Another lab accident .

Here is the detail:
I put about 30 g NaH in mineral oil in a 1000ml rbf. 500 ml of DMF added at rt.
Then ethyl acrylate 50 ml added at once. The temperature remained the same. No bubbling at all.
Then I went to the balance to weight something.
After about 15 min, the mixture became very hot. At the same time, a lot of gas was released. The reaction is so violent that it didn't stop until almost half of the orange colored mixture was pushed out of the rbf. What a big fountain!

Luckily nothing got hurt.
What happened?
the gas released during the accident was H2(trapped in a balloon which went upward showing the gas has lower density than air).
The smell of acrylate disappeared.

My conclusion is anionic polymerization.
The real question is
Did NaH deprotonate the a-proton of acrylate and initiated the reacion?

puting on THP protecting group.

tetrahydropyrane is stable to basic conditions. easily removed under acidic conditions.

To protect an indole ( N-H):

dihydropyrane + camphor sulfornic acid in DCM. rt.
8hr.

Curtius rearrangement

converts acid to carboxylic azides (use DPPA or acid chloride then NaN3) then upon heating rearrange to an isocyanate.

Then the isocyanate can be trapped by alcohol to form a carbamate.

related rxn: Hofmann Rearrangement, Schmidt Reaction.

Condition I used (to amine):

toluene, dppa, tea, 80C 2h,

then water added, 80C, overnight.

turned out the above transformation is not high yielding.
seems trapping the isocyanate by water is not a good idea.

generally, t-BuOH or BnOH was used to make a carbamate. then remove the carbamate by acid or hydrogenation.

2nd condition I used to make amine:
1. toluene, oxalyl chloride 60C. then concentrated invacuo.
2. acid chloride made in step 1 was dissolved in acetone, then added into NaN3 in water at zero degree. then rt. excess water was used to precipitate the product.
3. heated in toluene to 80C for 2 hr.
4. BnOH added. heated for another 2 hr.
isolate product by column.
5. MeOH, acoh, water + pd/c + H2. rt.
2 hr, then celite filtration.
K2CO3 solution was used to neutralize acoh and make free amine( pH>9). then extract the amine to DCM. the crude product is very clean. no column needed.

FIsher indole synthesis

Condition I used:
40% aquous H2SO4 + toluene
80 C, 4 hr.
phenylhydrazine + 2-methyl-1,3-cyclohexanedione.

2nd generation condition:
1. phenylhydrazine + ketone in EtOH at rt. orange colored hydrazone will be formed in 15 min.
2. remove EtOH invacuo, then add 10%H2SO4 aqueous solution. Turned blue immidiately. heated to reflux for 2-4 hr will decolorize the blue solution. Then simply collect the product by filtration after cooling down.

Oxidation of aldehyde to acid or ester

1. Jones reagent
acidic condition, strong oxidant.

2. I2/MeOH/KOH
forms methylester. mild condition, alkene is untouched.
can't make t-buylester by this way.
tert-aldehyde is more reactive than sec-aldehyde.

3. KMnO4/PH buffer/t-BuOH/water
mild condition, benzyl ether untouched.

4. NaClO2, t-BuOH, PH buffer
mild condition, works for very hindered aldehydes.
t-amlyne used to prevent alkenes from oxidation.

Intermolecular Enolate Heterocoupling

ASAP J. Am. Chem. Soc., ASAP Article, 10.1021/ja804159y
Web Release Date: August 5, 2008
Michael P. DeMartino, Ke Chen, and Phil S. Baran

The direct, convergent synthesis of unsymmetrical 2,3-disubstituted-1,4-dicarbonyl compounds from two carbonyl subunits has proven extremely difficult, several methods for the synthesis of hypothetical succinate 1 are depicted in Figure 2.9,
Efficient, enantioselective syntheses of such entities have escaped synthetic grasp, in spite of their presence in countless natural products and innumerable medicinal remedies. All of the methods depicted suffer from one or more of the following limitations: multistep sequences, installation of requisite disposable functionality on one or both of the monomers, and stereoselectivity problems with prefunctionalization methods and/or during the union of the two monomers. No stereoselectivity was observed or necessary for the most efficient of these methods, the Stetter reaction, as the product was subjected to a pyrrole synthesis. This report is a full account of a research program initiated originally to eliminate the first two of these issues and having since evolved to address the third. By taking advantage of an underutilized and underappreciated reactivity of carbonyl enolates, the oxidative heterocoupling of two enolates joins two different sp3-hybridized carbon centers in a single step without requiring prefunctionalization of the corresponding monomers.

indicator of basicity

Triphenylmethane

The pKa of the hydrogen on the central carbon is around 31. The trityl anion absorbs strongly in the visible region, making it red. This colour can be used as an indicator when maintaining anhydrous conditions with calcium hydride; the hydride reagent reacts with water to form solid calcium hydroxide, while it is also a strong enough base to generate the trityl anion. If the hydride is used up then the solution will turn colourless. The sodium salt can be prepared also from the chloride.

Before the popularization of butyllithium and related strong bases, trityl sodium was often used as a strong, non-nucleophilic base.in the lab, in small scale reaction, triphenylmethane can be used to indicate excess n-Buli or LDA.