Coupling of diazopurines, a curious steric effect in a free radical reaction

McKenzie, Thomas C.; Epstein, Joseph

doi:10.1021/jo00146a013

Cited by 38 publications

(28 citation statements)

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“…The organozinc reagent 1 can serve as a good building block for the attachment of diand tetrahydrofuran to other types of compounds through a C-C bond. [20] 2b, [21] 2c, [22] and 2d [23] were prepared according to literature procedures. Mass spectra were measured using FAB (ionization by Xe, accelerating voltage 8 kV, glycerol + thioglycerol matrix) or EI (electron energy 70 eV) techniques with a ZAB-EQ (VG Analytical) spectrometer.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of 6‐(4,5‐Dihydrofuran‐2‐yl)‐ and 6‐(Tetrahydrofuran‐2‐yl)purine Bases and Nucleosides

Bambuch¹,

Pohl²,

Hocek³

2008

Eur J Org Chem

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A novel approach to the synthesis of purine derivatives (bases and nucleosides) bearing 4,5-dihydrofuran-2-yl and tetrahydrofuran-2-yl substituents at the 6-position as partly and fully saturated analogues of biologically active 6-hetarylpurine nucleosides is reported. Palladium-catalyzed crosscoupling reactions of 6-iodopurines with new (4,5-dihydrofuran-2-yl)zinc chloride (1) gave 6-(4,5-dihydrofuran-2-yl)-

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Section: Resultsmentioning

confidence: 99%

Synthesis of 6‐(4,5‐Dihydrofuran‐2‐yl)‐ and 6‐(Tetrahydrofuran‐2‐yl)purine Bases and Nucleosides

Bambuch¹,

Pohl²,

Hocek³

2008

Eur J Org Chem

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“…The solvents were dried and degassed by standard procedures; silica gel (ICN SiliTech, 32-63) was used for column chromatography. 9-Benzyl-6-iodopurine [26] (1), 7-benzyl-6-iodopurine…”

Section: Discussionmentioning

confidence: 99%

Heck Reactions of 6‐ and 2‐Halopurines

Tobrman

Dvořák

2008

Eur J Org Chem

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Under the conditions of the Heck reaction, 9-benzyl-6-iodopurine affords mainly the corresponding 6,6Ј-dimer, the Heck product being formed only in low yield (Յ12 %). With 7-benzyl-6-iodopurine the dimerization is suppressed and the Heck product is obtained in 32-91 % yield. 9-Substituted 6-chloro-2-iodopurines react smoothly, giving 2-alkenyl-6- IntroductionAmong a vast number of biologically active purine derivatives, alkenylpurines play an important role.[1] 6-Alkenylpurines, for example, are associated with antimycobacterial, [2] cytotoxic [3] and cytokinin [4] activity and with inhibition of 15-lipoxygenase.[5] Some 6-alkenylpurines have been designed as covalent analogues of DNA base pairs [6] or novel cross-linking agents, [7] and have also been used for the synthesis of fluorescent nucleoside analogues.[8] Moreover, 2-alkenyladenosine derivatives have been reported to function as inhibitors of adenosine receptors. [9] Several methodologies have been used for the preparation of alkenylpurines. 6-Styrylpurine was first prepared by condensation of 6-methylpurine with benzaldehyde in the presence of HCl.[10] Another, more general, synthetic approach to 6-alkenylpurines, is based on Wittig reactions between 9-protected (purin-6-yl)methylene-triphenyl-λ 5 -phosphanes (Wittig reagents) and aldehydes or ketones.[11]Cyclic 6-alkenyloxypurines have been prepared by intramolecular cyclization of 6-(hydroxyalkyn-1-yl)purines, [12] while 6-enaminopurines are accessible by addition of amines to 6-alkynylpurines.[13] Partial hydrogenation of 2-alkynyl- [14] and 8-alkynylpurines [15] to give the corresponding alkenes has also been reported. Hydrogenation of 6-alkynylpurines to 6-alkenylpurines was reported to proceed satisfactorily only with 9-unprotected bases, with overhydrogenation taking place otherwise.[4a] However, the most versatile methodology for the preparation of alkenylpurines -nowadays used almost without exception -is based on transitionmetal-catalyzed cross-coupling reactions.[16] Alkenylpurines [a]

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“…Unless stated otherwise, all reactions were performed in flame‐dried Schlenk flasks under argon. 9‐Benzyl‐6‐iodopurine ( 6a ) and 9‐( O , O , O ‐triacetyl‐β‐ d ‐ribofuranosyl)‐6‐iodopurine ( 6b ) were prepared according to literature procedures. Other compounds were purchased.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Potentially Biologically Active 6‐(1,3‐Butadiynyl)purines

Krovacek

Dvořák

2014

Journal of Heterocyclic Chem

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in Wiley Online Library (wileyonlinelibrary.com).1,3-Alkadiynyl(trimethyl)silanes were prepared by the Negishi or Sonogashira reactions of bromoethynyl (trimethyl)silane with several terminal alkynes in 34-75% yield. However, the direct Hiyama coupling of these compounds with 6-iodopurine derivatives has not been successful. Therefore, a modified Sonogashira reaction using TBAF or CsF for in situ removal of the trimethylsilyl group has been utilized. This methodology afforded the desired 6-(1,3-butadiynyl)purines in 47-87% yield.

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Coupling of diazopurines, a curious steric effect in a free radical reaction

Cited by 38 publications

References 0 publications

Synthesis of 6‐(4,5‐Dihydrofuran‐2‐yl)‐ and 6‐(Tetrahydrofuran‐2‐yl)purine Bases and Nucleosides

Synthesis of 6‐(4,5‐Dihydrofuran‐2‐yl)‐ and 6‐(Tetrahydrofuran‐2‐yl)purine Bases and Nucleosides

Heck Reactions of 6‐ and 2‐Halopurines

Synthesis of Potentially Biologically Active 6‐(1,3‐Butadiynyl)purines

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