Reference

Palladium-catalyzed intramolecular CH arylation of five-membered N-heterocycles

All Rights Reserved. Palladium-catalyzed intramolecular CH arylation of five-membered N-heterocycles. Arai, Nobumichi; Takahashi, Masabumi; Mitani, Makoto; Mori, Atsunori (Chemical Resources Laboratory, Tokyo Institute of Technology 4259 Nagatsuta, Yokohama 226-8503, Japan). Synlett, (18), 3170-3172 (English) 2006 Georg Thieme Verlag. CODEN: SYNLES. ISSN: 0936-5214.In this article, certain chemicals are used. One of their cas registry numbers is 109-97-7 DOCUMENT TYPE: Journal CA Section: 28 (Heterocyclic Compounds (More Than One Hetero Atom)) Intramol. CH arylation of imidazole derivs. is carried out in the presence of a palladium catalyst to form fused heteroarom. compds. The reaction of imidazole with 2-iodobenzyl bromide with NaH gives the cyclization precursor in an excellent yield. This then undergoes a palladium-catalyzed intramol. CH arylation at 100 °C to form 5H-imidazo[5,1-a]isoindole in 78% yield. .

Experimental and Theoretical Studies on the Nature of Weak Nonbonded Interactions between Divalent Selenium and Halogen Atoms

Experimental and Theoretical Studies on the Nature of Weak Nonbonded Interactions between Divalent Selenium and Halogen Atoms. Iwaoka, Michio; Katsuda, Takayuki; Komatsu, Hiroto; Tomoda, Shuji ( Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo 153-8902, Japan). Journal of Organic Chemistry, 70(1), 321-327 (English) 2005 American Chemical Society. CODEN: JOCEAH. ISSN: 0022-3263. DOCUMENT TYPE: Journal CA Section: 22 (Physical Organic Chemistry) To investigate the nature of weak nonbonded selenium×××halogen interactions (Se×××X interactions; X = F, Cl, and Br), three types of model compds. [2-(CH2X)C6H4SeY (1-3), 3-(CH2X)-2-C10H6SeY (4-6), and 2-XC6H4CH2SeY (7-9); Y = CN, Cl, Br, SeAr, and Me] were synthesized, and their 77Se NMR spectroscopic behaviors were analyzed in CDCl3. The gradual upfield shifts of 77Se NMR absorptions obsd. for series 1-3 and 4-6 suggested that the strength of Se×××X interaction decreases in the order of Se×××F > Se×××Cl > Se×××Br. The quantum chem. calcns. at the B3LYP/631H level using the polarizable continuum model (PCM) revealed that the most stable conformer for 1-3 is the one with an intramol. short Se×××X at. contact in CHCl3 (e = 4.9) and also that the nX ? s*Se-Y orbital interaction (ESe×××X) can reasonably explain the order of strength for the Se×××X interactions. On the other hand, the 77Se NMR absorptions obsd. for series 7-9 did not shift significantly from the ref.There are some commonly used reagents with their cas registry numbers 3433-80-5 and 448193-23-5 in this article. compds. (C6H5CH2SeY), indicating the absence of the Se×××X interaction for 7-9 presumably due to attenuation of basicity for the halogen atom that is substituted directly to the arom. ring. These observations suggested that the nX ? s*Se-Y orbital interaction is a dominant factor for formation of weak Se×××X interactions. Electron correlation was also suggested to be important for the stability. .