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  • Mono ‐ and Bis ‐Alkylated Lumazine Sensitizers: Synthetic, Molecular Orbital Theory, Nucleophilic Index and Photochemical Studies
Title: Mono ‐ and Bis ‐Alkylated Lumazine Sensitizers: Synthetic, Molecular Orbital Theory, Nucleophilic Index and Photochemical Studies
Abstract Mono‐ andbis‐decylated lumazines have been synthesized and characterized. Namely,mono‐decyl chain [1‐decylpteridine‐2,4(1,3H)‐dione]6aandbis‐decyl chain [1,3‐didecylpteridine‐2,4(1,3H)‐dione]7aconjugates were synthesized by nucleophilic substitution (SN2) reactions of lumazine with 1‐iododecane inN,N‐dimethylformamide (DMF) solvent. Decyl chain coupling occurred at theN1site and then theN3site in a sequential manner, without DMF condensation. Molecular orbital (MO) calculations show ap‐orbital atN1but notN3, which along with a nucleophilicity parameter (N) analysis predict alkylation atN1in lumazine. Only after the alkylation atN1in6a, does ap‐orbital onN3emerge thereby reacting with a second equivalent of 1‐iododecane to reach the dialkylated product7a. Data from NMR (1H,13C, HSQC, HMBC), HPLC, TLC, UV‐vis, fluorescence and density functional theory (DFT) provide evidence for the existence ofmono‐decyl chain6aandbis‐decyl chain7a. These results differ to pterinO‐alkylations (kinetic control), whereN‐alkylation of lumazine is preferred and then to dialkylation (thermodynamic control), with an avoidance of DMF solvent condensation. These findings add to the list of alkylation strategies for increasing sensitizer lipophilicity for use in photodynamic therapy.  more » « less
Award ID(s):
1856765 1956098
PAR ID:
10454317
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
Photochemistry and Photobiology
Volume:
97
Issue:
1
ISSN:
0031-8655
Page Range / eLocation ID:
p. 80-90
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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