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1st February 2012 @ 00:35
****Experiment concluded on 06/02/12. Conclusion pending. [b][u]Hazard and Risk Assessment[/b][/u] [data]2725[/data] [b][u]Previous Related Experiments[/b][/u] [blog]3915[/blog] [blog]2801[/blog] [blog]2796[/blog] [b][u]Following Experiments[/b][/u] [b][u]Procedure[/b][/u] [b]01/02/12[/b] A mixture of paraformaldehyde (2.29 g, 76.2 mmol), cyclohexanecarboxylic acid (9.77 g, 76.2 mmol), 2,2-diethoxyethylamine (10.15 g, 76.2 mmol) in methanol (76 mL) was cooled in a brine ice bath. KAB4-2 (~10 g, 76 mmol) was added dropwise to the mixture at 0 °C, turning the white solution yellow. The reaction mixture was allowed to warm to room temperature and stirred from 14:00. [data]2731[/data] [b]03/02/12[/b] At 12:00 (+46 hours) The reaction mixture was concentrated under reduced pressure and the dark brown liquid residue was dissolved in ether (150 mL) then washed with water (100 mL) and brine (100 mL). The organic layer was dried over magnesium sulfate before the solvent was removed [i]in vacuo[/i] to give crude KAB5-2 as a dark yellow-brown oil (31 g). [data]2747[/data][data]2749[/data][data]2751[/data][data]2755[/data] TLC of the crude product in EtOAc/hexane, 3:1, v/v showed two spots. One corresponding to the expected product and a polar baseline spot. The crude product was dissolved in EtOAc (25 mL) then passed through a short silica gel column eluting with neat EtOAc. The yellow filtrate was concentrated under reduced pressure to give KAB5-2 as a dark yellow oil . [data]2753[/data][data]2757[/data] [b]06/02/12[/b] The KAB5-2 final product was dried under a high vacuum before analysis by H-NMR. Yield: 28.0 g, 91%. [data]2785[/data][data]2787[/data] [b][u]References[/b][/u] [1] H. Cao, H. Liu, A. Doemling,[i] Chemistry-a European Journal[/i][b] 2010[/b], 16, 12296 (DOI: 10.1002/chem.201002046) -------------------------------------------------------------- NOTES 01/02/12 - Reaction mixture started turning a pale orange colour during the addition of KAB4-2. --------------------------------------------------------------
Attached Files
Scheme KAB5-2 & KAB6-2
HRA KAB5-2 & KAB62
Table KAB5-2
Reaction mixture at 1 hr
Reaction mixture at 46 hours
Concentrated reaction mixture
Dilution with ether
After washing with water. Aqueous fraction on left.
Column of crude KAB5-2
Left: combined aqueous fractions; Right: organic fraction
Removing solvent to give pure KAB5-2
Drying under high vacuum
Final KAB5-2