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Pyrimidines
Pyrimidine (; ) is an aromatic, heterocyclic, organic compound similar to pyridine (). 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. The other diazines are pyrazine (nitrogen atoms at the 1 and 4 positions) and pyridazine (nitrogen atoms at the 1 and 2 positions). In nucleic acids, three types of nucleobases are pyrimidine derivatives: cytosine (C), thymine (T), and uracil (U). Occurrence and history The pyrimidine ring system has wide occurrence in nature as substituted and ring fused compounds and derivatives, including the nucleotides cytosine, thymine and uracil, thiamine (vitamin B1) and alloxan. It is also found in many synthetic compounds such as barbiturates and the HIV drug, zidovudine. Although pyrimidine derivatives such as alloxan were known in the early 19th century, a laboratory synthesis of a pyrimidine was not carried out until 1879, when Grimaux reported the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleotides
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common nutrients by the liver. Nucleotides are composed of three subunit molecules: a nucleobase, a five-carbon sugar (ribose or deoxyribose), and a phosphate group consisting of one to three phosphates. The four nucleobases in DNA are guanine, adenine, cytosine and thymine; in RNA, uracil is used in place of thymine. Nucleotides also play a central role in metabolism at a fundamental, cellular level. They provide chemical energy—in the form of the nucleoside triphosphates, adenosine triphosphate (ATP), guanosine triphosphate (GTP), cytidine triphosphate (CTP) and uridine triphosphate (UTP)—throughout the cell for the many cellular fun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alloxan
Alloxan, sometimes referred to as ''alloxan hydrate'', is the name of the organic compound with the formula OC(N(H)CO)2C(OH)2. It is classified as a derivative of pyrimidine. The anhydrous derivative OC(N(H)CO)2CO is also known, as well as a dimeric derivative. These are some of the earliest known organic compounds. They exhibit a variety of biological activities. History and literature The compound was discovered by Justus von Liebig and Friedrich Wöhler. It is one of the oldest named organic compounds. It was originally prepared in 1818 by Luigi Valentino Brugnatelli (1761-1818) and was named in 1838 by Wöhler and Liebig. The name "Alloxan" emerged from an amalgamation of the words "allantoin" and "Oxalsäure" (oxalic acid). The alloxan model of diabetes was first described in rabbits by Dunn, Sheehan and McLetchie in 1943. The name is derived from allantoin, a product of uric acid excreted by the fetus into the allantois, and oxaluric acid derived from oxalic acid and u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleobases
Nucleobases, also known as ''nitrogenous bases'' or often simply ''bases'', are nitrogen-containing biological compounds that form nucleosides, which, in turn, are components of nucleotides, with all of these monomers constituting the basic building blocks of nucleic acids. The ability of nucleobases to form base pairs and to stack one upon another leads directly to long-chain helical structures such as ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). Five nucleobases—adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U)—are called ''primary'' or ''canonical''. They function as the fundamental units of the genetic code, with the bases A, G, C, and T being found in DNA while A, G, C, and U are found in RNA. Thymine and uracil are distinguished by merely the presence or absence of a methyl group on the fifth carbon (C5) of these heterocyclic six-membered rings. In addition, some viruses have aminoadenine (Z) instead of adenine. It differs in having an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barbituric Acid
Barbituric acid or malonylurea or 6-hydroxyuracil is an organic compound based on a pyrimidine heterocyclic skeleton. It is an odorless powder soluble in water. Barbituric acid is the parent compound of barbiturate drugs, although barbituric acid itself is not pharmacologically active. The compound was first synthesised by Adolf von Baeyer. Naming It remains unclear why Baeyer chose to name the compound that he discovered "barbituric acid". In his textbook ''Organic Chemistry'', the American organic chemist Louis Frederick Fieser (1899–1977) initially speculated that the name stemmed from the German word ''Schlüsselbart'' (literally, the beard (''Bart Latin: ''barba'') of a key (''Schlüssel'')' that is, the bit of a key), because Baeyer had regarded barbituric acid as central (or "key") to understanding uric acid and its derivatives. However, Fieser subsequently decided that Baeyer had named the compound after a young lady whom he had met and who was called "Barbara"' hence t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uracil
