Mesoionic xanthine analogs: antagonists of adenosine receptors
摘要:
A variety of mesoionic xanthines including mesoionic thiazolo[3,2-alpha]pyrimidines, benzothiazolopyrimidines, and 1,3,4-thiadiazolo[3,2-alpha]pyrimidines were antagonists of A1-adenosine receptors (inhibition of binding of [3H]-cyclohexyladenosine) and A2-adenosine receptors (inhibition of 2-chloroadenosine-elicited accumulations of cyclic AMP) in brain tissue. Most of the compounds were less potent than theophylline and none were remarkably selective for A1- or A2-adenosine receptors. However, members of the thiadiazolopyrimidine class of mesoionics exhibited very low or no activity as antagonists of A2-adenosine receptors while exhibiting activity only 2-4-fold lower than that of theophylline at A1-adenosine receptors. Unlike the case for theophylline, the presence of a phenyl substituent in the five-membered ring did not enhance the potency of a mesoionic thiadiazolopyrimidine. The nature of the substituents on the mesoionic ring did not appear to have marked effects on potency unlike the marked effect of the nature of 1,3-substituents on activity of nonmesoionic xanthines. The benzothiazolo[3,2-alpha]pyrimidines were the most potent antagonists, being nearly as potent as theophylline at A1-adenosine receptors and somewhat more potent than theophylline at A2-adenosine receptors.
Mesoionic isoxazolo[2,3-<i>a</i>]pyrimidinediones and 1,3,4-oxadiazolo[3,2-<i>a</i>]pyrimidinediones as potential adenosine antagonists
作者:Ihsan A. Shehata、Richard A. Glennon
DOI:10.1002/jhet.5570240511
日期:1987.9
Several derivatives of two novel mesoionic ring systems, i.e., isoxazolo[2,3-a]pyrimidinedione and 1,3,4-oxadiazolo[3,2-a]pyrimidinedione, were prepared for evaluation as adenosineantagonists. Whereas both ring systems are relatively stable when the 6-position (i.e., that position corresponding to the purine 1-position) is substituted by an alkyl group, neither ring system is stable when this position
制备了两种新颖的介电环系统的几种衍生物,即异恶唑并[2,3- a ]嘧啶二酮和1,3,4-恶二唑并[3,2- a ]嘧啶二酮,作为腺苷拮抗剂进行评价。当6-位(即对应于嘌呤1-位的那个位置)被烷基取代时,两个环系统都相对稳定,而当该位置未被取代时,两个环系统都不是稳定的。6-未取代的非内消旋异恶唑并嘧啶二酮的实例表现出相似的行为。作为腺苷拮抗剂,发现中离子化合物的效力不及之前评估的中离子噻二唑[3,2- a ]嘧啶二酮类似物。
Mesoionic purinone analogs. III. The synthesis and properties of mesoionic thiazolo[3,2-<i>a</i>] pyrimidine-5,7-diones
作者:R. A. Coburn、R. A. Glennon
DOI:10.1002/jhet.5570100412
日期:1973.8
A number of mesoionicthiazolo[3,2-a ]pyrimidine-5,7-diones, isoconjugate mesoionicanalogs of xanthinc, were prepared by the condensation of 2-alkylaminothiazoles with bis(2,4,6-trichloro-phenyl)malonate esters. The ground state molecular properties and reactions of these compounds were found to be consistent with predictions based upon previous SCF molecular orbital treatments of the π-systems of
通过将2-烷基氨基噻唑与双(2,4,6-三氯-苯基)丙二酸酯缩合制备许多介电的噻唑并[3,2 - a ]嘧啶-5,7-二酮,x吨的同共轭介电类似物。 。发现这些化合物的基态分子性质和反应与基于这些类似物的π系统的先前SCF分子轨道处理的预测一致。
Mesoionic purinone analogs. 7. In vitro antibacterial activity of mesoionic 1,3,4-thiadiazolo[3,2,-a]pyrimidine-5,7-diones
作者:Robert A. Coburn、Richard A. Glennon、Zdzislaw F. Chmielewicz
DOI:10.1021/jm00255a029
日期:1974.9
SHEHATA, IHSAN A.;GLENNON, RICHARD A., J. HETEROCYCL. CHEM., 24,(1987) N 5, 1291-1295