Preparation and Characterization of Bridged Naphthoxazinium Salts

Abstract

By condensation of bridged 4‐arylazo‐substituted 3‐hydroxyanilines 18 and bridged or unbridged 4‐arylazo‐substituted 1‐naphthylamines 19–23 with bridged 1‐naphthylamines 15–17 and 3‐aminophenols 14, respectively, in the presence of perchloric acid, bridged naphthoxazinium perchlorates 24–30 have been prepared. The spectral properties of the products have been compared with those of the bridged phenoxazinium salt 31 as well as with data for some unbridged analogues.

Discovery of Novel Benzo[a]phenoxazine SSJ-183 as a Drug Candidate for Malaria

“…[16][17][18][19][20] As a typical example, the synthesis of 5 is shown in Scheme 1. Namely, the nitrate salt of 6 (X = NO 3 )…”

Synthesis and Photophysics of New Benzophenoxazine Derivatives Fused with Julolidine

“…Hence, they are used as potential candidates for dyeing paper, fiber stuff and laser dyes. 3 Moreover, they are useful as photosensitizers in photodynamic therapy, fluorophor in energy and electron-transfer reactions antitubercolastatic or anticancerogenic agents. 4 In the previous reports by our research group we have synthesised several NB derivatives, [5][6][7][8][9][10] and in the present communication we are interested to explore the properties of a rigid structure in comparison with the unrestricted dye.…”

Synthesis of Near-IR Fluorescent Oxazine Dyes with Esterase-Labile Sulfonate Esters

“…Current synthetic approaches to such dyes require a phenolic intermediate such as 29 (Scheme 5). 7,10a,13,14a While the synthesis of the TFMB-protected sulfonate ester 29 was facile, we were unable to isolate the corresponding AcOTFMB-protected phenolic intermediate (Scheme 5). Because the corresponding TFMB-protected phenol 29 is stable, we surmise that the phenol promotes intramolecular deacetylation and self-immolation of the AcOTFMB group (Scheme 5).…”

“…12 This product was then N-methylated and sulfonated to afford 3 . 7a Diazonium coupling yielded 4 , and subsequent acid-catalyzed condensation of this arylazo compound with a m -aminophenol 13 yielded the sulfonated dye 22 , which exhibits maximal absorption at 673 nm and emission at 689 nm in phosphate-buffered saline (PBS).…”

“…7,10a,13,14a First, during the N-alkylation step, protection of the phenol avoids any undesired O-alkylation (Scheme 6), which improves yields and simplifies purification. Second, there is no need to deprotect prior to dye synthesis, eliminating a synthetic step.…”