23

In compound A, the negative and double bonded oxygens bound to the phosphorus are equivalent: $\hspace{5.1cm}$ In compound B, they are not equivalent: $\hspace{7.5cm}$


18

1) Why is only triphenyl phosphine used here. Why not some stronger nucleophile like say trimethyl phosphine? Trialkyl phosphines can particpate in the Wittig reaction just fine, but they create some other problems. Let's say you were going to create the phosphonium salt from ethyl iodide and trimethyl phosphine. It would form in high yield, but in the ...


17

As cibrail said, DNA is a polymer of nucleotides. They join themselves through phosphodiester bonds (a specific kind of covalent bond) that can grow to as much as millions of nucleotides. What part in the strand contributes to the overall non neutral charge? The reason why DNA is negatively charged is the phosphate group that makes up every nucleotide (...


16

To answer the question in the title: Yes, ATP can be synthesised, isolated and you can even eat it. It would be very expensive to do so but considering others put gold on most of their food that’s not a reason in itself not to. While eating too high a dose of ATP is not beneficial as per Paracelsus’ law, small amounts are certainly not harmful. However, ...


15

Let me add to iad22agp's excellent answer. Often times in introductory biochemistry classes, the difference between phosphoanhydride and phosphate ester bonds is not adequately explained. ATP (and ADP) contain phosphoanhydride bonds. In these bonds, two phosphoric acid groups are condensed into one: $\ce{R~-H2PO3 + R'~-H2PO3 -> R-HO2P-O-PO2H-R' + ...


13

Phosphorine (IUPAC: phosphinine) actually has aromatic character nearly as great (88%) as that of benzene. According to the reference, phosphorine is sufficiently stable to be handled without air-free techniques; and it undergoes electrophilic substitution reactions similar to those of benzene.


12

This reaction is the Ohira–Bestmann modification1,2 of the Seyferth–Gilbert homologation.3,4 In the original Seyferth–Gilbert homologation, a diazomethane phosphonate is used to convert carbonyl compounds to alkynes with one extra carbon in the presence of potassium t-butoxide. I used acetophenone as the reactant here just to simplify things, but the same ...


9

I am reluctant to post this as an answer because it is not really backed up by much research, but since nobody has said anything yet, here's my theory: It is probably to do with the fact that the covalently bound sarin (which necessarily involves kicking out either $\ce{RO-}$ or $\ce{F-}$) mimics the transition state for acetylcholine hydrolysis too well, ...


8

Expanding upon the comment above detailing how exogenous ATP isn't that great of an idea given the path of delivery, it's also important to note that our body focuses more on consumption, storage, and mobilization of fuels. The actual ATP production and utilization happens on a cell by cell basis, but fuels are moved around the entire body extracellularly.


7

Think of ADP and ATP as substituted phosphoric anhydrides. ATP has a strong tendency to hydrolyze due to the electrophilic nature of the central phosphorus atom which bears two electron-deficient phosphate leaving groups. (note that ADP has only one, and is a poorer source of energy, whereas AMP has only a normal phosphate ester linkage.) ATP is kinetically ...


7

My inclination is to call this reaction a "phosphono-Claisen condensation." A Claisen condensation is the alpha-acylation of an ester with another ester. In this case, the typical carbon-centered ester is replaced with a phosphonate, so phosphono-Claisen condensation specifies that difference. Avoiding the proper name, "alpha-acylation of a phosphonate" is ...


7

The difference between the two molecules is highlighted in red. The functional group in 3-phosphoglycerate is a carboxylic acid. That in glyceraldehyde-3-phosphate is an aldehyde. Sugars have the general formula $\ce{C_$n$H_{$2n$}O_$n$}$. To accomplish this specific ratio of carbon to hydrogen to oxygen, the requirement is that one of the carbons must have ...


7

I am fairly sure that for both, there are practicality issues at hand. This is almost certainly so for the choice of phosphine. Even though PPh3 is absolutely terrible from an atom economy point of view, and even though PPh3O can be a real pain to remove after the reaction is done, at least it's a nice white solid which doesn't smell. On the other hand, the ...


6

The difference is basically one oxygen atom. If you consider monoethyl phosphate as an example, the ethyl alpha-carbon bears a phosphate group, whereas the ethoxy oxygen bears a phosphoryl group.


5

Seems like the silicon atom is more oxophilic as compared to the phosphorus atom. This could in principal be explained by the higher strength of the $\ce{Si-O}$ bond, as indicated by the dissociation energies $D$ (see http://www.wiredchemist.com/chemistry/data/bond_energies_lengths.html): $$\begin{array}{ccc} \hline \textbf{Bond} & \textbf{Dissociation ...


