A mass spectral investigation of water and acetic acid elimination from 1‐ and 2‐indan derivatives

Water and acetic acid eliminations from 1‐ and 2‐indan derivatives have been investigated. Deuterium labeling, high resolution peak matching and the metastable peak analysis capabilities of a high resolution triple analyzer (E B E) mass spectrometer were employed to examine the eliminations. These experiments showed that water was lost from 1‐indanol via 1,2 and 1,3 processes. These results contrast with those obtained for 1‐tetralol, which specifically eliminates water in a 1,4 process involving the benzylic hydrogens. Water elimination from 2‐indanol is preceded by a slow hydroxyl‐benzylic hydrogen exchange and proceeds specifically 1,2. Water losses from both 1‐ and 2‐indanol are characterized by large kinetic energy releases. Acetic acid elimination is shown to occur specifically 1,3 from 1‐acetoxyindan and 1,2 from 2‐acetoxyindan.