Synthesis of Pyrrolo[3,2-b]pyrrole-2,5-diones
J . Org. Chem., Vol. 65, No. 3, 2000 733
1,4-Bis(4-t olyl)-3,6-b is(d ip h en ylim in o)p yr r olo[3,2-b]-
p yr r ol-2,5-d ion e (4k ). IR (Nujol, cm-1): ν˜ ) 1717 (s, νCO),
1675 (s, νCdC). MS [CI (H2O), m/z (%)]: 675 (M+ + 1, 100). Anal.
Calcd for C46H34N4O2 (674.80): C, 81.88; H, 5.08; N, 8.30.
Found: C, 81.24; H, 5.49; N, 8.21.
toward the synthesis of unsymmetrical, push-pull sub-
stituted pyrrolo[3,2-b]pyrrole-2,5-diones for the develop-
ment of new pigment dyes which exhibit absorptions in
the NIR range.14,15
1,4-Bis(4-tolyl)-3,6-bisp h en ylp yr r olo[3,2-b]p yr r ol-2,5-
d ion e (4l). IR (Nujol, cm-1): ν˜ ) 1726 (s, νCO), 1645 (s, νCdC).
MS [CI (H2O), m/z (%)]: 469 (M+ + 1, 100), 234 (14). Anal.
Calcd for C32H24N2O2 (468.55): C, 82.03; H, 5.16; N, 5.98.
Found: C, 82.14; H, 5.12; N, 5.71.
1,4-Bis(4-t olyl)-3,6-b is(4-br om op h en yl)p yr r olo[3,2-b]-
p yr r ol-2,5-d ion e (4m ). IR (Nujol, cm-1): ν˜ ) 1733 (s, VCO),
1651 (s, νCdC). MS [CI (H2O), m/z (%)]: 627 (M+ + 1, 100), 149
(21). Anal. Calcd for C32H22N2O2Br2 (626.35): C, 61.36; H, 3.54;
N, 4.47. Found: C, 60.46; H, 3.49; N, 4.52.
1,4-Bis(4-tolyl)-3,6-bis(4-tolyl)p yr r olo[3,2-b]p yr r ol-2,5-
d ion e (4n ). IR (Nujol, cm-1): ν˜ ) 1728 (s, νCO), 1644 (s, νCdC).
MS [CI (H2O), m/z (%)]: 497 (M+ + 1, 46), 108 (14), 74 (100).
Anal. Calcd for C34H28N2O2 (496.61): C, 82.23; H, 5.68; N, 5.64.
Found: C, 81.33; H, 5.69; N, 5.82.
1,4-Bis(4-tolyl)-3,6-bis(4-m eth oxyp h en yl)p yr r olo[3,2-b]-
p yr r ol-2,5-d ion e (4o). IR (Nujol, cm-1): ν˜ ) 1729 (s, νCO),
1653 (s, νCdC). MS [CI (H2O), m/z (%)]: 529 (M+ + 1, 100), 119
(35). Anal. Calcd for C34H28N2O4 (528.61): C, 77.25; H, 5.34;
N, 5.30. Found: C, 76.84; H, 5.29; N, 5.55.
Exp er im en ta l Section
Gen er a l P r oced u r e for th e P r ep a r a tion of P yr r olo[3,2-
b]p yr r ol-2,5-d ion es (4). To a THF solution (50 mL) of the
ester 3 (10 mmol) was added a THF solution of NaN(SiMe3)2
(1 M, 11 mmol). After stirring for 1 h the reaction mixture
was cooled to -78 °C and a THF solution (30 mL) of the bis-
(imidoyl)chloride 2 (5 mmol) was slowly added by syringe (30
min). The temperature was allowed to rise to ambient and the
mixture was stirred for 2 h. The mixture was transferred to
an aqueous solution of NH4Cl (5 M, 250 mL). Addition of a
mixture of ether and THF (1:1) resulted in precipitation of the
product which was isolated by filtration, washed with ether,
dried in vacuo, and recrystallized from DMF or DMSO. Due
to the low solubility of the pigment dyes obtained, NMR data
could be obtained only for selected products. However, correct
elemental analyses were obtained in all cases. The products
can be prepared in similar yields using LDA rather than NaN-
(SiMe3)2.
1,4-Bis(p h en yl)-3,6-bisp h en ylp yr r olo[3,2-b]p yr r ol-2,5-
d ion e (4c). IR (Nujol, cm-1): ν˜ ) 1728 (s, νCO), 1640 (s, νCdC).
MS [CI (H2O), m/z (%)]: 441 (M+ + 1, 100), 74 (68). Anal. Calcd
for C30H20N2O2 (440.50): C, 81.80; H, 4.58; N, 6.36. Found:
C, 81.66; H, 4.59; N, 6.56.
1,4-Bis(p h en yl)-3,6-bis(4-tolyl)p yr r olo[3,2-b]p yr r ol-2,5-
d ion e (4d ). IR (Nujol, cm-1): ν˜ ) 1723 (s, νCO), 1639 (s, νCdC).
