Novel Syntheses of bis-Spiropyran Photochromic Compounds Using Ultrasound II

Abstract

bis-Spiropyran photochromic compounds derivatives (3′, 3′-trimethylindoline-2-spiro-2′-benzopyran), were synthesized using ultrasonic energy (25 kHz, 55 Watts). The reaction times were between 10 to 20 min. and higher yields comparing with the conventional reported methods, were obtained.