Mlostoń Grzegorz, Celeda Małgorzata, Urbaniak Katarzyna, Jasiński Marcin, Bakhonsky Vladyslav, Schreiner Peter R, Heimgartner Heinz
Department of Organic and Applied Chemistry, University of Łódź, Tamka 12, PL-91-403 Łódź, Poland.
Justus Liebig University, Institute of Organic Chemistry, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany.
Beilstein J Org Chem. 2019 Feb 19;15:497-505. doi: 10.3762/bjoc.15.43. eCollection 2019.
Adamantyloxyamine reacts with formaldehyde to give -(adamantyloxy)formaldimine as a room-temperature-stable compound that exists in solution in monomeric form. This product was used for reactions with α-hydroxyiminoketones leading to a new class of 2-unsubstituted imidazole 3-oxides bearing the adamantyloxy substituent at N(1). Their reactions with 2,2,4,4-tetramethylcyclobutane-1,3-dithione or with acetic acid anhydride occurred analogously to those of 1-alkylimidazole 3-oxides to give imidazol-2-thiones and imidazol-2-ones, respectively. Treatment of 1-(adamantyloxy)imidazole 3-oxides with Raney-Ni afforded the corresponding imidazole derivatives without cleavage of the N(1)-O bond. Finally, the -alkylation reactions of the new imidazole -oxides with 1-bromopentane or 1-bromododecane open access to diversely substituted, non-symmetric 1,3-dialkoxyimidazolium salts. Adamantyloxyamine reacts with glyoxal and formaldehyde in the presence of hydrobromic acid yielding symmetric 1,3-di(adamantyloxy)-1-imidazolium bromide in good yield. Deprotonation of the latter with triethylamine in the presence of elemental sulfur allows the in situ generation of the corresponding imidazol-2-ylidene, which traps elemental sulfur yielding a 1,3-dihydro-2-imidazole-2-thione as the final product.
金刚烷氧基胺与甲醛反应生成N-(金刚烷氧基)甲醛亚胺，这是一种在室温下稳定的化合物，以单体形式存在于溶液中。该产物用于与α-羟基亚氨基酮反应，生成一类新型的2-未取代咪唑3-氧化物，其N(1)位带有金刚烷氧基取代基。它们与2,2,4,4-四甲基环丁烷-1,3-二硫酮或乙酸酐的反应与1-烷基咪唑3-氧化物的反应类似，分别生成咪唑-2-硫酮和咪唑-2-酮。用雷尼镍处理1-(金刚烷氧基)咪唑3-氧化物得到相应的咪唑衍生物，且N(1)-O键未断裂。最后，新的咪唑3-氧化物与1-溴戊烷或1-溴十二烷的N-烷基化反应可得到多种取代的不对称1,3-二烷氧基咪唑鎓盐。金刚烷氧基胺在氢溴酸存在下与乙二醛和甲醛反应，以良好的产率生成对称的1,3-二(金刚烷氧基)-1-咪唑鎓溴化物。在元素硫存在下，用三乙胺对后者进行去质子化，可原位生成相应的咪唑-2-亚基，该亚基捕获元素硫，生成1,3-二氢-2-咪唑-2-硫酮作为最终产物。