MS [CI (H2O), m/z (%)]: 468 (M+ + 1, 82), 103 (10), 77 (44).
Anal. Calcd for C32H24N2O2 (468.55): C, 82.03; H, 5.16; N, 5.98.
Found: C, 81.76; H, 5.18; N, 6.08.
1,4-Bis(4-tolyl)-3,6-bis[(4-d im eth yla m in o)p h en yl]p yr -
r olo[3,2-b]p yr r ol-2,5-d ion e (4p ). IR (Nujol, cm-1): ν˜ ) 1728
(s, νCO), 1651 (s, νCdC). MS [CI (H2O), m/z (%)]: 555 (M+ + 1,
100), 277 (32), 134 (19). Anal. Calcd for C36H34N4O2 (554.69):
C, 77.95; H, 6.18; N, 10.10. Found: C, 77.43; H, 5.99; N, 10.27.
1,4-Bis(4-tolyl)-3,6-bis(1-n a p h th yl)p yr r olo[3,2-b]p yr r ol-
2,5-d ion e (4q). IR (Nujol, cm-1): ν˜ ) 1739 (s, νCO), 1655 (s,
ν
CdC). MS [CI (H2O), m/z (%)]: 569 (M+ + 1, 54), 284 (100),
241 (66). Anal. Calcd for C40H28N2O2 (568.67): C, 84.48; H,
4.96; N, 4.93. Found: C, 84.14; H, 4.97; N, 5.09.
1,4-Bis(p h en yl)-3,6-bis(4-m eth oxyp h en yl)p yr r olo[3,2-
b]p yr r ol-2,5-d ion e (4e). IR (Nujol, cm-1): ν˜ ) 1728 (s, νCO),
1654 (s, νCdC). MS [CI (H2O), m/z (%)]: 501 (M+ + 1, 44), 481
(25), 241 (100). Anal. Calcd for C32H24N2O4 (500.55): C, 76.79;
H, 4.83; N, 5.60. Found: C, 76.11; H, 4.72; N, 5.67.
1,4-Bis(4-tolyl)p yr r olo[3,2-b]p yr r ol-2,5-d ion e (4f). IR
(Nujol, cm-1): ν˜ ) 1726 (s, νCO), 1647 (s, νCdC). MS [CI (H2O),
m/z (%)]: 317 (M+ + 1, 100), 158 (76), 130 (88). Anal. Calcd
for C20H16N2O2 (316.36): C, 75.93; H, 5.10; N, 8.85. Found:
C, 75.46; H, 5.37; N, 8.81.
1,4-Bis(4-tolyl)-3,6-bism eth ylp yr r olo[3,2-b]p yr r ol-2,5-
d ion e (4g). IR (Nujol, cm-1): ν˜ ) 1738 (s, νCO), 1663 (s, νCdC).
MS [CI (H2O), m/z (%)]: 345 (M+ + 1, 100), 330 (18), 91 (38).
Anal. Calcd for C22H20N2O2 (344.41): C, 76.71; H, 5.85; N, 8.13.
Found: C, 75.95; H, 5.50; N, 8.88.
1,4-Bis(4-tolyl)-3,6-bis(2-th ien yl)p yr r olo[3,2-b]p yr r ol-
2,5-d ion e (4r ). IR (Nujol, cm-1): ν˜ ) 1723 (s, VCO), 1644 (s,
ν
CdC). MS [CI (H2O), m/z (%)]: 481 (M+ + 1, 100), 212 (17), 91
(13). Anal. Calcd for C28H20N2O2S2 (480.60): C, 69.98; H, 4.19;
N, 5.83. Found: C, 69.19; H, 4.38; N, 5.95.
1,4-Bis(4-t olyl)-3,6-b is(N-m et h ylp yr r ol-2-yl)p yr r olo-
[3,2-b]p yr r ol-2,5-d ion e (4s). 1H NMR (200 MHz, CD2Cl2): δ
) 2.31 (s, 6 H, Tol-CH3), 3.16 (s, 6 H, N-CH3), 6.00 (m, 4 H,
Hetar), 6.52 (t, 2 H, J ) 2.1, Hetar), 6.95-7.06 (m, 8 H, Ar).
13C NMR (50 MHz, CD2Cl2): δ ) 21.0 (tolyl-CH3), 34.6 (N-
CH3), 98.3, 108.7, 113.6, 120.1, 121.1, 124.6, 124.8, 129.3,
130.0, 131.4, 137.3, 145.5, 170.6 (CO). IR (Nujol, cm-1): ν˜ )
1737 (s, νCO), 1657 (s, νCdC). MS [CI (H2O), m/z (%)]: 475 (M+
+ 1, 76), 241 (42), 154 (86). Anal. Calcd for C30H26N4O2
(474.56): C, 75.93; H, 5.52; N, 11.81. Found: C, 76.01; H, 5.56;
N, 11.93.
