The Periodic Table

Alan

05:51

@orthocresol Mind a question? O:)

I had a look at Ben Norris' answer here:

16

A: What's the difference between a nucleophile and a base?

The two are related, in that most nucleophiles are (Lewis) bases and vice versa. Some good nucleophiles are also strong bases, e.g. $\ce{HO-}$. However, a species can be a good nucleophile and a weak base, e.g. $\ce{I-}$; or a species can be a weak nucleophile and a strong base, e.g. $\ce{t-BuO-}...

There's this bit on nucleophiles:

I understand that iodide is a good nucleophile (in water). Would that mean the generic "Nu" used in the reaction (in the image) refers to any nucleophile stronger than iodide?

( Just want to know if I interpreted that right, or if I've overlooked something )

(Ah, since it's a primary alkyl halide, I guess it's SN2)

M.A.R.

10:50

@Loong Because I can read it, and calling it an edition annoys you

Loong

It doesn't annoy me. I just wanted to clarify that this document is just a draft and not an official release.

Loong

11:43

@orthocresol And then we could also fix the names in the Wikipedia article.

I actually do that a lot: Reading a question concerning a compound on Chemistry.SE and then checking the corresponding Wikipedia article, first of all correcting the names

Loong

12:00

So, I have fixed the worst problem with the names in Wikipedia; but that still doesn't answer the question.

Alan

13:20

@Jan - san (and orthocresol), mind giving this a look? :-)

The answer's option c, but I can't for the world figure out how they arrived at it :-(

I managed to get option b though (route number 1) :-D

And I twiddled around with cyclization (route noumber 2), but that didn't really end well...

< Crosses fingers and hopes it ^ isn't a pain to read >

Loong

13:43

@Alan ketones are more reactive than esters

Alan

Ah, I was AFK, sorry!

<Reads>

@Loong Hmm, but isn't the carbonyl carbon of an ester more electrophilic?

The -OR bit contributes ^

Loong

@Alan No. Pi-donors reduce the electrophilicity.

Alan

@Loong Pi-donors?

I can see two lone pairs on the oxygen in -OR though...

But I'm unfamiliar with the "Pi-donor" term :-(

Loong

14:00

The -OR has available lone pairs.

The carbonyl can accept such electrons into its pi system.

Alan

< Thinks about it >

@Loong I'm not quite sure how that works... :-(

^ Does it involve the carbonyl oxygen gaining a unit negative charge?

Loong

like this

replace the -OH with your -OR

and the double bond with your C=O

Alan

Aha! I see! @Loong Thanks! (I'll try applying this to the question, and see what happens) :-)

Loong

For your question it only means that the first step is addition to the ketone.

Alan

@Loong Which would mean option a is correct :O

Loong

14:08

No. You don't make the workup so fast.

First you get the alkoxide.

Alan

< Nods >

And then cyclization?

^ Some sort of internal nucleophilic attack on the other carbonyl carbon?

Loong

Yes the alkoxide is a nucleophile. And there is a suitable electrophile in range.

Alan

:O

Woot! Let me try this out! :-D

I'll ping you when I'm done, thanks a ton! :-D

Holy Cow, it is c! (acid workup after cyclization worked) \o/

< Bows in reverence to @Loong >

O:)

Loong

:-)

Alan

@Jan Thanks, but Loong helped me out with it. (sorry for pinging you)

@Loong You're an organic chemist? :O

Loong

14:15

no

Alan

< Waves at orthocresol >

@Loong Computational (like Martin)? O:)

orthocresol

@Loong I think you mentioned this before somewhere. I see the "no longer recommended" :)

Loong

@Alan No. I am a radiochemist.

Alan

:O

That the same as a nuclear chemist?

Loong

yeah, almost

Alan

14:18

< Does a little jig >

How close have you been to a fission reactor? :O

<- High-school student. Very curious about it O:)

Loong

@orthocresol Your question gets a bit more complicated, basically because silane is not a PIN, but for example tetramethylsilane is.

@Alan To the actual reactor pressure vessel? Maybe five metres.

orthocresol

I was too quick to rule out bis(tms)amine, I guess?

Loong

Yes. I think it's still in.

orthocresol

Ok, I'll rephrase that and get rid of the extra -1- as well.

Alan

(Had to google "reactor pressure vessel" first) Yup, looks like that's what I had in mind. :-)

< Drools in awe >

Was that 5 metres of concrete? (or tungsten carbide?)

Loong

14:24

Depends. In most running PWR units it was just air plus concrete slabs. In the BWR's next door it was mostly water. My current unit is not in operation yet, so it's just open in the air.

Alan

^ Ah, so there wasn't any fuel in it? :D

(Psst, how close have you been to a "loaded" reactor pressure vessel) >:-)

Loong

@Alan No. My current unit doesn't have fuel in the reactor yet.

@Alan Maybe five metres.

Alan

5 metres. Do you guys wear protective gear?

(Helmet aside) :3

Loong

Only against spreading of contamination

Alan

Contaminants? Like dust (or something more nefarious)?

