Journal article

Publication year: 2019

Pages: 497-505

Journal: Beilstein Journal of Organic Chemistry

Volume number: 15

ISSN: 1860-5397

Open access status: Gold

DOI Link: https://doi.org/10.3762/bjoc.15.43

Publisher: Beilstein-Institut

Abstract: 
Adamantyloxyamine reacts with formaldehyde to give N-(adamantyloxy)formaldimine as a room-temperature-stable compound that exists in solution in monomeric form. This product was used for reactions with alpha-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-tetramethylcy-clobutane-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 O-alkylation reactions of the new imidazole N-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)-1H-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-2H-imidazole-2-thione as the final product.

Harvard Citation style: Mloston, G., Celeda, M., Urbaniak, K., Jasinski, M., Bakhonsky, V., Schreiner, P., et al. (2019) Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts, Beilstein Journal of Organic Chemistry, 15, pp. 497-505. https://doi.org/10.3762/bjoc.15.43

APA Citation style: Mloston, G., Celeda, M., Urbaniak, K., Jasinski, M., Bakhonsky, V., Schreiner, P., & Heimgartner, H. (2019). Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts. Beilstein Journal of Organic Chemistry. 15, 497-505. https://doi.org/10.3762/bjoc.15.43