Synthesis of meso-substituted dihydro-1,3-oxazinoporphyrins

• Satyasheel Sharma and
• Mahendra Nath

Beilstein J. Org. Chem. 2013, 9, 496–502, doi:10.3762/bjoc.9.53

• -oxazine ring system were successfully synthesized from 5-(4-aminophenyl)-10,15,20-triphenylporphyrin in good yields. The structures of the target products were established on the basis of spectral data and elemental analyses. Keywords: dihydro-1,3-oxazinoporphyrins; iminoporphyrins; La(OTf)3; Mannich

• -triphenylporphyrin using SnCl2 under acidic conditions [41][42]. Firstly, meso-(4-aminophenyl)porphyrin 1 was reacted with salicylaldehyde or 5-chlorosalicylaldehyde in the presence of La(OTf)3 as a Lewis acid catalyst in toluene under reflux to afford the corresponding iminoporphyrins 2 and 3, which on reduction by

• NMR, IR, mass and UV–vis data. The 1H NMR spectra of all the free-base porphyrins showed a singlet around δ −2.7 ppm corresponding to the internal NH protons. Iminoporphyrins 2 and 3 showed the OH and N=CH protons as singlets around 13.4 and 8.9 ppm, respectively. For the aminoporphyrins 4 and 5, the