N-4-phenyl picolinamide {JBE0105}

N-4-phenyl picolinamide JBE0105

2012/09/08

Planning:

This is the 1-armed version of the ligands we’ve been trying to make. This synthesis is from {Organic Letters, 2011, 13, 9, 2256-2259, Kaname Sasaki and David Crich*} It looks like a pretty simple reaction between the carboxylic acid precursor (picolinic acid) and an isocyanate (phenylisocyanate) with an amine base.

Reactant Amount Moles Ratio
Picolinic acid 100mg C6H5O2N, 123.111g/mol 8.12mmol 1.5
Phenylisocyanate 0.59mL 1.096g/mL, C7H5NO, 119.12g/mol 5.42mmol 1
N,N-diisopropylethylamine 1.89mL 129.24g/mol, 0.742g/mL 10.84mmol 2
N,N-dimethylformamide (DMF) 40mL 10mL/mmol isocyanate

From the article, dissolve acid and amine in DMF, add isocyanate (single portion) and stir at 25°C for 2 hours. Remove volatiles under vacuum, purify by prep TLC (99:1 mix CHCl3:MeOH), white needles, Tm=72.6-74.0°C. Hopefully by scaling up it will crystallize without prep TLC.

Synthesis:

Reactant Amount Moles Ratio
Picolinic acid 110mg C6H5O2N, 123.111g/mol 0.894mmol 1
Phenylisocyanate 0.65mL 1.096g/mL, C7H5NO, 119.12g/mol 5.98mmol 6.7
N,N-diisopropylethylamine 2.0mL 129.24g/mol, 0.742g/mL 11.5mmol 13
DMF 25mL 10mL/mmol isocyanate

Combined picolinic acid and amine in DMF, stirred to dissolve at room temperature. Added phenylisocyanate as a single addition, slight orange color developed almost immediately. Addition at 8:25, 2012-09-08. Left to stir at RmTemp. RmTemp is always a bit less than 25degC and since the rxn is scaled up, it can react a bit longer. Color faded to pale yellow over a few hours.

2012-09-10 – ERROR – There was a decimal place mix up here. There should be MUCH more picolinic acid. Since the rxn is run at Rm Temp, I’ll try to salvage it by adding more and letting the rxn go a bit longer. Arg. Need 0.998g more picolinic acid.

Synthesis:

Reactant Amount Moles Ratio
Picolinic acid 0.110+1.000= 1.110g C6H5O2N, 123.111g/mol 9.02mmol 1.5
Phenylisocyanate 0.65mL 1.096g/mL, C7H5NO, 119.12g/mol 5.98mmol 1
N,N-diisopropylethylamine 2.0mL 129.24g/mol, 0.742g/mL 11.5mmol 1.9
DMF 25mL 10mL/mmol isocyanate

Additional picolinic acid added 14:30, 2012-09-10.