Saturated heterocycles, 248. Synthesis of 2,4-dioxo and 4-oxo-2-thioxo derivatives of octahydrocyclopenta[d]pyrimidines

✍ Scribed by Ferenc Fülöp; Zsolt Szakonyi; Gábor Bernáth; Pál Sohár

• Book ID: 102338311
• Publisher: Journal of Heterocyclic Chemistry
• Year: 1997
• Tongue: English
• Weight: 472 KB
• Volume: 34
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570340419

✦ Synopsis

Abstract

Unsubstituted and 1‐benzyl‐substituted cis‐cyclopenta[d]pyrirnidine‐2,4‐diones and cis‐2‐thioxo‐cyclopenta[d]pyrimidin‐4‐ones 9a,b and 10a,b were prepared from the corresponding cis‐2‐amino‐1‐cyclopentanecarboxylates 3 and 5 with potassium cyanate and thiocyanate. It was found that the cis derivatives 7a‐h readily underwent ring closure, resulting in 3‐substituted cis‐2,4‐cyclopenta[d]pyrimidinediones and cis‐2‐thioxocyclopenta[d]pyrimidin‐4‐ones 11a‐d and 12a‐d, whereas the trans counterparts 8a‐d failed to cyclize, but gave hydrolysed amino acid derivatives 13a,b and 14. This difference in the reactivities of the cis and trans isomers is a further example of the difficulty of preparing cyclopentane trans‐fused six‐membered 1,3‐heterocycles by ring closure.