- Efficient Catalysts of Acyclic Guanidinium Iodide for the Synthesis of Cyclic Carbonates from Carbon Dioxide and Epoxides under Mild Conditions
-
We have studied the synthesis of five-membered cyclic carbonates through the cycloaddition of CO 2 to epoxides by using acyclic guanidinium salts. We have found that the cycloaddition reactions proceed smoothly at ordinary temperatures and pressures and result in good yields when acyclic guanidinium iodides are employed as catalysts. Both cation moiety and anion moiety of the guanidinium salts play important roles in their catalytic activity. It is essential to have active hydrogens on the cation moiety as well as an iodide ion as the anion moiety so as to achieve good catalytic activity. Guanidinium iodides with three or more active hydrogens give cyclic carbonates in high yields in polar solvents such as 1-methylpyrrolidin-2-one, whereas the guanidinium iodides with one or two active hydrogens show good catalytic activity in less polar solvents such as 2-methyltetrahydrofuran.
- Aoyagi, Naoto,Endo, Takeshi,Furusho, Yoshio
-
p. 150 - 158
(2019/12/26)
-
- Synthesis and biological activity of analogues of the antidiabetic/antiobesity agent 3-guanidinopropionic acid: Discovery of a novel aminoguanidinoacetic acid antidiabetic agent
-
3-Guanidinopropionic acid (1, PNU-10483) has been demonstrated to both improve insulin sensitivity and to promote weight loss selectively from adipose tissue in animal models of non-insulin-dependent diabetes mellitus (NIDDM). However, 1 has also been shown to be a substrate for both the creatine transporter and creatine kinase, leading to marked accumulation in muscle tissue as the corresponding N-phosphate 4. In an effort to identify novel entities that maintain antidiabetic potency without susceptibility to creatine-like metabolism, an analogue program was undertaken to explore the effects of various structural modifications, including homologation, simple substitution, single atom mutations, and bioisosteric replacements for the guanidine and carboxylic acid. Overall, the scope of activity encompassed by the set of new analogues proved to be exceedingly narrow. Notable exceptions demonstrating equivalent or improved antidiabetic activity included the α-amino derivative 29, aminopyridine 47, isothiourea 67, and aminoguanidine 69. On the basis of its superior therapeutic ratio, aminoguanidine 69 was selected for preclinical development and became the foundation for a second phase of analogue work. Furthermore, in vitro studies demonstrated that 69 is markedly less susceptible to phosphorylation by creatine kinase than the lead 1, suggesting that it should have less potential for accumulation in muscle tissue than 1.
- Larsen,Connell,Cudahy,Evans,May,Meglasson,O'Sullivan,Schostarez,Sih,Stevens,Tanis,Tegley,Tucker,Vaillancourt,Vidmar,Watt,Yu
-
p. 1217 - 1230
(2007/10/03)
-
- 1,3-Disubstituted benzazepines as neuropeptide Y Y1 receptor antagonists
-
A novel class of potent and selective non-peptide neuropeptide Y (NPY) Y1 receptor antagonists, having benzazepine nuclei, have been designed, synthesized, and evaluated for activity. Through a blind screening we found the compound 1-N-(3-(N' -(tert-butoxycarbonyl)amino)benzyl)-7-methoxy-3-(3)-methylureido)-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one (9: IC50 =1.6 μM). Chemical modifications of 9 gave a potent NPY Y1 antagonist 3-(N-(4-hydroxyphenyl)-N0 -methylguanidino)-1-N-(3-(N'-(tert- butoxycarbonyl)amino)benzyl)-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one (14c: IC50 =43 nM), which had no affnity for NPY Y2 and Y5 receptors. (C) 1999 Elsevier Science Ltd. All rights reserved.
- Murakami, Yasushi,Hagishita, Sanji,Okada, Tetsuo,Kii, Makoto,Hashizume, Hiroshi,Yagami, Tatsuroh,Fujimoto, Masafumi
-
p. 1703 - 1714
(2007/10/03)
-
- Inhibitors of human nitric oxide synthase isoforms with the carbamidine moiety as a common structural element
-
Identification of potent and selective inhibitors of inducible nitric oxide synthase (NOS) is of great interest because of their therapeutic potential for treatment of diseases mediated by excess production of nitric oxide. We present here a comparison of
- Moore, William M.,Webber, R. Keith,Fok, Kam F.,Jerome, Gina M.,Kornmeier, Christine M.,Tjoeng, Foe S.,Currie, Mark G.
-
p. 1559 - 1564
(2007/10/03)
-