4-hydroxy-2-oxo-2H-chromen-3-yl)-2-(arylamino)-1H-indene-1,3(2H)-dione derivatives by the reaction of 4-hydroxycoumarin, ninhydrin and aromatic amines in the presence of guanidine hydrochloride as an organocatalyst under solvent-free conditions. The present approach offers several advantages such as low cost, simple work-up, short reaction times, chromatography-free purification, high yields and greener conditions.

scholarly journals Zn(L-proline)2: An efficient and reusable organocatalyst for the synthesis of polyfunctionally substituted pyrans and 2-amino-4-aryl-8-oxo-4,8-dihydropyrano[3,2-b]pyran derivatives

2019 ◽  
Vol 10 (2) ◽  
pp. 166-170 ◽  
Author(s):  
Fatma Ahmed Abo Elsoud ◽  
Mohamed Abd-Elmonem ◽  
Mohamed Abo Elsebaa ◽  
Kamal Usef Sadek
Keyword(s):  
Kojic Acid ◽  
Aromatic Aldehydes ◽  
Efficient Synthesis ◽  
Atom Economy ◽  
Short Reaction Time ◽  
Biologically Relevant ◽  
Three Component Reaction ◽  
High Yields ◽  
Organometallic Catalyst ◽  
Work Up

Efficient synthesis of non-annulated 2-amino-4H-pyrans and 2-amino-8-oxo-4,8-dihydropyrano[3,2-b]pyran derivatives, which are biologically relevant heterocycles is achieved, utilizing a domino three-component reaction of ethyl acetoacetate or kojic acid with aromatic aldehydes and malononitrile catalyzed by Zn(L-proline)2 as reusable organometallic catalyst. The process exhibits high atom economy, short reaction time, simple work up, high yields and environmentally friendly nature. Excellent yields of the targeted molecules have been obtained.

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