1,4-Bis(4-tolylyl)-3,6-bis-ter t-bu tylp yr r olo[3,2-b]p yr r ol-
2,5-d ion e (4h ). IR (Nujol, cm-1): ν˜ ) 1728 (s, νCO), 1632 (s,
1,4-Bis(4-tolyl)-3,6-bis(3-p yr id yl)p yr r olo[3,2-b]p yr r ol-
ν
CdC). MS [CI (H2O), m/z (%)]: 431 (M+ + 1, 42), 413 (100),
2,5-d ion e (4t). IR (Nujol, cm-1): ν˜ ) 1732 (s, νCO), 1663 (s,
385 (18). Anal. Calcd for C28H34N2O2 (430.59): C, 78.10; H,
7.96; N, 6.51. Found: C, 78.09; H, 7.44; N, 6.81.
ν
CdC). MS [CI (H2O), m/z (%)]: 471 (M+ + 1, 100), 364 (81),
207 (34). Anal. Calcd for C30H22N4O2 (470.53): C, 76.58; H,
4.71; N, 11.91. Found: C, 76.36; H, 4.59; N, 12.04.
1,4-Bis(4-t olyl)-3,6-b isb en zylp yr r olo[3,2-b]p yr r ol-2,5-
d ion e (4i). H NMR (200 MHz, DMF-d7, 90 °C): δ ) 2.39 (s, 6
H, Tol-CH3), 3.50 (s, 4 H, Benzyl-CH2), 6.89 (m, 4 H, Ar), 7.11
(m, 6 H, Ar), 7.28 (m, 8 H, Ar). 13C NMR (50 MHz, ): δ ) 20.7
(Tol-CH3), 28.6 (benzyl-CH2), 104.42, 126.6, 127.5, 128.7, 130.2,
132.7, 138.5, 139.1, 147.8, 172.3 (CO). IR (Nujol, cm-1): ν˜ )
1731 (s, νCO), 1658 (s, νCdC). MS [CI (H2O), m/z (%)]: 497 (M+
+ 1, 100), 91 (46). Anal. Calcd for C34H28N2O2 (496.61): C,
82.23; H, 5.68; N, 5.64. Found: C, 82.16; H, 5.74; N, 5.86.
1,4-Bis(4-tolyl)-3,6-bis(d im eth yla m in o)p yr r olo[3,2-b]-
p yr r ol-2,5-d ion e (4j). IR (Nujol, cm-1): ν˜ ) 1695 (s, νCO), 1663
(s, νCdC). MS [CI (H2O), m/z (%)]: 403 (M+ + 1, 100). Anal.
Calcd for C24H26N4O2 (402.50): C, 71.62; H, 6.51; N, 13.92.
Found: C, 72.59; H, 6.40; N, 13.86.
1,4-Bis(4-tolyl)-3,6-bis(4-p yr id yl)p yr r olo[3,2-b]p yr r ol-
2,5-d ion e (4u ). IR (Nujol, cm-1): ν˜ ) 1732 (s, νCO), 1663 (s,
ν
CdC). MS [CI (H2O), m/z (%)]: 471 (M+ + 1, 100), 135 (19), 91
(17). Anal. Calcd for C30H22N4O2 (470.53): C, 76.58; H, 4.71;
N, 11.91. Found: C, 76.36; H, 4.59; N, 12.04.
1,4-Bis(4-m eth oxyph en yl)-3,6-bis(4-p h en yl)p yr r olo[3,2-
b]p yr r ol-2,5-d ion e (4v). IR (Nujol, cm-1): ν˜ ) 1728 (s, νCO),
1655 (s, νCdC). MS [CI (H2O), m/z (%)]: 501 (M+ + 1, 100), 222
(61), 89 (73). Anal. Calcd for C32H24N2O4 (500.55): C, 76.79;
H, 4.83; N, 5.60. Found: C, 76.11; H, 4.88; N, 5.88.
1,4-Bis(4-n itr op h en yl)-3,6-bis(4-p h en yl)p yr r olo[3,2-b]-
p yr r ol-2,5-d ion e (4x). IR (Nujol, cm-1): ν˜ ) 1728 (s, νCO),
1639 (s, νCdC). MS [CI (H2O), m/z (%)]: 531 (M+ + 1, 17), 329
(26), 139 (100). Anal. Calcd for C30H18N4O6 (530.50): C, 67.92;
H, 3.42; N, 10.56. Found: C, 67.83; H, 3.54; N, 10.92.
1,4-Bis(4-n itr op h en yl)-3,6-bis(N-m eth ylp yr r ol-2-yl)p yr -
r olo[3,2-b]p yr r ol-2,5-d ion e (4y). IR (Nujol, cm-1): ν˜ ) 1738
(s, νCO), 1666 (s, νCdC). MS [CI (H2O), m/z (%)]: 537 (M+ + 1,
(15) Push-pull substituted heterocycles are of both theoretical and
practical interest: (a) Gompper, R.; Wagner, H.-U. Angew. Chem. 1988,
100, 1492; Angew. Chem. Int. Ed. Engl. 1988, 27, 1437. (b) Effenberger,
F.; Schlosser, H.; Ba¨uerle, P.; Maier, S.; Port, H.; Wolf, H. C. Angew.
Chem. 1988, 100, 274; Angew. Chem., Int. Ed. Engl. 1988, 27, 281.