Peer-Reviewed Journal Details
Mandatory Fields
Butler, RN,McKenna, EC,McMahon, JM,Daly, KM,Cunningham, D,McArdle, P
1997
October
Journal Of The Chemical Society-Perkin Transactions 1
Ring expansions of N-methyl-1,2,5-oxadiazolium and 1,2,3-triazolium perchlorate salts with bases to six-membered azines: direct detection of an addition intermediate in an addition-elimination mechanism and a degradation of 1,2,5-oxadiazolium salts to alpha-cyano nitrones
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Optional Fields
AZOLIUM 1,3-DIPOLES N-OXIDES REACTIVITY CARBENE SYSTEM ROUTES
2919
2923
Reactions of 2-methyl-1,2,5-oxodiazolium perchlorate salts and 1-methyl-2-aryl-1,2,3-triazolium perchlorate salts with the bases KCN, NaOEt, KOBut, LiNPr2i, give ring expansions to substituted 1,2,5-oxadiazines and 1,2,4-triazines. With cyanide as base the reactions follow an addition-elimination pathway and in two cases the addition intermediate has been isolated or directly detected by low-temperature NMR spectroscopy. The oxadiazolium system with cyanide also gives a useful new route to alpha-cyano nitrones via a ring degradation which competes with ring expansion. The reactions with KOBut and LiNPr2i do not involve an addition of the base to the azolium salt. Reactions have been monitored by C-13 NMR spectroscopy by using (CN-)-C-13. An X-ray crystal structure is reported for (E)-N-(alpha-cyanobenzylidene)methylamine N-oxide.
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