Adenine formula

Adenine is a weak base Which one of the three nitrogens designated by arrows in the struc tural formula shown is protonated in acidic solution" A resonance evaluation of the three protonated forms will tell you which one is the most stable... 

Chemical Name 9-/3-D-arabinofuranosyl-9H-purine-6-amine monohydrate Common Name Adenine arablnoside spongoadenosine Structural Formula ... 

Reduced nicotinamide-adenine dinucleotide (NADH) plays a vital role in the reduction of oxygen in the respiratory chain [139]. The biological activity of NADH and oxidized nicotinamideadenine dinucleotide (NAD ) is based on the ability of the nicotinamide group to undergo reversible oxidation-reduction reactions, where a hydride equivalent transfers between a pyridine nucleus in the coenzymes and a substrate (Scheme 29a). The prototype of the reaction is formulated by a simple process where a hydride equivalent transfers from an allylic position to an unsaturated bond (Scheme 29b). No bonds form between the n bonds where electrons delocalize or where the frontier orbitals localize. The simplified formula can be compared with the ene reaction of propene (Scheme 29c), where a bond forms between the n bonds. 

FIGURE 10.1 The structural formula of riboflavin and partial structures of riboflavin compounds. The latter show only those portions of the molecule that differ from riboflavin. 1 — Riboflavin (RF), 2 — flavin mononucleotide or 5 -riboflavin monophosphate (FMN or 5 -FMN), 3 — flavin adenine dinucleotide (FAD). 

Only a few years after the Miller-Urey experiment was published, J. Oro was able to synthesize one of the most important biomolecules, adenine. This purine derivative is not only a component of the nucleic acids, but as ATP, adenosine triphosphate (in combination with ribose and three phosphate residues), it plays a key role in the metabolism of all living creatures. The chemical formula of adenine is C5H5N5, or expressed in another way, (HCN)s. 

Fig. 10.10 Diverse sets of interconverting supramolecular and macromolecular polymers which may be generated by using only two adenine and uracil nucleobases (the gray formulas are stereochemically unstable).

Additive toxic effects, 25 213—214 Adducts, of vinyl chloride, 25 632 Adenine, 8 174. See also ADP entries Adenocard, molecular formula and structure, 5 98t... 

Nicotine adenine dinucleotide phosphate (NADP+), 24 147 Nicotinic acid, 9 477-478 26 291 alkaloid precursor, 2 78 Ni-Cr alloys, 23 499. See also Nickel-chromium entries NiCrAlY coatings, 13 508 nido designation boranes, 4 184-186 boron hydrides, 4 170, 172-176 Nidrel, molecular formula and structure, 5 129t... 

Development of ditopic receptors 58 for both an anion and a cation is a logical extension [19b]. It should be stressed that the recognition by cyclodextrins, calixarenes, hemicarcerands, and many other systems does not involve specific recognition sites, whereas tetrahedral recognition by 53 and 54, the adenine 56 selective binding, and multiple recognition like the one shown in formula 59 [20] require the presence of specific sites in receptor capable of directional interactions. 

Problem 22.47 Write the structural formulas for adenine monophosphate (amp) and triphosphate (atp) nucleotides, (atp is the most important source of energy for biochemical processes in living tissues the energy comes from the breaking of the high-energy polyphosphate bonds.)... 

Figure 4.7 Structural formula of nicotinamide adenine dinucleotide in its reduced form of NADH + H+ and its oxidized form NAD+.

An important aspect of enzymatic oxidation-reduction reactions involves the transfer of hydrogen atoms. This transfer is mediated by coenzymes (substances that act together with enzymes) nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). These two species pick up H atoms to produce NADH and NADPH, respectively, both of which can function as hydrogen atom donors. Another pair of species involved in oxidation-reduction processes by hydrogen atom transfer consists of flavin adenine triphosphate (FAD) and its hydrogenated form FADH2. The structural formulas of NAD and its cationic form, NAD+, are shown in Figure 4.7. 

