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Pyrimidine (C 4 H 4 N 2; / p ɪ ˈ r ɪ. m ɪ ˌ d iː n, p aɪ ˈ r ɪ. m ɪ ˌ d iː n /) is an aromatic, heterocyclic, organic compound similar to pyridine (C 5 H 5 N). [3] One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ring.
Regions of the Greek islands. Greece has many islands, [Note 1] with estimates ranging from somewhere around 1,200 [1] to 6,000, [2] depending on the minimum size to take into account. The number of inhabited islands is variously cited as between 166 [3] and 227. [2] The largest Greek island by both area and population is Crete, located at the ...
Aegean Sea with island groups Extent of the Aegean Sea. This is a list of Aegean Islands, which includes the English, Modern Greek, Ancient Greek, Latin, Medieval Latin, and Italian names for these islands in the Aegean Sea arranged by island group.
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Purine is a heterocyclic aromatic organic compound that consists of two rings (pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines and their tautomers. They are the most widely occurring nitrogen-containing heterocycles in nature. [1]
Pyrimidone is the name given to either of two heterocyclic compounds with the formula C 4 H 4 N 2 O: 2-pyrimidone and 4-pyrimidone. The compounds can also be called 2-hydroxypyrimidine or 4-hydroxypyrimidine respectively, based on a substituted pyrimidine , or 1,3- diazine , ring.
Left: The structure of pyrimidine with the locants for ring atoms marked. Right : 5-Fluorouracil , a fluoropyrimidine formally named as 5-fluoro-1 H ,3 H -pyrimidine-2,4-dione Fluoropyrimidines are a general class organic compounds in which the substituent (s) around a pyrimidine ring include at least one fluorine atom.
The systematic name for the pyridine derivatives is pyridinyl, wherein the position of the substituted atom is preceded by a number. However, the historical name pyridyl is encouraged by the IUPAC and used instead of the systematic name. [129] The cationic derivative formed by the addition of an electrophile to the nitrogen atom is called ...