Competitive Addition of Carbon, Sulfur and Nitrogen Nucleophiles to Quaternized Heteroaromatic Compounds in Liquid Ammonia

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Journal of Organic Chemistry, ISSN: 1520-6904, Vol: 41, Issue: 8, Page: 1308-1313

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Citations 26
Citation Indexes 26
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Zoltewicz, John A.; Helmick, Larry S.; O'Halloran, John K.
American Chemical Society (ACS)
Chemistry; Nucleophiles; heteroaromatic compounds
article description
Nitromethide and ethanethiolate ions when present as ammonium salts in liquid ammonia add to the 4 position of 1-methylpyridinium ion. Each anion adds to the 4 positions of 3-iodo- and 3-cyano-1-methylpyridinium ions, to the 6 position of 1,2,5-trimethylpyrazinium ion, and to the 1 positions of 2-benzylisoquinolinium and 2-benzylphthalazinium ions. Carbanion addition to the 4 position of 3-substituted 1-methylpyridinium ions having CH, CONH, COCH, COCH, and CF substituents and to the 2 position of 3-methoxy-1-methylpyridinium ion also was observed. Carbanion addition is complete except with the 1-methyl-, 1,3-dimethyl-, and 1-methyl-3-methoxypyridinium and 2-benzylphthalazinium ions; aromatic starting material is present in the case of the pyridinium ions while 1-amino adduct is present in the phthalazinium ion case. Amino and not carbon adducts are detected for 3-chloro- and 3-carbamoyl-1-methylpyrazinium ions. Thiolate ion adds to the 4 and 6 positions of 3-acetyiand 3-carbomethoxy-1-methylpyridinium ions to give mixtures. 3-Carbamoyl-1-methylpyridinium ion adds thiolate ion at the 4 and 6 positions; interconversion is fast enough to make the mixture appear by NMR as a single adduct. Thiolate ion addition is complete except in the cases of 1-methyl- and 1-methyl-3-methoxypyridinium ions. © 1976, American Chemical Society. All rights reserved.