We developed a chromium-catalyzed, photochemical, and linear-selective alkylation of aldehydes with alkylzirconium species generated in situ from a wide range of alkenes and Schwartz’s reagent. Photochemical homolysis of the C–Zr bond afforded alkyl radicals, which were then trapped by a chromium complex catalyst to generate the alkylchromium(III) species for polar addition to aldehydes. The reaction
Quinones. 4. Novel eicosanoid antagonists: synthesis and pharmacological evaluation
作者:Mitsuru Shiraishi、Kaneyoshi Kato、Shinji Terao、Yasuko Ashida、Zenichi Terashita、Go Kito
DOI:10.1021/jm00129a030
日期:1989.9
A new series of omega-phenyl-omega-quinonylalkanoic acids and related compounds was synthesized. The compounds were tested for their inhibitory effects on U-44069-induced contraction of the rabbit aorta. (+/- )-7-(3,5,6-Trimethyl-1,4-benzoquinon-2-yl)-7-phenylheptanoic acid (4d) (AA-2414) with pA2 value of 8.28 was one of the most potent compounds. Compound 4d inhibited U-46619-induced contraction of the guinea pig lung (pA2 = 8.29) and U-44069-induced aggregation of the guinea pig platelet (IC50 = 3.5 x 10(-7) M). Compound 4d displaced the binding of [3H]U-46619 to guinea pig platelets (IC50 = 7.4 x 10(-9) M). Compound 4d also showed very potent inhibitory effects with an MED of 0.3 mg/kg (po) on U-46619-, LTD4-, PAF-, or IgG1-induced bronchoconstriction in guinea pigs. The enantiomers of 4d were prepared. The R-(+) isomer 8a was active in both in vitro and in vivo tests, but the S-(-) isomer 8b was much less active. We concluded that the antiasthmatic effects of 4d were based mainly on the TXA2 receptor antagonistic action. In addition, compound 4d showed potent inhibitory effects on PGD2-, PGF2 alpha-, and 11-epi-PGF2 alpha-induced contraction of the guinea pig tracheal strips. The diverse inhibitory effects might be expressed in terms of eicosanoid-antagonistic activity.
Takai–Utimoto reactions of oxoalkylhalides catalytic in chromium and cobalt
作者:Ludger A. Wessjohann、Henri S. Schrekker
DOI:10.1016/j.tetlet.2007.04.119
日期:2007.6
The scope of chromium(II)/cobalt(I)-catalyzed Takai-Utimoto reactions was extended to substrates with unprotected reactive functional groups. In the presence of a higher chlorosilane and manganese the first chromium(II)/cobalt(I) -catalyzed version for the coupling of oxoalkylhalides with aldehydes resulted. (c) 2007 Elsevier Ltd. All rights reserved.
Piva Olivier, Amougay Aiecha, Pete Jean-Pierre, Synth. Commun, 25 (1995) N 2, S 219-226