A novel tautomerism in alkyl dihydropyrimidines : observation of tautomerism by H-D exchange of 2- and/or 4-methyl protons of dihydropyrimidines in CD3OD
作者:Yong Hae Kim、Byoung Uk Lim
DOI:10.1016/s0040-4039(00)78907-6
日期:1991.4
A novel tautomerism was found in dihydropyrimidines such as 2-amino-4,6,6-trimethyldihydropyrimidine 1 and 2,4,6,6-tetramethyldihydropyrimidine 2 by the observation of H-D exchange on both 4-methyl protons of 1 and 2,4-dimethyl protons of 2 by the treatment of 1 and 2 with CD3OD in the absence of base under mild conditions.
Development of inhibitors of heterotrimeric Gαi subunits
作者:Kathryn M. Appleton、Kevin J. Bigham、Christopher C. Lindsey、Starr Hazard、Jonel Lirjoni、Stuart Parnham、Mirko Hennig、Yuri K. Peterson
DOI:10.1016/j.bmc.2014.04.035
日期:2014.7
Heterotrimeric G-proteins are the immediate downstream effectors of G-protein coupled receptors (GPCRs). Endogenous protein guanine nucleotide dissociation inhibitors (GDIs) like AGS3/4 and RGS12/14 function through GPR/Goloco GDI domains. Extensive characterization of GPR domain peptides indicate they function as selective GDIs for G alpha(i) by competing for the GPCR and G beta gamma and preventing GDP release. We modified a GPR consensus peptide by testing FGF and TAT leader sequences to make the peptide cell permeable. FGF modification inhibited GDI activity while TAT preserved GDI activity. TAT-GPR suppresses G-protein coupling to the receptor and completely blocked alpha(2)-adrenoceptor (alpha(2)AR) mediated decreases in cAMP in HEK293 cells at 100 nM. We then sought to discover selective small molecule inhibitors for G alpha(i). Molecular docking was used to identify potential molecules that bind to and stabilize the G alpha(i)-GDP complex by directly interacting with both G alpha(i) and GDP. G alpha(i)-GTP and G alpha(q)-GDP were used as a computational counter screen and G alpha(q)-GDP was used as a biological counter screen. Thirty-seven molecules were tested using nucleotide exchange. STD NMR assays with compound 0990, a quinazoline derivative, showed direct interaction with G alpha(i). Several compounds showed G alpha(1) specific inhibition and were able to block alpha(2)AR mediated regulation of cAMP. In addition to being a pharmacologic tool, GDI inhibition of G alpha subunits has the advantage of circumventing the upstream component of GPCR-related signaling in cases of over-stimulation by agonists, mutations, polymorphisms, and expression-related defects often seen in disease. (C) 2014 Elsevier Ltd. All rights reserved.
Kim, Yong Hae; Yoon, Cheol Min; Lee, Nam Jin, Heterocycles, 1981, vol. 16, # 1, p. 49 - 52
作者:Kim, Yong Hae、Yoon, Cheol Min、Lee, Nam Jin
DOI:——
日期:——
�ber cyclische Guanidin?Mesityloxid- und Guanidin?Phoron-Kondensate
作者:W. Wendelin、A. Harler
DOI:10.1007/bf00912609
日期:——
�ber die Reaktionen von monosubstituierten Guanidinen mit ?,?-unges�ttigten Ketonen