( Hope I'm not bugging you; just curious ) O:)

Loong

14:32

usually activated corrosion products

Alan

Don't know what specific examples that includes, but I think I get the idea. :-)

Loong

The classic example is Co-60.

Alan

Mind another question? (organic again) :3

Loong

You have an orthocresol here. ;-)

Alan

@Loong Where's the Co-60 usually produced/formed? In the fuel?

@Loong Ah yeah, but since you're clearly active now I thought I'd ask you first O:)

I'll ping orthocresol if you're busy O:)

Loong

14:36

@Alan No. From the cobalt content in stainless steel and other metallic construction materials.

Alan

( Pardon the crappy handwriting )

@Loong Ah! And that gets irradiated, yielding Co-60?

^ In trace quantities

Loong

yes

Alan

:-D

Alan

14:50

@orthocresol Got some time to spare? O:)

orthocresol

sorry tad busy trying to apply for graduate study

Alan

Ah :-)

Martin - マーチン

15:18

Happy New Year from Japan!

4

Alan

15:42

Anyone know how an alkoxide would react with an ester?

I can see it attacking the carbonyl carbon, but I'm not sure what transpires afterwards :/

> Carboxylic acid derivatives like esters, anhydrides, and acid halides react well with good nucleophiles like HO- and RO-

Ah, is it similar to adding a Grignard Reagent to an ester?

orthocresol

15:56

@Alan You're at the point where you would be well served by picking up an undergraduate textbook and reading it. The usual recommendation is Clayden.

Alan

I borrowed "Morrison and Boyd" from the library :-(

I'll try to get my hands on Clayden then :3

orthocresol

never read that, so can't say anything about it

Alan

I see. Thanks for the recommendation! :-D

Mithoron

16:46

@Alan M & B is OK

Alan

:D

Also, Hallo! o/

Mithoron

@Alan o/

Alan

:-)

But what would you prefer?

Between Clayden and Boyd

Mithoron

I don't know clayden enough to tell

Alan

< Nods >

I've heard of Clayden only recently, and orthocresol recommended it as well (still haven't been able to give it a look) :-)

Thanks for the vote of confidence ;-)

Mithoron

16:49

no probs

Alan

I take it you're a Chemist too? :D

Mithoron

Well, I know quite a bit about chemistry for sure

Alan

I can tell (from your answers) :3

Mithoron

About some other stuff too :)

Geoff Hutchison

19:43

Happy New Year from Pittsburgh!

4

I've got a few ideas to start off the "molecular design golf" in 2018. :-)

@orthocresol - good luck in applying to grad school. Let me know if you have questions from the admissions side.

orthocresol

20:20

@Loong, if you are up to it, the Wikipedia names for the salts also need to be changed (LiHMDS, NaHMDS, KHMDS). I guess the corresponding PINs would be "lithium 1,1,1-trimethyl-N-(trimethylsilyl)silanaminide"?

etc.

Loong

sigh more work

I wonder why they didn't prefer the multiplicative name.

orthocresol

It would be easier...

Loong

generally they do:

5

A: What is the rationale of the IUPAC name for DDT?

According to the current version of Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book), a structure with two or more identical units that are linked by di- or polyvalent groups can be named in two ways: by ordinary substitutive nomenclature, in which ...

orthocresol

@GeoffHutchison Thanks! I'll ask you if anything pops up. Most of it is actually done, I'm just finalising some of the stuff I've written, mainly the statement of purpose. (Only applying to UK.) P/S I used Avogadro to generate some pretty images for a presentation at my group meeting, which went down fairly well, so thanks for that too!

@Loong I'm sure you already know it, but work on Wikipedia benefits so many people. To a lesser degree, work on SE does that too, which is one factor which motivates me to try and write thorough stuff that is properly referenced etc. I never really got into WP editing though.

Loong

I hope so. I have more than 1000 edits on the English Wikipedia.

orthocresol

20:31

So, are you a organic chemistry genius or a bot?

:)

Loong

A bot.

orthocresol

!!name/CH4

Loong

If you see a preferred IUPAC name on Wikipedia, there is a good chance that it was my deed.

@orthocresol Rover's Dog Shampoo

orthocresol

Haha, I'd forgotten about that one...

Loong

I had to look it up.

orthocresol

20:40

@Loong There's one that I did.

999 more to go

Loong

nice

I still need 19 nomenclature answers for the gold badge.

orthocresol

What're the requirements for a gold tag badge?

Loong

200 answers, 1000 score

orthocresol

That's a lot of nomenclature answers you have.

My closest gold tag badge is org-chem (130/200).

orthocresol

21:58

@TanYongBoon You may be interested in this:

25

Q: Does OP mean “original poster” or “original post”?

In an online forum, OP means "original poster," but can it also mean "original post?" For example, instead of saying To answer the OP's original question... could one instead say To answer the question in the OP... or would this be an improper use of the term?

Loong

Happy New Year from Finland!

3

Loong

22:12

> 4,444 questions with no upvoted or accepted answers

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