The condensations of 2-c~ rbethouycyclopentanone (111) with guanidine, thiourea and 2- methyl-2-thiopseudourea led to 2-amino-4-hydroxy-(IV), 4-hydrouy-2-mercapto-(XX) and 4- hydroxy-2-(methylthio)-5, G-trimethq. lenepyrimidine (XXIX), respectively. Compounds I\-, XX and XXIX mere converted to a variety of substituted 4, 5-trimethylenepyriniidines, several of which are closely related structurally to biologically important purines.
![2-氨基-6,7-二氢-5H-环戊[d]嘧啶-4-醇结构式](https://image.chemsrc.com/caspic/129/33081-06-0.png)
![2,4-diazabicyclo[4.3.0]nona-3,10-diene-5-thione结构式](https://image.chemsrc.com/caspic/006/6014-10-4.png)
![3-amino-2,4-diazabicyclo[4.3.0]nona-3,10-diene-5-thione结构式](https://image.chemsrc.com/caspic/345/5466-44-4.png)
