Four novel crowned spirobenzopyrans containing different substituent at 6-position (5a-5d) were prepared by the condensation of monoazabenzo-15-C-5(4) with the spirobenzopyrans (3a-3d), which were obtained by aldol-type reaction of the Fischer's base(2) with salicylicaldehyde (1a-1d). Their photochromic, cation induced photochromic properties and substituent effect have been investigated. The results show that crowned ether can stabilize the open-forms of spirobenzopyrans, and that alkali-metal cations can induce the isomerization of crowned spirobenzopyrans. The electron with drawing groups at 6-position can increase the stability of open-forms of spirobenzopyrans, but the electron donating groups reduce their stability. In addition, the substituent effect in indoline ring is in opposition to that in benzopyran ring as to stabilizing open-form of indolinospirobenzopyran.

Key words: CROWN ETHER, PYRANE P, SPIRO COMPOUNDS, PHOTOCHROMISM, SUBSTITUENT EFFECT, INDUCTION