Uracil () (symbol U or Ura) is one of the four nucleobases in the nucleic acid RNA. The others are adenine (A), cytosine (C), and guanine (G). In RNA, uracil binds to adenine via two hydrogen bonds. In DNA, the uracil nucleobase is replaced by thymine (T). Uracil is a demethylated form of thymine. Uracil is a common and naturally occurring pyrimidine derivative. The name "uracil" was coined in 1885 by the German chemist Robert Behrend, who was attempting to synthesize derivatives of uric acid. Originally discovered in 1900 by Alberto Ascoli, it was isolated by hydrolysis of yeast nuclein; it was also found in bovine thymus and spleen, herring sperm, and wheat germ. It is a planar, unsaturated compound that has the ability to absorb light. Based on 12C/13C isotopic ratios of organic compounds found in the Murchison meteorite, it is believed that uracil, xanthine, and related molecules can also be formed extraterrestrially. Data from the Cassini mission, orbiting in the Saturn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of The Chemical Society
The ''Journal of the Chemical Society'' was a scientific journal established by the Chemical Society in 1849 as the ''Quarterly Journal of the Chemical Society''. The first editor was Edmund Ronalds. The journal underwent several renamings, splits, and mergers throughout its history. In 1980, the Chemical Society merged with several other organizations into the Royal Society of Chemistry. The journal's continuity is found in ''Chemical Communications'', ''Dalton Transactions'', ''Faraday Transactions'', and ''Perkin Transactions'', all of which are published by the Royal Society of Chemistry. History ;'' Proceedings of the Chemical Society'' * ''Memoirs of the Chemical Society of London'' (1841) * ''Proceedings of the Chemical Society of London'' (1842–1843) * ''Memoirs and Proceedings of the Chemical Society'' (1843–1848) * ''Proceedings of the Chemical Society, London'' (1885–1914) * Published as a supplement to ''Journal of the Chemical Society'' from 1914 to 1956 * ''Proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siegmund Gabriel
Siegmund Gabriel (7 November 1851 – 22 March 1924) was a German chemist. Scientific career Siegmund Gabriel began studying chemistry at the University of Berlin in 1871. He continued his studies at the University of Heidelberg in 1872 with Professor Robert Wilhelm Bunsen. In 1874, he received his doctorate and then returned to Berlin. He began teaching as an assistant, initially in the inorganic chemistry department, before becoming an associate professor in 1886. Gabriel later turned to organic chemistry in his own research. One of Gabriel’s most significant contributions to organic chemistry was made in 1887, when he discovered the Gabriel Synthesis with his partner James Dornbush. The Gabriel Synthesis is a reaction which synthesizes pure primary amines, involving the reaction of potassium phthalimide with an alkyl halide, followed by hydrolysis. The Gabriel Synthesis was adapted by Gabriel in 1889 to a procedure for the preparation of amino acids. In 1891 Gabriel s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amidine
Amidines are organic compounds with the functional group RC(NR)NR2, where the R groups can be the same or different. They are the imine derivatives of amides (RC(O)NR2). The simplest amidine is formamidine, HC(=NH)NH2. Examples of amidines include: * DBU * diminazene * benzamidine * Pentamidine * Paranyline Preparation A common route to primary amidines is the Pinner reaction. Reaction of the nitrile with alcohol in the presence of acid gives an iminoether. Treatment of the resulting compound with ammonia then completes the conversion to the amidine. Instead of using a Bronsted acid, Lewis acids such as aluminium trichloride promote the direct amination of nitriles. They are also generated by amination of an imidoyl chloride. They are also prepared by the addition of organolithium reagents to diimines, followed by protonation or alkylation. Dimethylformamide acetal reacts with primary amines to give amidines: :Me2NC(H)(OMe)2 + RNH2 → Me2NC=NHR + 2 MeOH Properties and appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethyl Acetoacetate
