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Questions tagged [organic-chemistry]

Use this tag for questions relating to organic molecules and their properties (structure of organic molecules, spectroscopic properties, reaction mechanisms, stereochemistry etc). DO NOT use this tag as the only tag in your question, as this tag by itself cannot appropriately classify your question. Always use this tag in addition to other more specific tags.

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The Chemistry behind creating Polylactic Acid (PLA)

I've seen a few videos of persons creating plastics from starch by adding an acid, glycerol, and water, however no explanation of the chemistry. Does anyone know what $\ce{(C6H10O5)_{n} + C3H8O3 + ...
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2answers
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Chemical compounds responsible for the colors in flowers?

I know that anthocyanins are a class of compounds responsible for the purple colors found in flower petals. Anthocyanins (also anthocyans; from Greek: ἀνθός (anthos) = flower + κυανός (kyanos) = ...
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2answers
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Explain the nomenclature of 7-amino-4-methylcoumarin

Can someone explain the nomenclature of 7-amino-4-methylcoumarin, pictured below (from the Sigma-Aldrich website)? The alpha-carbons of the methyl- and amino-groups here are separated by a minimum of ...
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3answers
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Why do Magnesium and Lithium form *covalent* organometallic compounds?

Lithium and magnesium are Group 1 and Group 2 elements respectively. Elements of these groups are highly ionic, and I've never heard of them forming significantly covalent inorganic compounds. Yet ...
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2answers
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By what reaction does (–)-sparteine decompose in ambient conditions?

In its pure form (–)-sparteine is an only-slightly-yellow clear, viscous liquid. Yet, after only a week of being kept in dry, normal atmosphere (in a round bottom flask covered by a septa), some of it ...
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1answer
3k views

Is soap the natural form of Sodium Lauryl Sulfate?

I was told that "Sodium Tallowate, sodium cocoate and sodium palm kernelate are the 'natural' forms of SLS". Is this true? I thought "natural" SLS would be SLS derived from a natural product such as ...
14
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1answer
5k views

How are $\sigma$ and $\sigma^\pm$ determined in Hammett plots?

The Hammett plot is commonly invoked in organic chemistry to reason about the plausibility (or implausibility) of various reaction mechanisms. The vertical axis is essentially the logarithm of an ...
8
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1answer
918 views

What is the difference between an angular and linear skeletal formula?

When drawing a skeletal formula, what is the difference between an angular version and a linear version? I was asked to draw the Z isomer of Resveratrol: For which I drew: However the markscheme ...
12
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1answer
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Why is the benzyne triple bond distorted?

In many places I've seen the "extra" bond in benzyne being labelled as $\ce{sp^2-sp^2}$ overlap or distorted (not parallel) $\ce{p\pi-p\pi}$ overlap. But I've failed to see why we can't have a normal, ...
21
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1answer
3k views

Why do thiols have such a propensity for bonding with mercury?

Historically, thiols $\ce{-SH}$ were known as "mercapto-" due to their strong propensity to bond with mercury. Certain drugs still carry this designation, though mercaptopurine has an $\ce{=S}$ group ...
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2answers
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What are the major factors that influence LogP

The partition coefficient is a very useful metric in characterizing compounds particularly drugs. What chemical properties influence that partitioning? Are chemical moieties additive in their LogP? ...
16
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1answer
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Why does the sulfone ring in tazobactam open when the lactam is hydrolyzed?

One of the drugs I work with is a beta-lactam (4-membered ring with an amide bond) fused to a sulfone ring, tazobactam. It's relatively stable in water; the lactam is not significantly hydrolyzed ...
25
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2answers
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What makes diazo compounds so unstable and explosive?

I once had an Orgo TA refer to a diazo compound as "diazo-boom-boom" (the technical term). I have always been curious as to the reason behind the instability and reactivity. According to Wikipedia ...
12
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3answers
6k views

How can we synthesize para-nitrophenol

During nitration of phenol, both para- and ortho-nitrophenols will be formed. Is there any way in which we can synthesize para-nitrophenol only?
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2answers
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Why is benzyne an intermediate?

I've always seen benzyne (benzene with a triple bond) classified as an "intermediate". I really don't see why it needs to be an intermediate, though. The possible reasons I can come up with are flimsy:...
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3answers
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What makes an epoxide stable?

