Organic Reactions Volume 4 - Sciencemadness Dot Org

38 ORGANIO REACTIONS
molecule of maleic anhydride adds to yield XCIV. Substituted coumalins
react in a similar manner.
D
anhydride
PO
anhydride
160°
XOIII XOIV"
Although many nitrogen heterocycles react readily with maleic anhydride,
they fail to yield normal adducts.* In the pyrrole series the
active a-position is attacked to give a-pyrrylsuccinic anhydrides. 6,291 - 292
CH-
Il
CH
-
\ /
N
CH CHCO
11+11 >0
CH CHCO
CH-CH
CH C-CH-CH2
\ / I I
N CO CO
CH3 CH3 O
Furan and a-methylfuran undergo similar substitution reactions with
acrolein, 293 crotonaldehyde, methyl vinyl ketone, and vinyl phenyl ketone
294 under the catalytic influence of sulfur dioxide or other sulfurcontaining
compounds.
If reaction of a pyrrole with maleic acid is effected in hot aqueous
solution, the pyrrylsuccinic acids initially produced are decarboxylated
and hydrolyzed to some extent, depending upon the pyrrole derivative
employed.
CH
IH
N
H
-CH CHCO2H
CH-
CH CHCO2H
HO2CCH2CHi
O2H N
H
-CH
h
ICHCH2CO2H
CO2H
CH CH
HO2CCH2CH2- CH2CH2CO2H HOH
CH2—CH2
> HO2CCH2CH2C CCH2CH2CO2H
H
* Hopff and Rautenstrauch> U. S. pat. 2,262,002 [C. A., 36,1046 (1042)], have reported,
without citing evidence, that N-isobutylmaleimide reacts with pyrrole to yield a tetrahy
dro-endo-N-phthalimide.
291
Diels, Alder, and Winter, Ann., 486, 211 (19Sl).
292
Diels, Alder, Winckler, and Petersen, Ann., 498, 1 (1932).
293
Sherlin, Berlin, Serebrennikova, and Rabinovich, /. Gen. Chen. U.8.S.R., 8, 7 (1938)
[C. A., 32, 5397 (1938)].
294
Alder and Schmidt, Ber., 76, 183 (1943),