Pyrimidine structural formulas

Chemical Name 2-Amlno-4-[2-(1 -methyl-5-nltroimldazol-2-yl)vinyl] pyrimidine Common Name Nitromidine Structural Formula ... 

Chemical Name 5-Methvl-7-dlethylamino-1 -triazolo-(1,5-a I-pyrimidine Common Name Trapymin Structural Formula ... 

Azacitidine (5-aza-cytidine, Fig. 8) is a pyrimidine nucleoside analog of cytidine. The structural formula is... 

In any given paper, there is usually a clue, in the form of a structural formula or a chemical property, etc., which fixes the numbering system. Occasionally there is no clue, and an ambiguity is presented. This is particularly troublesome for pyrimidine derivatives, because the carbons of the reactive double bond are numbered differently in the two systems (C5 is the same in both). 

The spin-coupled method has now been applied to a large number of aromatic systems benzene and naphthalene azobenzenes, such as pyridine, pyridazine, pyrimidine and pyrazine five-membered rings, such as furan, pyrrole, thiophen, and thiazole and inorganic heterocycles, such as borazine ( inorganic benzene ) and boroxine, for which we find little evidence of aromaticity. Structural formulae are collected in Fig. 1. For all of these molecules we have included the effects of electron correlation for the Jt electrons but not for the a framework. This a-n separation is an approximation whose utility rests upon the chemistry of aromatic systems — to abandon it would be to ignore this entire body of experience. Furthermore, very extensive calculations [4] have demonstrated that rc-electron only correlation affords an excellent description of ground and excited states of benzene. 

Chemical Name 2,4-Diamino-5-(4-amino-3,5-dimethoxybenzyl)pyrimidine Common Name Aditeren Structural Formula ... 

Chemical Name 2-[4-(1,3-Benzodioxol-5-ylmethyl)-1 -piperazinyl) pyrimidine Common Name -Structural Formula . o-... 

Therapeutic Function Xanthine oxidase inhibitor gout therapy Chemical Name 1 H-pyrazolo[3,4-d] pyrimidin-4-ol Common Name -Structural Formula ... 

The three pyrimidine bases are uracil, thymine, and cytosine, usually abbreviated U, T, and C. Adenine (A) and guanine (G) are the two purine bases. Adenine, guanine, and cytosine are found in both DNA and RNA, but uracil is ordinarily found only in RNA, and thymine only in DNA. Structural formulas of the five bases are given in I Figure 11.3. 

Benzylpyrimidine sulfonamides are based on the combination of a sulfonamide with trimethoprim or tetroxoprim. Chemically, trimethoprim is a 2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidine and has the following structural formula. 

Classify caffeine and theobromine according to whether each is a pyrimidine or a purine. One of these cannot isomerize to an enolic form two different enols are possible for the other. Explain and write structural formulas for the possible enols. 

Structural formulas of the five most important purine and pyrimidine bases found in DNA and RNA.The hydrogen atom shown in color is lost in the formation of an W-glycoside. 

The monosaccharide component of DNA is 2-deoxy-D-ribose (the 2-deoxy refers to the absence of a hydroxyl group at the 2 position), whereas that of RNA is D-ribose. The glycosidic bond is between C-1 (the anomeric carbon) of ribose or 2-deoxyribose and N-1 of a pyrimidine base or N-9 of a purine base. Figure 20.2 shows the structural formula for uridine, a nucleoside derived from ribose and uracil. 

The barbiturates, which include several important drugs used as sedatives (tranquilizers) and hypnotics (sleep-producers), are closely related to the pyrimidines. The structural formulas of barbituric acid and two of its derivatives are given below in these formulas the distribution of the hydrogen atoms between oxygen and nitrogen is uncertain, and... 

Nucleosides consist of (1) a purine or pyrimidine, which is responsible for the high characteristic ultraviolet absorption (2) a pentose, which is either ribose or desoxyribose. The structural formulas of adenosine (I), guanosine (II), uridine (III), and cytidine (IV) are given below. 

The structural formulas of the monomeric constituents of nucleic acids are given in Figure 10.11. These are pyrimidine or purine nitrogen-containing bases, two sugars, and phosphate. DNA molecules are made up of the nitrogen-containing bases... 

The structural formula of thiamine has two heterocyclic rings, which are not condensed one pyrimidine and one thiazol ring. They are connected at the quaternary nitrogen of the thiazol ring thiamine, therefore, always carries a charge. The coenzyme is the pyrophosphate of thiamine. Aside from the pyridine nucleotides, thiamine pyrophosphate was one of the first recognized coenzymes. In conformity with our definition, however, it must be considered a prosthetic group, since it remains tied to the enzyme protein. 

The pyrimidine ring is virtually flat. Its corrected bond lengths, as determined by a least-squares analysis of the crystal structure data for a unit cell of four molecules, are shown in formula (2) (60AX80), and the bond angles derived from these data show good agreement with those (3) derived by other means (63JCS5893) for comparison, each bond... 

Abstract This presentation is a brief review on the resnlts of our work on iodine interaction with thioamides, selenoamides and amides. The thioamides, benzothia-zole-2-thione (BZT) (1), 6-n-propyl-2-thiouracil (PTU) (2), 5-chloro-2-mercap-tobenzothiazole (CMBZT) (3), N-methyl-benzothiazole-2-thione (NMBZT) (4), benzimidazole-2-thione (BZIM) (5), thiazolidine-2-thione (TZD) (6), 2-mercapto-pyridine (PYSH) (7), 2-mercapto-nicotinic acid (MNA) (8), 2-mercapto-benzoic acid (MBA) (9) and 2-mercapto-pyrimidine (PMT) (10) react with producing three type of complexes of formulae [(HL)IJ(l2) (HL= thioamide and n= 0, 1), [(HL) [I3 ] and [(HL-L)]+[l3 ]. The interaction of seleno-amides, derived from, 6-n-propyl-2-thiouracil (RSelJ) (R= Me- (11), Et- (12), n-Pr- (13) and i-Pr- (14)) with I, have also been studied and produced the complexes [(RSeU)IJ of spoke structure. These complexes are stable in non-polar solvents, but they decompose in polar solvents, producing dimeric diselenide compounds or undertake deselenation. 

Since a knowledge of the correct tautomeric form of the pyrimidines is a requisite for understanding the mode of binding to active sites, as well as nucleic acid structure and modification, the formulae of the conventionally-named 2- and 4-hydroxypyrimidines are presented in the correct lactam, or pyrimidone, form in this chapter. Other physical properties of the pyrimidines, such as dissociation constants, protonation sites, and distribution coefficients, are presented in cases where there is a known relation to drug activity. Biogenesis and enzyme control mechanisms are discussed where they relate to an understanding of inhibitor action. 

The heteroaromatic betaines, [l,3,4]thiadiazolo[3,2-a]pyrimidine-5,7-diones (753), which are isoconjugate with methylated xanthines, are in the same way as the latter found to be inhibitors of cyclic AMP phosphodiesterase (78JPS1762). The N-/3-D-ribofuranosyl nucleoside (754) inhibits the synthesis of RNA and DNA but not of protein. The primary blockade is in the synthesis of purine nucleotides (79MI42902). RNA synthesis is also inhibited by [l,3,4]thiadiazolo[3,2-a]pyrimidines of structure (755). The activity is attributed to the chemical reactivity at C-2 leading to reactions with an SH or OH group in RNA polymerase (80ABC1923). Compounds with the 7-oxo formula (756) are claimed to be useful as immune enhancers (78GEP2712932). 

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