Dimethyl acetylenedicarboxylate → Dimethyl 3-(4-benzyloxyphenyl)-5-(tert-butyldimethylsilanyloxymethyl)-4-ethylpyrrolo[2,1,5-cd]indolizine-1,2-dicarboxylate

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Reaction Steps

2-(4-Benzyloxyphenyl)-8-(tert-butyldimethylsilanyloxymethyl)-1-ethylindolizine, prepared in example 81, step 5, was reacted with dimethyl acetylene dicarboxylate by the general synthetic principle outlined in example 23, step 6, to afford dimethyl 3-(4-benzyloxyphenyl)-5-(tert-butyldimethylsilanyloxymethyl)-4-ethylpyrrolo[2,1,5-cd]indolizine-1,2-dicarboxylate, which was hydrolysed and desilylated by the general synthetic principle outlined in example 23, step 7, to afford 3-(4-benzyloxyphenyl)-4-ethyl-5-hydroxymethylpyrrolo[2,1,5-cd]indolizine-1,2-dicarboxylic acid as yellow crystals in 70% yield. 1H--NMR (DMSO-d6, 200 MHz) δ: 1.32 (t, 3 H); 3.09 (q, 2 H); 5.18 (s, 2 H); 5.19 (s, 2 H); 7.19 (d, 2 H); 7.31-7.58 (m, 7 H); 8.08 (d, 1 H); 8.40 (d, 1 H).

Provenance & Evidence