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12th September 2012 @ 02:06
Mnr: 41-50
The aim over the next few reactions is to compare reaction rate, conversion and yield varying reaction temperature and Yb loading

MNR46-8, 10 mol% Yb at room temperature
MNR46-9, flasks were mixed up therefore ended up being a duplicate of
MNR46-10, stoichiometric Yb at reflux


Hazard Assessment
HIRAC MNR41_47_48.pdf

To a solution of KAB22-1 (1eq) in HPLC grade acetonitrile (0.03 M) under argon at 0 °C , was added was added acetyl chloride (1.8 eqs), lutidine (1.4 eqs) and Yb(OTf)3 (01-1 eqs). The reaction was then stirred at room temperature or at reflux and aliquots taken at noted time intervals for LC analysis.

Sample were taken up to 5 hours then the reaction were left overnight.

Only MNR46-8 showed significant signs of product. Surprisingly, MNR46-10 showed signs of the product degrading over time (assuming the last data point is an outlier)


MNR46-8 was worked up after 48 hours.

The mixture was washed saturated sodium bicarbonate solution (10 mL) and the aqueous layer was extracted with ethyl acetate (3 × 15 mL). The organic fractions were combined, dried over MgSO4, filtered and concentrated under reduced pressure to yield a yellow oil, 0.329 g.

TLC in 50% EtOAC/Hex. Spot left to right, lutidine, KAB22-1, co-spot, worked up MNR46-8, co-spot, product (MNR46-4). Two spots were seen in the SM spot, this can be put down to some hydrolysis in the TLC spotter sample as it was a few weeks old. TLC also show complete consumption of SM to two new spots, them being desired product and hydrolysis products.


Column in 40% EtOAc/Hexane

Frac 1-7 - mainly CHO, not as much amine, volatile?? 0.049 g


Frac 9-18 - product with unknown peak at 2.25. Product appears to come up as two conformers in a ration of 2:1. This is clearer in the 13C. 0.080 g, 0.27 mmol, 34 %




At 10 mol% the reaction IS catalytic, at room temperature the reaction takes about 2 days to go to completion.

The reaction using 1 eq of catalyst appears to have a negative effect of the progress of the reaction or it degrades the product. This needs looked into further.



quenched and worked up as normal but then volume reduced and washed with 10% citric acid.


one wash appeared to get rid of most of the lutidine, crude mass 0.190 g

running the crude down a column yielded product but upon standing the product hydrolysed back to aldehyde and amine. Yields and masses not calculated.


see Re-synthesis of MNR46-13 for a fuller account and explanation.
Linked Posts
Attached Files
mnr46-8 table.PNG