Organic Reactions Volume 4 - Sciencemadness Dot Org

70 ORGANIC REACTIONS
Derivatives of hydrophenanthrene and phenanthrene have been
prepared from compounds in which rings A and C are preformed and
by generation of ring C. A 68% yield of 9-phenyldodecahydrophenanthrene-10-carboxylic
acid was obtained by heating equimolar amounts
of bicyclohexenyl and cinnamic acid in a sealed system. 22 This product
is often accompanied by traces (4%) of a high-melting isomer, whereas
in an open system the presence of the second product has not been
observed. 21 Dehydrogenation of the normal bicyclohexenyl-cinnamic
acid adduct with sulfur afforded 9-phenyl-10-phenanthroic acid, whil^
with selenium a good yield of 9-phenylphenanthrene resulted.
Generation of ring B of phenanthrene by lengthening the side chain
of IX, followed by cyclization, failed at the first stage, for with hydrogen
cyanide the benzoin, XXIX, was obtained instead of the expected cyanohydrin.
2
^^cocHoir
XXIX
The second type of phenanthrene synthesis has been applied to the
synthesis of possible degradation products of morphine. Butadiene,
2-ethoxybutadiene, 22a and 2,3-dimethylbutadiene have been added to
3,4-dihydro-l-naphthoic acid (ester) 23,24 as well as to the 7-methoxy 23 » 24
and 5-bromo-7,8-dimethoxy derivatives. 23 The yields of adducts were
quite satisfactory with 2,3-dimethylbutadiene, but from butadiene and
5~bromo-7,8-dimethoxy-3,4-dihydro-l-naphthoic acid the yield of the
acid adduct (XXX) was 18%, and of the methyl ester, 8%. Similar
HO2C
R«H, Br
R-H, OCH3
XXX
22 Weizmann, Bergmann, and Berlin, J. Am. Chem. Soc, 60, 1331 (1938).
22a Holmes and Mann, J. Am. Chem. Soc, 69, 2000 (1947),
23 Fieser and Holmes, /. Am. Chem. Soc, 60, 2548 (1938).
24 Fieser and Holmes, J, Am. Chem* Soc, 58, 2319 (1936).