4,400-Diamino-p-terphenyl
1345
of 1-bromo-4-nitrobenzene 2 (0.092 mol, 2 equiv), 400 mL of THF, and 92 mL
of 2 M K2CO3 (0.184 mol, 4 equiv). A reflux condenser and N2 bubbler were
attached, and the mixture was heated gently to dissolve all the solids. Tetra-
kis(triphenylphosphine)palladium(0) (600 mg) was added in one portion,
and the mixture was refluxed for 18 h. The product precipitated from the
reaction mixture as the reaction proceeded. After this time, the mixture was
cooled to rt, and 200 mL of H2O was added. The solids were collected on a
medium-porosity glass frit and washed with 200 mL of H2O. The solids
were transferred to a 500 mL beaker and recrystallized from 250 mL of
DMF. The bright yellow powder was collected on a medium-porosity
glass frit, washed with EtOH, and air dried on the frit (11.2 g, 76%). Mp
270–2728C (lit.[2] 274–2758C). dH (DMSO-d6): 8.35 (d, J ¼ 8.8 Hz, 4H),
8.07 (d, J ¼ 9.0 Hz, 4H), 7.99 (s, 4H); dC (DMSO-d6 at 1258C): 146.70,
145.18, 137.86, 127.38, 127.26, 123.37. Anal. calcd. for C18H12N2O4: C,
67.5; H, 3.78; N, 8.75. Found: C, 67.51; H, 3.62; N, 8.64.
4,400-Diamino-p-terphenyl (4)
A mixture of 26.8 g of 3, 1-L of THF (containing 250 ppm BHT), and 2 g of
5% Pd on carbon catalyst were shaken on a Parrw hydrogenator for 18 h
(40 psig). After 1 h, the reaction mixture appeared orange and opaque. After
18 h, the mixture was colorless. To the reaction mixture were added 500 mL
of hexanes, and then the mixture was filtered through diatomaceous earth
on a coarse glass frit. The addition of hexanes ensured complete removal of
the catalyst by a single filtration; otherwise a small amount of catalyst was
inevitably entrained. The colorless filtrate was rotary evaporated, leaving a
white solid. The material was placed under vacuum to remove residual
solvent (rt, 1 Torr) and was pure by NMR. An analytical sample was made
by recrystallization from MeCN, providing the title compound as small
colorless plates. Mp 240–2418C with decomposition (lit.[4] 248–2538C and
lit.[5] 2408C). The product can also be recrystallized from 1,4-dioxane or
toluene. dH (DMSO-d6): 7.56 (s, 4H), 7.41 (d, J ¼ 8.3 Hz, 4H), 6.69
(d, J ¼ 8.3 Hz, 4H); dC (DMSO-d6): 148.19, 137.96, 127.24, 126.89,
125.63, 114.36. Anal. calcd. for C18H14N2: C, 83.04; H, 6.19; N, 10.76.
Found: C, 82.75; H, 6.21; N, 10.60.
ACKNOWLEDGMENT
Financial support from the Office of Naval Research is gratefully acknowl-
edged. The author thanks Geoffrey A. Lindsay, Naval Air Warfare Center
Weapons Division for advice and encouragement throughout the course of
this work. Thanks to Andrew P Chafin, Naval Air Warfare Center Weapons
Division for comments and suggestions regarding the manuscript.