Overall ring strain seems to be a big issue when it comes to organic chemistry. That is why cyclopentane may be in an "envelope form" or why cyclobutane may be in a kinked, kite form. Both of these ...
9
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1answer
250 views

Why is it that the bigger the side-chain is, its hydrogen atoms tend to be more equatorial?

The most stable cyclohexane form is the chair conformation but on the other hand, the bigger the side-chain of the cyclohexane is, its hydrogen atoms become more equatorial rather than axial, which ...
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2answers
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How do you separate enantiomers?

There are some stereochemical reactions that result in the presence of enantiomers. When moving forward with a practical organic synthesis, how does one usually separate them in order to continue with ...
20
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3answers
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Why are arenes with conjoined benzene rings drawn as they are?

Whilst we are taught to represent benzene as below (A) due to its delocalised electrons, however when two benzene rings share carbons (e.g. naphtalene) it seems to be more commonly represented in ...
18
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2answers
1k views

How large is the energy difference between keto- and enol-form of guanine and uracil?

The nucleobases in DNA and RNA are generally present in the keto-form, and not in the enol-form. As an interesting historical note, James Watson and Francis Crick did initially believe them to adopt ...
19
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4answers
2k views

During the development of aspartame, why was the methyl ester chosen?

One frequent argument against the safety of the synthetic sweetener aspartame is that it can be hydrolyzed, with one of the hydrolysis products being methanol, which is known to be toxic. Of course, ...
40
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1answer
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Mechanism of arene side chain oxidation by permanganate

When treated with hot, concentrated acidic $\ce{KMnO4}$, arenes are oxidised to the corresponding carboxylic acids. For example, toluene is oxidised to benzoic acid. I've tried to examine how this ...
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2answers
1k views

What can I do if I don't get a phase separation between my organic and water phases?

Solvent extraction in a separation funnel is a very common method in preparative organic chemistry. But sometimes you don't get a nice phase separation between the organic and the water phase. What ...
14
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1answer
377 views

How does the choice of metal (oxide) catalyst affect the range of unsaturated compounds that can be hydrogenated?

In the hydrogenation of unsaturated compounds with hydrogen gas and a catalyst, the choice of palladium on carbon is able to hydrogenate alkenes and alkynes, but is unable to hydrogenate aromatic ...
15
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1answer
3k views

Acid catalysed synthesis of ethyl ethoxymethylenemalonate

One synthesis of quinolones begins with the formation of an ethyl ethoxymethylenemalonate, as seen in this Organic Syntheses paper. I've been asked if the malonate derivative would be formed if ...
23
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2answers
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Michael reaction or nucleophilic attack at the alpha carbon of an alpha-beta-unsaturated ketone?

What conditions promote a nucleophile to undergo the Michael reaction over the nucleophilic attack at the alpha carbon of the carbonyl group in an alpha-beta-unsaturated ketone? I'm looking for an ...
15
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2answers
373 views

Can recent developments improve the total synthesis of B-12?

The total synthesis of vitamin B-12 by Robert Burns Woodward and Albert Eschenmoser, is over 30 years old. At its time, it was considered a landmark in the field. With current developments (e.g. ...
18
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1answer
428 views

Precedence of 1,2 carbocation rearrangement

How can one choose which group has more shifting tendency in 1,2 carbocation rearrangement? The obvious order is via the stability of the carbocation of the group. But, phenylic groups have high ...
28
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4answers
6k views

Is activated carbon classified as organic or inorganic?

Organic compounds are typically defined as “molecules containing carbon”. Wikipedia states that there for some historical (read: non-logical) reasons, a few types of carbon-containing compounds ...
15
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1answer
1k views

Stability of organophosphorous vs organophosphates?

In environmental chemistry, most of the organophosphorous compounds we worry about are actually organophosphate compounds. Is there something about the $\ce{C-P}$ bond that makes it less stable (and ...
43
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3answers
9k views

Why does nitration of N,N-dimethylaniline occur at the meta position?

The nitration of N,N-dimethylaniline with $\ce{H2SO4}$ and $\ce{HNO3}$ gives mainly the meta product, even though $\ce{-NMe2}$ is an ortho,para-directing group. Why is this so?
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1answer
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How does Polytetrafluoroethylene (Teflon) differ from Polyvinylidene fluoride (PVDF) as a protein binding membrane material?

PTFE and PVDF (durapore) are both used in protein binding filter membranes (Millipore specifically). Chemically speaking the two polymers differ quite significantly due to the additional fluorides and ...