This document discusses purines, which are organic compounds that are one of the two types of nucleobases found in nucleic acids. Purines consist of fused pyrimidine and imidazole rings and contain four nitrogen atoms. Adenine and guanine are the two purine nucleobases found in DNA and RNA. The document provides details on the structure and properties of purines, their sources in food, their roles in nucleic acids, and the early history and synthesis of purine starting from uric acid.

1. Purine- Basics and Synthesis
Varinder Khepar
PhD Chemistry
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3. Nucleic Acid Building Blocks
• Nucleic acids are polymers that consist of
nucleotide residues. DNA and RNA are
polymers of nucleotide units.
• Each nucleotide is put together from three
building blocks:
1. phosphoric acid
2. a monosaccharide
3. an organic base
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4. 1) Phosphoric Acid
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5. 2. Monosaccharides
• All nucleotides are constructed from one of
these two monosaccharides:
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6. 3) Organic Bases
• There are two types of organic bases (amines)
that are incorporated into nucleic acids:
a) purines
b) pyrimidines
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8. Purines
• Purine is a heterocyclic aromatic organic
compound composed of a pyrimidine ring
fused with imidazole ring.
• It consists of two hydrogen-carbon rings and
four nitrogen atoms
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9. • Purine is both a very weak acid and an even
weaker base
• It is water-soluble
• It comprises adenine and guanine as
nucleobases.
• The melting point of purine is 214 °c
• Catabolism results in the production of uric
acid
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10. Occurrence of purines
• Found in high concentration in meat and meat
products, especially internal organs such
as liver and kidney
• Plant-based diets are low in purines
• Moderate amount of purine is also contained
in fish, seafood, mushrooms, green peas,
dried peas and beans.
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11. Notable purines
• There are many naturally occurring purines. They
include the nucleobases adenine and guanine .
• In DNA, these bases form hydrogen bonds with
their complementary pyrimidines, thymine and c
ytosine, respectively.
• In RNA, the complement of adenine
is uracil instead of thymine.
• Other notable purines
are hypoxanthine (4), xanthine (5) and uric acid.
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13. History of purine
• The word purine (pure urine) was coined by
the German chemist Emil Fischer in 1884.
• He synthesized it for the first time in 1898.
• The starting material for the reaction
sequence was uric acid (8), which had been
isolated from kidney stones.
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14. • Uric acid (8) was reacted with PCl5 to give
2,6,8-trichloropurine (10), which was
converted with HI and PH4I to give 2,6-
diiodopurine (11). The product was reduced to
purine (1) using zinc dust.
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15. Synthesis of purine
• Laboratory synthesis
• Purine is obtained in good yield when formamide is heated
in an open vessel at 170 °C for 28 hours.
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16. Synthesis of Purine derivatives
• Four molecules of HCN tetramerize to
form diaminomaleodinitrile (12)
• Five molecules of HCN condense in an
exothermic reaction to make adenine
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18. Traube purine synthesis (in 1900)
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19. Refrences
• http://www.sivabio.50webs.com/nucleicacid.
htm
• Fasullo, M., & Endres, L. (2015). Nucleotide
Salvage Deficiencies, DNA Damage and
Neurodegeneration. Int. J. Mol. Sci., 16(12),
9431–9449. doi:10.3390/ijms16059431.
• https://byjus.com/biology/difference-
between-purines-and-pyrimidines/
• https://en.wikipedia.org/wiki/Purine
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20. THANK YOU
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