Pyrrolidine and 1,3-oxazolidine formation from azomethine ylides influenced by change from classical conditions to microwave irradiation
| Autoři | |
|---|---|
| Rok publikování | 2002 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | ARKIVOC |
| Fakulta / Pracoviště MU | |
| Citace | |
| www | http://www.arkat-usa.org/ark/journal/Volume2/Part3/Tisler/MT-316B/316B.htm |
| Obor | Organická chemie |
| Klíčová slova | 1;3-Dipolar cycloaddition; azomethine ylides; pyrrolidines; 1;3-oxazolidines; microwave initiation; mineral support; solvent free conditions |
| Popis | The reactions of ethyl N-alkylaminoacetates 1 in the presence of formaldehyde and dipolarophiles fumaronitrile and dimethylfumarate 3were investigated. They were followed and the results compared of reactions under classical heating and heating by MW either in solvent or without solvent or with solid supports. It has been found out that application of specific reaction conditions for the preparation of desired trisubstituted pyrrolidines 4a-4c and 5a-5c is dependent on the nature of the dipolarophile used. In the case of fumaronitrile the direct solventless reaction under microwave irradiation seems to be the most convenient method; in thecase of dimethyl fumarate mineral support (predominantly basic activated Al2O3) must be employed. In the absence of olefinic dipolarophile double bond C=O in a formaldehyde molecule serves as dipolarophile9 to form 1,3-oxazolidines 6a-6c. These are also by-products when toluene is used as a solvent.1 Yet in the case of addition of basic Al2O3 we do not observe oxazolidine formation and GC-MS analysis shows just a complex set of peaks. |
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