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Nitration of 2,3′‐bithienyl
Author(s) -
Dell'Erba Carlo,
Guanti Giuseppe,
Garbarino Giacomo
Publication year - 1974
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570110630
Subject(s) - nitration , acetic anhydride , chemistry , nitric acid , acetic acid , nitro , electrophile , organic chemistry , medicinal chemistry , catalysis , alkyl
The nitration of 2,3′‐bithienyl ( 1 ) with fuming nitric acid in acetic anhydride at 0° gives a mixture of 3‐nitro‐ ( 2 ), 2′ ‐nitro‐ ( 3 ) and 5‐nitro‐2,3′‐bithienyl ( 4 ) with relative percentages of 38.7%, 34.8% and 26.5%. When the nitration of 1 was carried out with fuming nitric acid in acetic acid at 20°, the same compounds 2, 3 and 4 were obtained, but with different relative percentages: 20.4%, 36.5% and 43.1% respectively. The results of the mononitration of 1 are compared with those obtained in other electrophilic substitutions and with the theoretical predictions. The further nitrations of 2, 3 and 4 with nitric acid in acetic anhydride at room temperature lead to the formation of five dinitro‐2,3′‐bithienyl isomers. Compound 2 gives a mixture of 2′,3‐dinitro‐ ( 5 ) and 3,5′‐dinitro‐2,3′‐bithienyl ( 6 ); compound 3 gives a mixture of 5 , 2′,5‐dinitro‐ ( 7 ) and 2′,4‐dinitro‐2,3′‐bithienyl ( 8 ); compound 4 gives 7 and 5,5′‐dinitro‐2,3′‐bithienyl ( 9 ). The possible reasons of the formation of the various dinitro‐2,3′‐bithienyl isomers are discussed.