5

Two separate papers I found containing this paritcular type of reaction had the following wording: Protection of the ketoester as the dioxolan followed by reaction with lithium diethylmethylphosphonate and hydrolysis of the intermediate dioxolanphosphate led to the diketophosphonate.$^{[1]}$ and "... treatment with lithiated ethylphosphonate ...


5

I would point out (as did the author of the question) that sarin hydrolyzes in water in days to weeks without the need of an enzyme, and also that carboxylic acid fluorides (e.g. acetyl fluoride) also rapidly hydrolyze, despite the strength of the C-F bond. The ability of these acyl fluorides to hydrolyze is due to the relative ease of addition of water or ...


5

Your question is a valid analytical chemistry question which has deep roots in history. No, the reason is not that $\ce{P2O5}$ reacts with water to from phosphoric acid and that is why $\ce{P2O5}$ values are quoted as suggested in the comments below the question. This is a very old historical tradition. In older analytical chemistry, chemists had only two ...


4

Yesterday I chanced upon a rather obscure name for it: the "Corey–Kwiatkowski condensation". The reaction between lithium phosphonamide or phosphonate and ester to give β-keto phosphonamide or phosphonate is called the Corey–Kwiatkowski condensation. Wang, Z. Corey-Kwiatkowski Reaction. Comprehensive Organic Name Reactions and Reagents [Online]; ...


4

Great question, but unfortunately without a great answer. Chemistry is very inconsistent in its naming of phosphates. In addition to the terms diphosphate and pyrophosphate, the term bisphosphate is also used. Someone will probably put in an answer that cites "official" IUPAC or IUBMB rules. In many cases (but not all) these rules are more sensical and ...


4

Yes it can. It also has the advantage that the trimethyl phosphine oxide produced is water soluble and thus easier to remove from a reaction mixture than triphenylphosphine oxide which is notoriously difficult to get rid of. I have used it for a Staudinger reduction of an alkyl azide when triphenyl phosphine was unreactive. However, trimethyl phosphine is ...


4

As far as I am aware, the selection of the best ligands for transition-metal catalysed reactions is still trial and error. In fact, not only is the selection of ligand trial and error but so is the choice of starting materials to result in that metal–ligand combination. What the original discoverer of a reaction method typically do is run a number of ...


3

DNA is basically a polymer of nucleotides. These are held together by covalent bonds formed between the phosphate groups, each of which forms and ester with a hydroxyl group of the pentose of the NEXT nucleotide. This uses two of the three acidic 'OH' groups of the acid, leaving the last free to ionize. This ionization leaves a negative charge on each ...


3

The usual substitutive nomenclature for organic compounds was extended to various other elements including phosphorus. The current rules for name construction of organic compounds containing phosphorus are included in Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book). These recommendations cover typical ...


3

Metaphosphoric acids general formula is (HPO3)n ; where n denoted number of phosphoric acid units present in the ring with n being greater or equal to 3. These acids are actually the phosphoric acid units bonded together in rings (cyclic structures), hence forming metaphosphoric acid molecules. In Metaphosphoric acids, each phosphorus has an oxidation state ...


3

Acetylcholinesterase is important enzyme and its mechanism of function is well known. In active site, it has two pockets: anionic pocket (to attract positively charged Quaternary nitrogen of choline) and esteric pocket. The esteric pocket consists of a serine side chain (a $\ce{-CH2-OH}$ function) as depicted in following cartoon, which pacilitate the ...


3

Wittig reactions can be performed with all sorts of phosphanes. The resulting phosphonium salts can be deprotonated by all sorts of bases, as long as the base is basic enough. Triphenylphosphane has the advantage that its phosphonium salt can only be deprotonated on one carbon atom: the three ipso-phenyl carbon atoms are quarternary and thus cannot be ...


3

Both methyl parathion (O,O-Dimethyl O-(4-nitrophenyl) phosphorothioate) and ethyl parathion (O,O-Diethyl O-(4-nitrophenyl) phosphorothioate) are organothiophosphates with identical structure except for dimethoxy group in methyl analog has been replaced by diethoxy group in ethyl analog. Both analogs are acetylcholinesterase (AChE) inhibitors, although ...


2

ATP is an unstable molecule in unbuffered water, in which it hydrolyses to ADP and phosphate. This is because the strength of the bonds between the phosphate groups in ATP is less than the strength of the hydrogen bonds (hydration bonds), between its products (ADP + phosphate), and water acid anhydrides are generally prone to hydrolysis into two acid ...


2

How exactly is energy created by oxidative phosphorylation? Energy is "created" by the syntesis of ATP. The ATP molecule is considered an energy carrier, because it is used in other reactions as a source of energy. The released energy comes from the loss of one or two phosphate gropus to form ADP or AMP. Remember that energy is not created, but simply ...


Only top voted, non community-wiki answers of a minimum length are eligible