Exp081-3.JPG

Objective

To investigate the stability of the furan ring of acetamide of 5-methylfurfurylamine in 10% TFA, in order to investigate the behavior of furan containing Ugi products.

Procedure

In a clean NMR tube N-[(5-methyl-2-furyl)methyl]acetamide (1mmol, 153mg), obtained from Exp078 was weighed out, to it CDCl3 (900uL) was added. HNMR and CNMR spectra were obtained. To the NMR tube, then Trifluoroacetic acid (100uL) was added to make it a 10% in CDCl3. The reaction was monitored by HNMR.

Results

HNMR of N-[(5-methyl-2-furyl)methyl]acetamide
CNMR of N-[(5-methyl-2-furyl)methyl]acetamide
81A ( (N-[(5-methyl-2-furyl)methyl]acetamide + TFA )
t = 04min
t = 08min
t = 12min
t = 19min
t = 25min
t = 48min
t = 14h 26min
t = 23h 09min
t = 88h (3.6days)

Discussion

  1. After 88 hours it is evident that TFA does not affect either the furan ring or the methyl group on it, as was observed in a previous experiment with a furan bearing Ugi product in 10% TFA in CDCl3 (EXP067).
  2. The sensitivity to acid seen in previous experiments apparently has to do with groups not present in the above acetamide. It may have to do with the free amine group formed after deprotection.

Conclusion

The acetamide of 5-methylfurfurylamine in 10% TFA in CDCl3 is stable for at least 4 days at room temperature.

Log

2007-03-29

19:15 : Weighed out acetamide in a clean and dry NMR tube, added CDCl3 (900 uL).
19:40: Obtained HNMR and CNMR of the acetamide in CDCl3
20:42 : Added TFA (100 uL) into the NMR tube.
20:46 : Obtained HNMR (t = 04min)
20:50 : Obtained HNMR (t = 08min)
20:54 : Obtained HNMR (t = 12min)
21:01 : Obtained HNMR (t = 19min)
21:07 : Obtained HNMR (t = 25min)
21:30 : Obtained HNMR (t = 48min)

2007-03-30

11:08 : Obtained HNMR (t = 14h 26min)
19:51 : Obtained HNMR (t = 23h 09min)

2007-04-02

12:42 : Obtained HNMR (t = 88h almost 3 and half days)

Tags

Acetamide InChI=1/C8H11NO2/c1-6-3-4-8(11-6)5-9-7(2)10/h3-4H,5H2,1-2H3,(H,9,10)
TFA InChI=1/C2HF3O2/c3-2(4,5)1(6)7/h(H,6,7)