Organic Reactions Volume 4 - Sciencemadness Dot Org

76 ORGANIC REACTIONS
diphenylisobenzofuran and its 5,6-dimethyl derivative has been reported.
The reaction of nitroethylene with cyclopentadiene at 110° appears
to follow the Alder rule. The single product isolated is probably the
endo form (XLII, R = H), for this nitro adduct and the cyclopentadieneacrylic
acid adduct both yield the same enrfo-norbornylamine. 11 ' 36 ' 37 « 38
+
CHR
CHNO2 "NO3
R-H, CH8, C3H7
Substituted 2,3-dimethyl-l ,4,11,12-tetrahydrophenanthridines
(XLIV) have been prepared in 70-80% yield from the N-acyl derivatives
of XLIII. The Hofmann degradation of the amide from the acid adduct
H3C1
CH3
NH2
RR' = 2-OCH3, CH202<
XLIII
H3C
XLII
CH
R' « H, C6H6
XLIV
of 3,4-dimethoxycinnamic acid (and ethyl ester) and 2,3-dimethylbutadiene
failed. However, the amines (XLIII) for this synthesis were
obtained by electrolytic reduction (lead cathode) of the nitro adducts
XLV from 2,3-dimethylbutadiene and 3,4-dimethoxy and 3,4-methylenedioxy
derivatives of /5-nitrostyrene.
R'
RR
R
F
t._.
-\_/~
NO2
2-OCH3,
XLV
CH3
VH3
CH2OiK
36 Alder, Rickert, and Windemuth, Ber., 71, 2451 (1938).
37 Kenyon and Young, J. Chem. Soc, 1941, 263.
38 Jones and WaIUs, /. Am. Chem. Soc, 48, 169 (1926).