The organic compound ethyl acetoacetate (EAA) is the ethyl ester of acetoacetic acid. It is a colorless liquid. It is widely used as a chemical intermediate in the production of a wide variety of compounds. It is used as a flavoring for food. Preparation Ethyl acetoacetate is produced industrially by treatment of diketene with ethanol. The preparation of ethyl acetoacetate is a classic laboratory procedure. It is prepared via the Claisen condensation of ethyl acetate. Two moles of ethyl acetate condense to form one mole each of ethyl acetoacetate and ethanol. : Reactivity Acidity Ethyl acetoacetate is diprotic: :CH3C(O)CH2CO2Et + NaH → CH3C(O)CH(Na)CO2Et + H2 :CH3C(O)CH(Na)CO2Et + BuLi → LiCH2C(O)CH(Na)CO2Et + BuH Keto-enol tautomerism Ethyl acetoacetate is subject to keto-enol tautomerism. In the neat liquid at 33 °C, the enol consists of 15% of the total. Multicarbon building block Ethyl acetoacetic acid is a building block in organic synthesis since the protons alp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemische Berichte
''Chemische Berichte'' (usually abbreviated as ''Ber.'' or ''Chem. Ber.'') was a German-language scientific journal of all disciplines of chemistry founded in 1868. It was one of the oldest scientific journals in chemistry, until it merged with ''Recueil des Travaux Chimiques des Pays-Bas'' to form ''Chemische Berichte/Recueil'' in 1997. ''Chemische Berichte/Recueil'' was then merged with other European journals in 1998 to form ''European Journal of Inorganic Chemistry''. History Founded in 1868 as ''Berichte der Deutschen Chemischen Gesellschaft'' (, CODEN BDCGAS), it operated under this title until 1928 (Vol. 61). The journal was then split into: * ''Berichte der Deutschen Chemischen Gesellschaft, A: Vereins-Nachrichten'' (, CODEN BDCAAS), and * ''Berichte der Deutschen Chemischen Gesellschaft, B: Abhandlungen'' (, CODEN BDCBAD). Vol. 78 and 79 (1945–1946) were omitted and not published due to World War II. The journal was renamed ''Chemische Berichte'' (, CODEN CHBEAM) in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adolf Pinner
Adolf Pinner (August 31, 1842 – May 21, 1909) was a German chemist. Early life and education He was educated at the Jewish Theological Seminary of Breslau, Jewish Theological Seminary at Breslau and at the University of Berlin (Phd in Chemistry (Doctor der Chemie), 1867). In 1871 he became privat-docent at the University of Berlin. In 1873 he became assistant professor of chemistry at the University of Berlin, and in 1874 professor of chemistry at the veterinary college of that city. In 1884 he was appointed a member of the German patent office, and in the following year, of the technical division of the Prussian Department of Commerce. He has received the title "''Geheimer Regierungsrat''". Literary works Pinner contributed many essays to the professional scientific journal, journals, among which may be mentioned: * "''Darstellung und Untersuchung des Butylchlorals''," in "''Annalen der Chemie''", clxxix., and in "''Berichte der Deutschen Chemischen Gesellschaft''", 1870â ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorus Oxychloride
Phosphoryl chloride (commonly called phosphorus oxychloride) is a colourless liquid with the formula . It hydrolyses in moist air releasing phosphoric acid and fumes of hydrogen chloride. It is manufactured industrially on a large scale from phosphorus trichloride and oxygen or phosphorus pentoxide. It is mainly used to make phosphate esters such as tricresyl phosphate. Structure Like phosphate, is tetrahedral in shape. It features three P−Cl bonds and one strong P=O double bond, with an estimated bond dissociation energy of 533.5 kJ/mol. On the basis of bond length and electronegativity, the Schomaker-Stevenson rule suggests that the double bond form is dominant, in contrast with the case of . The P=O bond involves the donation of the lone pair electrons on oxygen ''p''-orbitals to the antibonding combinations associated with phosphorus-chlorine bonds, thus constituting ''π'' bonding. Phosphoryl chloride exists as neutral molecules in the solid, liquid and gas s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
