Solvent free protection of carbonyl group under microwave irradiation

Perio, Bertrand; Dozias, Marie‐Joelle; Jacquault, P.; Hamelin, J.

doi:10.1016/s0040-4039(97)10149-6

Cited by 70 publications

(25 citation statements)

References 29 publications

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“…was irradiated in a Prolabo (Synthewave ® ) oven for 30 minutes (the monitored temperature 120 ºC with a maximum emitted power of 120 W), a low conversion (20 %) was observed with acetophenone, whereas, benzophenone did not react at all. [11] Ketalization of some acetophenones with ethylene glycol has been described in a Teflon cylinder under microwave irradiation in the presence of water in 30-80 % yield, however, the results are not supported by sufficient evidence to be considered reliable. [12] In this paper we describe a simple and convenient synthesis of acetophenone and benzophenone ethylene ketals by performing the reaction of the starting materials with ethylene glycol in toluene in the presence of PTSA under microwave irradiation and with simultaneous removal of the so formed water.…”

Section: Methodsmentioning

confidence: 99%

Microwave assisted synthesis of benzophenone and acetophenone ethylene ketals

Lukács¹,

Porcs-Makkay²,

Komáromi³

et al. 2007

Arkivoc

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Dedicated to Professor Csaba Szántay on the occasion of his 80th birthdayAbstract A simple and convenient synthesis of acetophenone and benzophenone ethylene ketals was elaborated by performing the reaction of ethylene glycol in toluene in the presence of PTSA, under microwave irradiation with simultaneous removal of the water so formed. Under these conditions 100 % conversion and high yields were obtained within short reaction times.

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Section: Methodsmentioning

confidence: 99%

Microwave assisted synthesis of benzophenone and acetophenone ethylene ketals

Lukács¹,

Porcs-Makkay²,

Komáromi³

et al. 2007

Arkivoc

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“…Unfortunately, the comparison is not reliable because the temperature was not measured in the domestic oven. It has been shown [61] that yields are higher under the action of irradiation. This reaction is readily achieved under microwave irradiation in high yields in 4 to 30 min (Scheme 8.43).…”

Section: Dioxolane Synthesismentioning

confidence: 99%

“…A mixture of an aldehyde or a ketone with ethylene glycol (EG) and p-toluenesulfonic acid (pTSA) leads to the corresponding dioxolane, after irradiation [61] (Scheme 8.42). Unfortunately, the comparison is not reliable because the temperature was not measured in the domestic oven.…”

Section: Dioxolane Synthesismentioning

confidence: 99%

Microwaves in Heterocyclic Chemistry

Hamelin

Bazureau

Texier‐Boullet

2002

Microwaves in Organic Synthesis

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The palladium-catalyzed Heck [1], Suzuki [2] and Stille [3] reactions are robust and general methods for C±C bond-formation and have therefore emerged as important reactions in the synthesis of natural heterocyclic compounds.Hallberg and coworkers [4 a] have used a single-mode microwave oven [4 b] at 50 W to improve radical-mediated reduction and cyclization of the heterohalide 1 with HSn(CH 2 CH 2 C 10 F 21 ) 3 2 in benzotrifluoride (BTF). The authors claim the preparation of 3 in high yield (93 %) after 5 min, as illustrated in Scheme 8.1.The efficiency of fluorous Stille coupling reactions [5 a] is enhanced by use of microwave irradiation (Scheme 8.2). The reaction proceeds in 79 % yield after 2 min with DMF as the microwave-active solvent.

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“…The yields ob- tained with the microwave method are better than those obtained using conventional heating in an oil bath [32]. This acid-catalyzed reaction proceeds in the presence of p-toluenesulfonic acid (p-TsOH) or KSF clay under solvent-free conditions (Scheme 6.2).…”

Section: Formation Of Acetals and Dioxolanesmentioning

confidence: 99%