Beta cleavage

In a few cases extensive cleavage of the substrate molecule occurs The case documented [JS] involves beta cleavage of tetramethylorthocarbonate and tri-methylorthoacetate The mechanism of this reaction involves the formation of a radical which can form a more stable radical by eliminating a stable molecule by beta cleavage Interestingly tetramethylorthocarbonate seems to suffer less cleav age by the LTG method [9] Examples of beta cleavage during direct fluorination are shown in equahons 6-9, where AF is aerosol direct fluorination procedure... 

Rice has shown that the cracking of hydrocarbons at high temperatures gives free radicals.48 Only the methyl and ethyl radicals survive long enough to react with mercury to give dialkylmercury. Presumably the others decomposes by a beta cleavage process. 

The following are topics that may be especially valuable to the student and which might be read initially in Chapter 12, lysozyme (Section B,5), chymo-trypsin (Section C,l), kinases (Section D,9), multiple displacement, reactions (Section G) in Chapter 13, imines (Section A,2), addition to C=C bonds (Section A, 4,5), beta cleavage and condensation (Section C) in Chapter 14, thiamin diphosphate (Section D), pyridoxal phosphate (Section E) in Chapter 15, NAD (Section A). 

Beta cleavage yielding >C=N< base peak for all 1 ° amines at m/e = 30 (CH NHj) moderate M-1 peak for aromatic... 

Ketones and aromatic aldehydes show strong molecular ion peaks, while aliphatic aldehydes give a weak but measurable molecular ion peak. Both ketones and aldehydes fragment by alpha cleavage. Aldehydes also fragment by beta cleavage, at the bond shown ... 

Certain polymers degrade in the presence of decomposing peroxides. This Is due to beta cleavage associated with special structural features of the polymer. Polymers that undergo beta cleavage are polypropylene, butyl, polyisobutylene, and polyepi-chlorohydrin. 

Amines Hardly detectable in case of acyclic aliphatic amines high intensity for aromatic and cyclic amines Beta cleavage yielding >C=Nv base peak for all 1° amines at m/e = 30 (CH2=N+H j moderate M-1 peak for aromatic amines loss of 27 (HCN) in aromatic amines fragmentation at alpha carbons in cyclic amines... 

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