Conversion of methyl ketones into terminal acetylenes: Ethynylferrocene reactant: 22.8 g (0.1 mol) of acetylferrocene solvent: 25 mL (0.32 mol) of N,N‐dimethylformamide (DMF) reactant: 25 mL (0.27 mol) of phosphorus oxychloride intermediate: (2‐formyl‐1‐chlorovinyl)ferrocene solvent: 300 mL of anhydrous 1,4‐dioxane product: ethynylferrocene

New imidazolium salts, 1-(prop-2-ynyl)-3-vinyl-3H-imidazol-1-ium bromide, 1a, the tetraphenylborate, 1b, and hexafluorophosphate, 1c, salts of 1a and 3-allyl-1-(prop-2-ynyl)-3H-imidazol-1-ium bromide, 2a, containing alkene and alkyne groups for derivatisation were prepared from commercially available starting materials and fully3a, 3b or 3c, and [{µ 2 -HCCCH 2 N᎐ ᎐ C(H)N(CH 2 CH᎐ ᎐ CH 2 )CH᎐ ᎐ CH}Co 2 (CO) 6 ]BF 4 , 4a, and a new organometallic ionic liquid, [{µ 2 -HCCCH 2 N᎐ ᎐ C(H)N(CH 2 CH᎐ ᎐ CH 2 )CH᎐ ᎐ CH}Co 2 (CO) 6 ]PF 6 , 4b, were isolated by reacting 1a-c or 2a with Co 2 (CO) 8 . The compound 4b, the first ionic liquid bearing an organometallic moiety covalently attached to the cation, melts reversibly at 75-77 ЊC without decomposition. The imidazolium protons in 1b and 3b are shielded in the 1 H NMR as a result of π-interaction with the phenyl rings of the tetraphenylborate anion. The cation-anion contacts (C-H ؒ ؒ ؒ π ∼ 2.6 Å) observed in the molecular structure of 3b in the solid state are also maintained in solution, as evidenced in NOE NMR experiments. The molecular structures of 3b and 3c show an alkyne unit bonded to a Co 2 (CO) 6 fragment with the C᎐ ᎐ ᎐ C bond perpendicular to the Co-Co bond. † This paper is based on work presented at OMCOS 8 held at Santa Barbara, USA, 6-10 August 1995. Electronic supplementary information (ESI) available: Table of ionic liquids and melting points. See

The synthesis of 5-ethynyl-2,2¢-bipyridine (9) from 5methyl-2,2¢-bipyridine (5) is reported. The conversion of the methyl derivative, which is the most common starting material to further substitution, involves the preparation of 2,2¢-bipyridine-5carbaldehyde (6). Corey-Fuchs olefination and subsequent hydrolysis yields the target compound 9. The multistep synthesis is discussed with respect to alternative routes and compared with those of related 4-substituted 2,2¢-bipyridines.

No abstract