15 π-Conjugated Polymers Incorporating Naphthalene-Based …
543
15.2 Synthesis of Naphthalene-Based Nitrogen-Containing
Heteroaromatic Rings
Naphtho[1,2-c:5,6-c
]bis[1,2,5]thiadiazole (NTz), the most well studied
naphthalene-based nitrogen-containing heteroaromatic, was first synthesized
by Mataka et al. (1991). They reported the reaction of tetrasulfur tetranitride (N4S4)
with various naphthalenols and successfully obtained NTz and its isomers. However,
due to the fact that N4S4 is an explosive compound (Villena-Blanco and Jolly 1967),
this synthetic methodology is not scalable. An alternative synthesis of NTz was
developed (Scheme 15.1) in which 1,5-dinitro-2,6-diaminonaphthalene (1) was
reduced to give 1,2,5,6-tetraaminonaphthalene (2) (Imai et al. 1973), which was
then reacted with thionyl chloride to afford NTz via cyclization. Furthermore, 2
could also undergo cyclization to form other naphthalene-based nitrogen-containing
heteroaromatics. The use of seleninyl chloride, sodium nitrite, and α-diketones as
the cyclization reagent for 2 provided naphtho[1,2-c:5,6-c
]bis[1,2,5] selenadiazole
(NSz) (Kawashima et al. 2015a), naphtho[1,2-c:5,6-c
]bis-1H-[1,2,3]triazole (3)
NaClO, KOH, TBAB
N
O
N
N
O
N
NH 2 OH•HCl, KOH
1
NOz
N
O
N
N
O
N
N
O
N
N
O
N
N
O
N
N
O
N
CH 2 Cl 2 , H 2 O
EtOH, H 2 O
4
O
O
O
O
O
O
53% in two steps
H 2 N
NH 2
NO 2
O 2 N
2
H 2 N
NH2
NH 2
H2N
•4HCl
SeOCl 2
Pyridine
N
Se
N
N
Se
N
NSz
ii) HCl
i) Raney-Ni, H 2
/CH 3 COOH
70%
68%
SOCl 2
Pyridine
60%
N
S
N
N
S
N
NTz
NH
N
N
N
N
NH
N
N
N
N
R
R
R
R
N
N
N
N
N
N
R
R
NaNO 2
AcOH, H 2 O
t BuOK, R-Br
MeOH
O
O
R
R
3
TZNT
NPz
88%
16%
AcOH, EtOH,
H 2 O
61%
Scheme 15.1 Synthesis of naphthalene-based nitrogen-containing heteroaromatic rings
543
15.2 Synthesis of Naphthalene-Based Nitrogen-Containing
Heteroaromatic Rings
Naphtho[1,2-c:5,6-c
]bis[1,2,5]thiadiazole (NTz), the most well studied
naphthalene-based nitrogen-containing heteroaromatic, was first synthesized
by Mataka et al. (1991). They reported the reaction of tetrasulfur tetranitride (N4S4)
with various naphthalenols and successfully obtained NTz and its isomers. However,
due to the fact that N4S4 is an explosive compound (Villena-Blanco and Jolly 1967),
this synthetic methodology is not scalable. An alternative synthesis of NTz was
developed (Scheme 15.1) in which 1,5-dinitro-2,6-diaminonaphthalene (1) was
reduced to give 1,2,5,6-tetraaminonaphthalene (2) (Imai et al. 1973), which was
then reacted with thionyl chloride to afford NTz via cyclization. Furthermore, 2
could also undergo cyclization to form other naphthalene-based nitrogen-containing
heteroaromatics. The use of seleninyl chloride, sodium nitrite, and α-diketones as
the cyclization reagent for 2 provided naphtho[1,2-c:5,6-c
]bis[1,2,5] selenadiazole
(NSz) (Kawashima et al. 2015a), naphtho[1,2-c:5,6-c
]bis-1H-[1,2,3]triazole (3)
NaClO, KOH, TBAB
N
O
N
N
O
N
NH 2 OH•HCl, KOH
1
NOz
N
O
N
N
O
N
N
O
N
N
O
N
N
O
N
N
O
N
CH 2 Cl 2 , H 2 O
EtOH, H 2 O
4
O
O
O
O
O
O
53% in two steps
H 2 N
NH 2
NO 2
O 2 N
2
H 2 N
NH2
NH 2
H2N
•4HCl
SeOCl 2
Pyridine
N
Se
N
N
Se
N
NSz
ii) HCl
i) Raney-Ni, H 2
/CH 3 COOH
70%
68%
SOCl 2
Pyridine
60%
N
S
N
N
S
N
NTz
NH
N
N
N
N
NH
N
N
N
N
R
R
R
R
N
N
N
N
N
N
R
R
NaNO 2
AcOH, H 2 O
t BuOK, R-Br
MeOH
O
O
R
R
3
TZNT
NPz
88%
16%
AcOH, EtOH,
H 2 O
61%
Scheme 15.1 Synthesis of naphthalene-based nitrogen-containing heteroaromatic rings