Discovery of Juniperus sabina var. balkanensis R. P. Adams and A. N. Tashev in western Turkey (Anatolia)

Additional analyses of trnS-trnG and nrDNA from herbarium specimens from Europe revealed the presence of J. sabina var. balkanensis in western Turkey near Izmir and expands the range previously known only from Bulgaria and adjacent mountains in Greece. A more detailed map of the taxon\u27s distribution is presented

2-Unsubstituted Imidazole N-Oxides as Novel Precursors of Chiral 3-Alkoxyimidazol-2-ylidenes Derived from trans-1,2-Diaminocyclohexane and Other Chiral Amino Compounds

‘Desymmetrization’ of trans-1,2-diaminocyclohexane by treatment with α,ω-dihalogenated alkylation reagents leads to mono-NH2 derivatives (‘primary-tertiary diamines’). Upon reaction with formaldehyde, these products formed monomeric formaldimines. Subsequently, reactions of the formaldimines with α-hydroxyiminoketones led to the corresponding 2-unsubstituted imidazole N-oxide derivatives, which were used here as new substrates for the in situ generation of chiral imidazol-2-ylidenes. Upon O-selective benzylation, new chiral imidazolium salts were obtained, which were deprotonated by treatment with triethylamine in the presence of elemental sulfur. Under these conditions, the intermediate imidazol-2-ylidenes were trapped by elemental sulfur, yielding the corresponding chiral non-enolizable imidazole-2-thiones in good yields. Analogous reaction sequences, starting with imidazole N-oxides derived from enantiopure primary amines, amino alcohols, and amino acids, leading to the corresponding 3-alkoxyimidazole-2-thiones were also studied