Lithium Hydroxide → Porphyrin precursor

Participants

Reaction Steps

7H, FIG. 7. 2,5-Bis[(3-acetoxypropyl-5-formyl-4-methylpyrrol-2-yl)methyl]-3,4-diethylpyrrole 7G (5.98 g, 0.011 mol) and LiOH (1.76 g, 0.042 mol) were added to 400 mL of 95% methanol, which had been degassed with nitrogen prior to use, and the mixture heated to reflux under a nitrogen atmosphere. The reaction became homogeneous when heated. After heating for 1.25 hours, the reaction was allowed to cool to room temperature. The product precipitated as a tan color solid as the reaction cooled. The volume of the reaction mixture was reduced to 75 mL on a rotary evaporator and the resulting slurry placed in the freezer for several hours. The product was filtered and then purified by forming a slurry with 400 mL of methanol and 50 mL of water and heating close to boiling. The slurry was first cooled to room temperature, reduced to 1/2 volume under reduced pressure, and placed in the freezer for several hours. The product was collected by filtration and vacuum dried to yield 4.96 g of a tan powder (94%): 1H NMR (CD3OD, 300 MHz): δ0.96 (6H, t, CH2CH3), 1.49 (4H, p, CH2CH2CH2OH), 2.25 (6H, s, pyrrole--CH3), 2.32-2.43 (8H, m, CH2CH3 and CH2CH2CH2OH), 3.46 (4H, t, CH2CH2CH2OH), 3.85 (4H, s, (pyrrole)2 --CH2),9.34 (2H, s, CHO); CI MS (M+) 480; HRMS (M)+, 481.2942 (calc for C28H39N3O4, 481.2941).

Provenance & Evidence