Organic Reactions Volume 4 - Sciencemadness Dot Org

FOOTNOTES TO TABLE IX
1
The melting point is corrected.
2
The position of the double bonds is not definitely established.
3
The same tetraphenylbenzene was obtained from the tetraphenylcyclopentadienone-maleic anhydride adduct.
4
The structure of the adduct has not been established.
5
The reaction is exothermic.
6
The product used was about 30% eyclohexadiene.
7
This dihydro ester can be catalytically reduced over colloidal palladium to give, after saponification, the A^tetrahydro acid. This is identical with that ob- _
tained by Diels and Alder 12 from cyclohexadiene and dibromomaleic anhydride. ^
8
This addition product was not isolated but was immediately reduced to the A ^tetrahydro adduct. Q
9
The structure of this diene is not definitely known. £>
10
At the temperature of this reaction the primary addition product is unstable and loses a molecule of ethylene. ^
11
The acid melts at 232°. J^
12
The reaction product was dehydrogenated to 3,6-diphenylphthalie acid and this in turn converted to terphenyl. O
13
The reaction mixture was heated for an additional five minutes at 200°. \-*
14
A molecule of isopropylethylene is lost during the reaction. ^
15
For identification the diester was saponified to 4-methyiphthalie acid. £>.
16
The reagent used in this reaction was that obtained directly from the dehydration of a-terpineol. Q
17
During the dehydration of a-terpineol to a-terpinene an isomeric product containing a conjugated diene system is formed, for it also reacts with ethyl acetj- H
Ienediearboxylate. Unlike the a-terpinene adduct, this adduct does not lose ethylene during the distillation. Q
18
Ethylene is evolved during the reaction. J^
19
This diester cannot be saponified. U2
20 The reaction gave an ill-defined oily condensation product.
21 The anhydride from this diester is identical with that obtained from anthracene and dibromomaleic anhydride followed by the elimination of the bromine.
22 Methyl A l > 4 -dihydrophthalate was reduced to the A ^tetrahydro ester. Bromine removed four hydrogen atoms from the A ^--tetrahydro acid to give phthalic
acid.
23 There is no thermal cleavage of the propano bridge.
24 The reaction mixture was heated until it was a deep brown.
25 The endo-caxhonyl group is lost as a molecule of carbon monoxide.
26 The acid melts at 206-207°.
27 ThC acid melts at 152-153°.