Novel solvent‐free labelling procedure with carbon‐14 diethyl malonate

Hernandez, Louis; Casanova, Esther; Loupy, André; Petit, Alain

doi:10.1002/jlcr.653

Cited by 7 publications

(2 citation statements)

References 8 publications

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“…According to this strategy the malonate is first allylated then subjected to the desired alkylation. Moreover, microwave treatment of the diester product with LiF or LiCl (Krapcho procedure) under solvent-free conditions provides the corresponding mono-ester by selective decarbalkoxylation 207 . For the example shown an overall yield of 75% was achieved 206 Figure 6.100 Synthesis of isotopically labeled monoalkylated malonates following a protection/deprotection approach These alkylation procedures can benefit greatly from the use of microwave activation, which can reduce reaction times by a factor of 60.…”

Section: A-alkylation Of [ 14 C]malonatesmentioning

confidence: 99%

Preparation of Carbon‐14‐Labeled Compounds via Multi‐Carbon Building Blocks of the [ ¹⁴ C]Carbon Dioxide Tree

Voges¹,

Heys

Moenius

2009

Preparation of Compounds Labeled With Tritium and Carbon‐14

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Section: A-alkylation Of [ 14 C]malonatesmentioning

confidence: 99%

Preparation of Carbon‐14‐Labeled Compounds via Multi‐Carbon Building Blocks of the [ ¹⁴ C]Carbon Dioxide Tree

Voges¹,

Heys

Moenius

2009

Preparation of Compounds Labeled With Tritium and Carbon‐14

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“…The method is especially useful in the one-pot 14C fatty esters labelling [4] if it is combined with solvent-free microwave-assisted dealcoxycarbonylation (Krapcho reaction), instead of the time-consuming decarboxylation.…”

Section: Introductionmentioning

confidence: 99%

Labelling with diethyl-[2-14C]-malonate in solvent-free conditions

Hernandez¹,

Casanova²,

Loupy

et al. 2003

Czech J Phys

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The Krapcho Dealkoxycarbonylation Reaction of Esters with α‐Electron‐Withdrawing Substituents

Krapcho

Ciganek

2013

Organic Reactions

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The Krapcho reaction involves esters with α‐electron‐withdrawing substituents such as malonates, β‐keto esters, and α‐cyano esters, which undergo dealkoxycarbonylation on being heated in polar aprotic solvents (such as DMSO, DMF, or HMPT) in the presence of water, or in polar aprotic solvents with water in the presence of added salts (such as NaCN, NaCl, LiCl, LiI, or MgCl 2 ). This procedure avoids the use of strongly aqueous acidic and alkaline conditions and tolerates many functional and protecting groups. The chapter presents the mechanistic aspects of this procedure, which include reaction parameters such as solvents, salts, other additives, and the use of microwave irradiation. The diastereoselectivity of protonation of the enolate intermediate leading to the dealkoxycarbonylated products is discussed. Trapping of the intermediate enolate by electrophiles other than a proton is illustrated. Potential side reactions and same‐pot subsequent reactions of substrates are discussed along with functional‐group compatibility for halogens and nitrogen, oxygen, sulfur, selenium, and carbon functional groups. Several examples of applications of this methodology for the synthesis of natural products along with experimental conditions and procedures are presented. Closely related methods are discussed in the Comparison with Other Methods section. The tables, which consist of 371 pages, are grouped according to substrate structure. Selective entries for other methods (excluding classical aqueous acidic or basic methods) are included in the tabular survey for comparative purposes.

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Novel solvent‐free labelling procedure with carbon‐14 diethyl malonate

Abstract: SummaryA rapid and novel one-pot radiochemical synthesis of 14 C-labelled esters has been developed using a combination of solvent-free conditions and microwave irradiation. The method offers several advantages over the customary classical procedure.

Cited by 7 publications

References 8 publications

Preparation of Carbon‐14‐Labeled Compounds via Multi‐Carbon Building Blocks of the [ ¹⁴ C]Carbon Dioxide Tree

Preparation of Carbon‐14‐Labeled Compounds via Multi‐Carbon Building Blocks of the [ ¹⁴ C]Carbon Dioxide Tree

Labelling with diethyl-[2-14C]-malonate in solvent-free conditions

The Krapcho Dealkoxycarbonylation Reaction of Esters with α‐Electron‐Withdrawing Substituents

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Novel solvent‐free labelling procedure with carbon‐14 diethyl malonate

Abstract: SummaryA rapid and novel one-pot radiochemical synthesis of 14 C-labelled esters has been developed using a combination of solvent-free conditions and microwave irradiation. The method offers several advantages over the customary classical procedure.

Cited by 7 publications

References 8 publications

Preparation of Carbon‐14‐Labeled Compounds via Multi‐Carbon Building Blocks of the [ 14 C]Carbon Dioxide Tree

Preparation of Carbon‐14‐Labeled Compounds via Multi‐Carbon Building Blocks of the [ 14 C]Carbon Dioxide Tree

Labelling with diethyl-[2-14C]-malonate in solvent-free conditions

The Krapcho Dealkoxycarbonylation Reaction of Esters with α‐Electron‐Withdrawing Substituents

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Product

Resources

About

Preparation of Carbon‐14‐Labeled Compounds via Multi‐Carbon Building Blocks of the [ ¹⁴ C]Carbon Dioxide Tree

Preparation of Carbon‐14‐Labeled Compounds via Multi‐Carbon Building Blocks of the [ ¹⁴ C]Carbon Dioxide Tree