Figure 1. Structural formulae (/3-form shown) and overall redox reaction of nicotinamide adenine dinucleotide, NAD+, and its reduced form, the enzymatically active 1,4-NADH. Reproduced with permission from ref. 35. Copyright 1991 Elsevier Science Publishers.

Fig. 15.2 a -d. Formulas of some modified bases occurring naturally in transfer RNA s. a Hypo-xanthine, a guanine derivative lacking the 2-amino group b dihydrouracil and c 4-thiouracil, two derivatives of uracil d 1-methyladenine, a positively charged derivative of adenine... 

Purine derivatives are considered to be prebiotic molecules. Purine as well as adenine (HCN) can be formed from hydrogen cyanide in the presence of ammonia in a prebiotic atmosphere. Similar reaction in the presence of water can lead to other purines. Purine chemistry goes back to the roots of organic chemistry. Uric acid was the first purine isolated from bladder stones by Scheelc in 1776. The correct empirical formula of uric acid was established much later by Liebig and Mitscherlich. The correct structure was suggested by L. Medicus and was shown to be correct by the syntheses ofHorbaezewski. Behrend and Roosen, and unambiguously by E. Fischer. The development of purine chemistry by E. Fischer is a milestone in heterocyclic chemistry. 

Fig. 1 Model of the adenine molecule (77/-purin-6-amine), one of the two purine nucleobases forming the nucleotides of the nucleic acids. The molecule has the formula C5H5N5 making it a 70-electron system. Today, systems of this size are amenable to high quality ab initio quantum chemical studies.

As we pointed out, however, the electrons will not flow unless they have someplace to go. In the light phase of photosynthesis, the electrons moving down the electron transport chain are taken up by nicotinamide adenine dinucleotide phosphate, a molecule with nearly as many symbols in its formula as letters in its unwieldy name. Luckily, it suffices to refer to this entity by its initials, NADP+, a practice common in the complicated world of biochemistry. 

However, from a consideration of the formulas of adenine and guanine, the ribosyl group cannot be attached at position (2 ) of the purine because the free amino group of guanine (and guanosine) is attached to... 

In the early attempts to identify the nitrogenous bases of desoxy-ribosenucleic acid, some confusion arose for two reasons. At first, the products obtained by hydrolysis of nucleoprotein were studied, and there was no assurance that any particular base came from the nucleic acid rather than from the protein. Then, when the nucleic acid itself became available, the hydrolytic agents at first employed were sufficiently drastic to cause some deamination of the amino-purines (with the production of some xanthine and hypoxanthine) and some demethylation of thymine to uracil. In 1874, Piccard isolated guanine (and h3T>oxanthine) from sperm nuclein. Kossel and Neumann discovered in the hydrolysate of thymus nucleic acid two new pyrimidine bases which they named thy-mine and cytosine but they assigned incorrect empirical formulas to them. In 1894, they correctly described thymine as CsHgOjNs, but cytosine was not purified and characterized till much later. " " Levene now analyzed a series of nucleic acids from a variety of sources and found " that they all contained guanine and adenine. By mild hydrolysis of thymus nucleic acid, Steudel obtained guanine and adenine as the sole purine bases and demonstrated that they occur in equi-molecular proportions. Levene and Mandel confirmed this result and showed that the two purine bases and the two pyrimidine bases (thymine and cytosine) all occur in thymus nucleic acid in equimolecular proportions. 

T, and phosphoric acid. The base is called adenine and will be represented as RiNH. Adenylic acid has the formula R2N- C5HsO - OPOxH2. 

The antibiotic nucleocidin (28) is produced by Streptomyces calvus (n. sp) that was isolated from a soil sample obtained in Dinepur, India. Dilute-acid hydrolysis of nucleocidin yields adenine and a six-carbon, reducing sugar. Its ultraviolet spectrum indicates that it is a 9-substituted adenine, and its empirical formula is CnHieNeOsS. A partial structure of nucleocidin (28) has been proposed. ... 

---