Microwave-assisted synthesis of novel spiro isoxazolidine derivatives

Highly Stereoselective Synthesis of New Aziridines via Baldwin Rearrangement and Their Potential Biological Activities

“…These results are not that surprising in light of previous reported examples where strong donating nitrogen substituents appear to favor the rearrangement . A study of the reaction conditions under microwave irradiation was undertaken as this condition is generally faster, cleaner, greener, and very often more selective . The results are summarized in Table .…”

“…The wealthy literature on cycloaddition reactions of nitrones for the synthesis of isoxazolidine, isoxazoline derivatives, and their further applications have been widely illustrated while conversions of isoxazoline derivatives to aziridines are of tremendous interest in this chemistry . As a part of our ongoing research program to develop new methodologies in organic synthesis , herein, we report stereoselective synthesis of new N‐ substituted aziridine derivatives from isoxazolines via Baldwin rearrangement and their biological activities (Scheme ; Table ). The newly reported N‐ substituted aziridine derivatives are obtained as single diastereoisomer when the isoxazoline derivatives are exposed to microwave irradiation for 5–8 min at 90–130°C.…”

Synthesis of Some Novel Class of Bis(isoxazoline) and Bis(aziridine) Derivatives

“…In conventional methodology, high reaction temperature and long reaction time are generally required to obtain good conversions and yields in these cycloaddition reactions but prolonged heating time results in a drastic drop of the yield of cycloadducts because of decomposition. A study of the reaction conditions under microwave irradiation was thus undertaken as this condition is generally faster, cleaner, and greener . The results are summarized in Table .…”

“…Baldwin et al have shown that 1,3‐dipolar cycloaddition reactions of nitrones to alkynes lead to 4‐isoxazolines which rearrange easily under thermal conditions to acylaziridine. As a part of our ongoing research programme to develop new methodologies in organic synthesis , herein, we report synthesis of some new bis(isoxazoline) derivatives (2) from terepthaldehyde in good to excellent yields under microwave irradiation (Scheme , Table ). Furthermore, these bis(isoxazoline) derivatives are found to have vast synthetic potential as they could be converted into synthetically more important new bis(aziridines) (3) .…”

Greening the organic chemistry laboratory: a comparison of microwave-assisted and classical nucleophilic aromatic substitution reactions

“…Furthermore, the present study serves as an excellent introduction to microwave-induced organic reaction enhancement (MORE) which has been shown to be very useful in affecting the pathway of a reaction, the products formed and, especially, reaction times. As such, MORE techniques are appearing more often in the chemical literature (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38). In one study (39), the authors report that the time and yield of their own previously developed synthesis of 2-chloromethylbenzothiazole from ortho-aminothiophenol and polyphosphoric acid, which gives a reasonable yield of 62% after 8 h of reflux at 180°C, improves to a 90% yield with only 10 min of microwave irradiation.…”