The Beckmann rearrangement of aliphatic ketone oximes, R(CHs)
C
=NOH (R=Et (
1
); n-Pr (2); iso-Pr (
3
); iso-Bu (
4
)), with polyphosphoric acid (PPA), polyphosphate ester (PPE), and ester of phosphoric acid (2 P-
5
R) was carried out and migratory ratios ((a)/(
b
) in eq. (
1
)) were determined, The results are shown in Fig.
1
, 2, and
3
, respectively.
In Fig.
1
and 2, the migratory ratios decrease with reaction time and nearly approach to the ratios of anti-alkyl form/syn-alkylform in benzene(A
1
) or DMSO(A2)except for (
3
) (See Table
1
). From this fact, it has been found that PPA and PPE are inactive for isomerization of the oximes andanti-alkyl oximes rearrange faster than syn-alkyl ones. ln the case of (
3
), migratery ratios are smaller than Ai or A2. As acetonitrile is detected by GLC, it is presumed that fission has been occurred simultaneously with rearrangement in anti-alkyl oxime (eq. (
3
)). In the case of 2 P-
5
R, all modes of the reaction arethe same as in above, except that the rate of fission is tnuch faster than that in PPA and PPE.
The reaction of anti-alkyl ketone oximes having a bulky grouphas been greatly influenced by the use of sterically demanding catalysts such asPPA, PPE, and 2 P-
5
R.
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