It is dcnionstratcd in mass spcctromctry that alkylamincs substitutcd at C2 and containing weak internal cncrgy isorncrizc in thc gas phasc into intermediary ions composcd of ionizcd cyclopropanes co~nplexcd with an ammonia niolcculc. This process is induced by a C3 hydrogen shift on thc nitrogen atom.. Aftcr opening of thc cyclopropanc, thc dissociation of thcsc complcxcs lcads to rn/z 44, 58. and 72 ions having [CH3(CH2),,CH NHZ] structures. Thc nicclianisni of thcir formation is dcmonstratcd by thc MlKE spectra of I3C and deutcriurn labcllcd compounds. Thc cxpcrirncntal rcsults arc in good agrccment with thosc described by Gross e! ell.. who studied thc fragmcntation of thc complcxcs fornicd during thc reaction bctwccn substitutcd ionizcd cyclopropancs and ammonia in thc gas phasc.

No abstract

Radical cations derived from the ethers ROCH,CH,OR (R, R = H, CH, , C,HJ were studied, since Bdistonic oxonium ions are often prepared from ionized ethers of glycol. The first step in the fragmentation is a 1,Stransfer of an a-hydrogen to oxygen of a terminal alkoxy group leading to a Wistonic oxonium ion. This step is thermoneutral and reversible in the ROCH,CH,OH radical cations and exothermic and irreversible in the dialkyl ether radical cations. Depending on R and R', these Sdistonic oxonium ions fragment by three reactions: the loss of an alcohol or a water molecule, the formation of a /Idistonic oxonium ion 'CH2CH20(H)+R and a 1,QH migration between carbon atoms. Competition between these processes is discussed.