Organic Reactions Volume 4 - Sciencemadness Dot Org

36 ORGANIC REACTIONS
hydroxyfuran has not yielded satisfactory results. 277 a-Vinylfuran reacts
readily with maleic anhydride to give an adduct lacking an oxygen
L^ +
QHCO
. /°
CHCO
OC-O
bridge. 276 ' 278 Maleic acid reacts with furan in the same manner as maleic
anhydride, 271 but pyrocinchonic anhydride (dimethylmaleic anhydride)
does not yield the expected adduct. 275
Isobenzofurans, which themselves may be synthesized by means of a
Diels-Alder reaction, 33 react rapidly with maleic anhydride at room
temperature to yield adducts which may be converted easily to naphthalene
derivatives. 38 ' 279-281
Anthranil also reacts with maleic anhydride, but the structure of the
adduct has not been ascertained. 282
In harmony with its greater degree of resonance stabilization, thiophene
is less reactive than furan in the Diels-Alder reaction. 283 Thiophene
does not react with maleic anhydride. 284 2,3,4,5-Di-(I ',8'rnaphthylene)thiophene
(LXXXVIII), however, does react with maleic anhydride. 285
277 Hodgson and Davies, J, Chem. Soc, 1939, 806.
278 Paul, Compt. rend., 208, 1028 (1939).
279 Weiss, Abeles, and Knapp, Monatsh., 61, 162 (1932).
280 Weiss and Mayer, Monatsh., 71, 6 (1937).
281 Bergmann, J. Chem. Soc, 1938, 1147.
282 Schonberg and Mostafa, /. Chem. /Soc, 1943, 654.
283 Schomaker and Pauling, J. Am. Chem. Soc, 61, 1769 (1939).
284 Diels, Ber., 69A, 195 (1936).
286 Clapp, J. Am. Chem. Soc, 61, 2733 (1939).