Reaction of EtMgBr and estrone, estradiol or ethynylestradiol with paraformaldehyde in hexamethylphosphoric triamide led to regiospecific formylation giving a series of 2-formylestrogens. The structures of the products were elucidated by 13C NMR and MS determination The effect imposed by the formyl and the hydroxyl groups adjacent to one another on the dc of the carbon atoms of carbonyl, ring A and some others was discussed. Possible fragmentation pathway and the relevant regularity of fragmentation were also accounted for.

Key words: MASS SPECTROGRAPHY, C13 NMR SPECTROMETRY, STEROIDS, ESTRADIOL, ESTRONE, GRIGNARD REAGENT, FORMYLATION, POLYOXYMETHYLENE