Organic Reactions Volume 4 - Sciencemadness Dot Org

42 ORGANIC REACTIONS
again heated on a water bath for about ten minutes to complete the
reaction. The addition product begins to separate from the warm mixture
as a mass of colorless crystals, and, upon cooling, the mixture sets
to a thick paste. The 3~phenyl~aVl,2,3,64etrahydrophthalic anhydride
is crystallized from benzene-ligroin; colorless needles, m.p. 120°.
Reaction of Maleic Anhydride with l,2-Diphenyl-l,3-*pentadiene. 821
l?2-DiphenyM,3~pentadiene (5 g.) and maleic anhydride (3 g.) are
heated for three hours in boiling nitrobenzene (15 ml.). The 3,4diphenyl-6-methylphthalic
anhydride begins to separate during the
heating. After standing for forty-eight hours the product is collected
and recrystallized from petroleum ether (b.p. 130°); m.p. 161°.
Reaction of Citraconic Anhydride with Cyclopentadiene. 5 Citraconic
anhydride (5 g.) dissolved in benzene (5 ml) is treated with cyclopentadiene
(3 g.)„ Vigorous evolution of heat takes place after a short time.
After standing for several hours the solvent is evaporated at room temperature.
The product is obtained as a faintly colored, viscous oil which
changes to a compact mass of colorless crystals upon standing in a
desiccator for two or three days. Two crystallizations from petroleum
ether yield pure l-methyl-3,6-endomethylene-l,2,3,6-tetrahydrophthalic
anhydride, m.p. 138°.
Reaction of Maleic Anhydride with 9-Methylanthracene. 128 9-Methyl-
OjlO-dihydroanthracene-OjlO-e^o-a^-succinic anhydride crystallizes in
95% yield as colorless needles from a solution of 0.5 g. of 9-methylanthracene
and 0.25 g. of maleic anhydride in 10 ml. of benzene which has been
refluxed for two hours; m.p. 264-266°.
Reaction of Maleic Anhydride with 1,2-Benzanthracene. 123 9,10-Dihydro-l^-benzanthracene^ylO-endo-a^-succinic
anhydride is isolated
by heating a mixture of 0.4 g. of 1,2-benzanthracene and 5 g. of maleic
anhydride in 8 ml. of boiling benzene for three hours, evaporating the
solvent, and distilling the excess maleic anhydride from the mixture
at 80° at 0.4 mm. The residue is washed with benzene; yield, 0.26 g.
(46%).
Reaction of Maleic Anhydride with Isoeugenol Methyl Ether, 101 A
mixture of 24 g. of isoeugenol methyl ether, 18 g. of maleic anhydride,
and 50 ml. of xylene is refluxed for five hours and then allowed to stand
for two days; 45 ml, of xylene is then distilled. The residual orangered,
glassy mass is boiled with 200 ml of ethanol, whereupon 30 g. of
a solid separates (m.p. 101-103°). This is dissolved in chloroform, and
a little petroleum ether is added to precipitate a small quantity of
polymeric material. The adduct is recovered from the filtrate and
recrystallized from acetic anhydride or from a relatively large volume
of petroleum ether (b.p. 80-100°). 6,7-Dimethoxy-3-methyH,2,3,4«