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Preparation of uracil by cycloreversion. Structure of cycloalkane/ene‐ and norbornane/ene‐fused dihydrouracils
Author(s) -
FrimpongManso Samuel,
Nagy Katalin,
Stájer Géza,
Bernáth Gábor,
Sohár Pál
Publication year - 1992
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570290140
Subject(s) - norbornane , chemistry , cycloalkane , cycloalkene , norbornene , ene reaction , cyclohexane , dicyclopentadiene , monobasic acid , organomercury compounds , organic chemistry , catalysis , copolymer , polymer , metal , polymerization
The reactions of the 2‐amino‐1‐cycloalkane‐, cycloalkene‐, norbornane‐ and norbornenecarboxylates 1–9 with potassium cyanate gave urea esters, which were cyclized to cycloalkane‐, cycloalkene‐, norbornane‐ and norbornene‐fused 5,6‐dihydrouracils 10–17 . On cyclization, the urea ester formed from trans ‐4‐cyclohexene‐1‐carboxylate, furnished the cis ‐fused 5,6‐dihydropyrimidine‐2,4(1 H ,3 H )‐dione. On heating, the norbornene‐ diexo ‐fused dihydrouracil 16 yielded 2,4‐pyrimidinedione through the splitting‐off of cyclopentadiene. The structures of the compounds were proved by 1 H and 13 C nmr spectroscopy.