Selective monolithiation of 2,5-dibromopyridine with butyllithium

Luminescence and Single‐Molecule‐Magnet Behaviour in Lanthanide Coordination Complexes Involving Benzothiazole‐Based Tetrathiafulvalene Ligands

“…The precursors Ln(hfac) 3 ·2H 2 O, Ln(tta) 3 ·2H 2 O, [57,58] [43] 4,5-(ethylenedithio)tetrathiafulvalene [59] and 2-(5-bromopyridin-2-yl)-1,3-benzothiazole, [60,61] were synthesized by previously reported methods. All other reagents were purchased from Aldrich Co., Ltd. and used without further purification.…”

Recommendable Routes to Trifluoromethyl‐Substituted Pyridine‐ and Quinolinecarboxylic Acids

“…When 2,5-dibromopyridine was treated with butyllithium in toluene, halogen/metal permutation occurred regioselectively at the 2-position. [23] The 5-bromo-2-pyridinecarboxylic acid (64%) obtained upon carboxylation was converted into 5-bromo-2-(trifluoromethyl)pyridine (33%) by use of sulfur tetrafluoride. The 6-trifluoromethyl-3-pyridinecarboxylic acid (3; 85%) was again prepared by application of the halogen/metal permutation and carboxylation sequence to 5-bromo-2-(trifluoromethyl)pyridine.…”

“…The 6-trifluoromethyl-3-pyridinecarboxylic acid (3; 85%) was again prepared by application of the halogen/metal permutation and carboxylation sequence to 5-bromo-2-(trifluoromethyl)pyridine. The latter compound was in turn made from 2,5-dibromopyridine, either through the 5-bromo-2-pyridinecarboxylic acid (by selective bromine/lithium exchange [23] ), which was then treated with sulfur tetrafluoride (21% overall) or through 5-bromo-2-iodopyridine, which was then subjected to a halogen/trifluoromethyl displacement (60% overall [16] ). In the same way, 6-trifluoromethyl-2-pyridinecarboxylic acid (4; 87%) was obtained from 2-bromo-6-(trifluoromethyl)pyridine, which was in turn derived from 2-bromo-6-iodopyridine by trifluoromethylating displacement of iodine.…”

Bis(oxazoline) Lewis Acid Catalyzed Aldol Reactions of Pyridine N‐Oxide Aldehydes—Synthesis of Optically Active 2‐(1‐Hydroxyalkyl)pyridine Derivatives: Development, Scope, and Total Synthesis of an Indolizine Alkaloid

“…Deprotection gave the pure product as yellow solid (1.05 g, 83 % yield). 1 (5-Bromopyridin-2-yl)methanol: [34] A 1.6 m solution of nBuLi in hexane (25.1 mmol, 15.7 mL) was added dropwise to a solution of 2,5-dibromopyridine (5 g, 21.1 mmol) in toluene (200 mL) at À78 8C. After 2 h of stirring a mixture of DMF (2 mL) and toluene (5 mL) was added, and the solution was stirred for 1 h at À78 8C and then warmed to À10 8C.…”