Base-Induced Chemiluminescent Decomposition of Bicyclic Dioxetanes Bearing a (Benzothiazol-2-yl)-3-hydroxyphenyl Group: A Radiationless Pathway Leading to Marked Decline of Chemiluminescence Efficiency

• Published in: Journal of organic chemistry 2012-05, Vol.77 (10), p.4725-4731
• Main Authors: Tanimura, Masatoshi, Watanabe, Nobuko, Ijuin, Hisako K, Matsumoto, Masakatsu
• Format: Article
• Language: English
• Subjects: Chemiluminescence; Chemistry; Exact sciences and technology; General and physical chemistry; Heterocyclic compounds; Heterocyclic compounds with n hetero atom and also o and/or s, se, te hetero atoms; Heterocyclic compounds with o, s, se, te hetero atom and condensed derivatives; Organic chemistry; Preparations and properties
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo300417e

Charge-transfer-induced decomposition (CTID) of bicyclic dioxetanes 1b–d bearing a 3-hydroxylphenyl moiety substituted with a benzothiazol-2-yl group at the 2-, 6-, or 5-position was investigated, and their chemiluminescence properties were compared to each other, based on those for a 4-benzothiazolyl analogue 1a. Dioxetanes 1c and 1d underwent CTID to give the corresponding oxido anions of keto esters 8c or 8d in the singlet excited state with high efficiencies similarly to the case of 1a. On the other hand, 1b showed chemiluminescence with quite low efficiency, though it gave exclusively keto ester 2b. The marked decline of chemiluminescence efficiency for 1b was attributed to 1b mainly being decomposed to 8b through a radiationless pathway, in which intramolecular nucleophilic attack of nitrogen in the benzothiazolyl group to dioxetane O–O took place to give cyclic intermediate cis-11.