文章目錄
pyridine: 吡啶
a colorless volatile liquid with an unpleasant odor, present in coal tar and used chiefly as a solvent.
詞源：mid 19th century: from Greek pur ‘fire’ + -ide + -ine.
-ide，在化學中， forming nouns denoting binary compounds of a nonmetallic or more electronegative element or group.
-ine，在化學中，forming names of alkaloids, halogens, amines, amino acid, and other substances.
diazine: 二嗪（二氮(雜)苯）
diazines are a group of organic compounds having the molecular formula C4H4N2. Each contains a benzene ring in which two of the C-H fragments have been replaced by isolobal nitrogen. There are three isomers:
- pyridazine (1,2-diazine)
- pyrimidine (1,3-diazine)
- pyrazine (1,4-diazine)
詞源
- diazine ：di- two + azo nitrogen + ine
- pyridazine：pyrid- + azine
- pyrimidine：late 19th century: from German Pyrimidin, from pyridine, with the insertion of -im- from imide (酰亞胺).
- pyrazine：German Pyrazin blend of Pyridin pyridine az(o)- azo-
pyridazine (噠嗪 nitrogen atoms at the 1 and 2 positions). 
Pyrimidine is an aromatic heterocyclic organic compound similar to pyridine. It has two nitrogen atoms at positions 1 and 3 in the ring.
pyrazine (吡嗪 nitrogen atoms at position 1 and 4 in the ring)
cytosine, thymine, and uracil
In nucleic acids, three types of nucleobases are pyrimidine derivatives: cytosine ©, thymine (T), and uracil (U).
注：nucleobases: 核鹼基
cytosine：胞嘧啶
Cytosine is one of the four main bases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at position 2).
詞源：from cyto- “cell” + -ose + chemical suffix -ine
“The name cytosine (due to Kossel and Neumann) is misleading. Cytosine is not, like adenosine and guanosine, a nucleoside (核苷) but the sugar-free base.”
thymine：胸腺嘧啶
Thymine is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G-C-A-T. The others are adenine, guanine, and cytosine.
詞源：the acid so called because obtained from the thymus gland (warty excrescence)
uracil: 尿嘧啶
(organic chemistry) One of the bases of RNA, pairing with adenine.
詞源：From uro- (urine) + ac(etic) + -ile. Coined in 1885 to denote its association with uric acid.
purine：嘌呤
Any of a class of organic heterocyclic compounds, composed of fused pyrimidine and imidazole rings, that constitute one of the two groups of organic nitrogenous bases (the other being the pyrimidines) and are components of nucleic acids.
詞源：1898, from German purin (Fischer), said to be from Latin purum, neuter of purus “clean, pure” + Modern Latin uricum “uric acid” + chemical suffix -ine.
adenine：腺嘌呤
C5H5N5, found in certain glands and tissues, which pairs with thymine in DNA and uracil in RNA.
詞根：from Greek adēn “gland,” + chemical suffix -ine. So called because it was derived from the pancreas of an ox.
guanine：鳥嘌呤
A substance first obtained from guano; it is a nucleic base and pairs with cytosine in DNA and RNA (by means of three hydrogen bonds).
詞源：Spanish guano (birdshit 鳥糞) + -ine