Photoinitiators with functional groups. III. Water‐soluble photoinitiators containing carbohydrate residues

Abstract

SYNOPSISA series of new water-soluble photoinitiators (PIS) for UV curing of water-borne systems was synthesized by covalent bonding of carbohydrate residues such as D-glucose, sucrose, maltose, 1-amino-D-sorbitol and D-gluconicacid-&lactone to the commercially available PI 2-hydroxy-1-[ 4-(2-hydroxy-ethoxy)phenyl] -2-methylpropan-1-one (Darocur 2959) ( 1). In addition, new functional derivatives of 1 containing tosyl-or chloride residues as well as primary or secondary amino groups were prepared. Preliminary photocalorimetric tests of the activity demonstrated excellent efficiencies of the PIS in a commercial water-based acrylate formulation exceeding the photoactivity of the reference PI (1) substantially.CCC osS7-624X/95/060929-11 new water-soluble PIS based on a-hydroxy-alkylphen~nes~~'~.'~ containing carbohydrates as nonionic hydrophilic residues. In addition, results of preliminary tests of the photoactivity of the PIS compared to the basic substances are presented. EXPERIMENTALThe solvents were dried and purified by common methods. 1,2 : 5,6-Di-O-isopropyliden-a-glucofuranose ( 8 ) , l3 glucose pentaacetate ( 11 ) , l4 and maltose octaacetate ( 12) l4 were prepared by known procedures. -sulfonic-acid-2-[ 4-( 2-hydroxy-2- 4-Toluene methyl-1-oxopropyl) -phenoxy]ethylester ( 2)A two-phase mixture consisting of a solution of 20 g (96 mmol) 1 in 200 mL CH2C12,12 g NaOH in 30 mL water, and 1.2 g (3.6 mmol) tetrabutyl ammonium hydrogen sulfate (TBAH) as phase transfer catalyst was stirred at 25°C. A solution of 20 g ( 105 mmol) 4-toluene sulfonylchloride in 50 mL CH2C12 was added slowly and the reaction mixture was stirred for 16 h. The phases were separated and the 929

Photoinitiators with functional groups. V. New water‐soluble photoinitiators containing carbohydrate residues and copolymerizable derivatives thereof

“…Because of the enhanced reactivity of the amino group, glucamine (1‐amino‐1‐deoxy‐ D ‐glucitol) can be used as a versatile hydrophilic synthetic component enabling selective reactions. Therefore, the hydroxyalkylphenone‐based PI 3 with a glucamine residue had already been prepared in our laboratories and was found to offer excellent solubility and good reactivity in water‐based formulations 12. Therefore, it was also of interest to apply this hydrophilic residue to Type II PIs based on benzophenone.…”

“…Because of the extraordinary chemical reactivity of the anomeric hydroxy group of reducing sugars, monosubstituted products can be obtained by glycosidation reactions. Glucose‐modified Type I PI 4 had already been synthesized in our laboratories 12. (Scheme ).…”

“…The following substances were prepared according to the literature: 4 ,12 2,3,4,6‐tetra‐ O ‐acetyl‐α‐ D ‐glucopyranosylbromide,14 2,3,6,′2′,3′,4′,6′‐hepta‐ O ‐acetyl‐α‐ D ‐cellobiosylbromide,14 3 ,12 thioxanthone‐1‐carboxylic acid ( 7 ),15 and 4‐benzyolphthalic anhydride ( 10 ) 16, 17…”

“…In our laboratories, various hydroxyalkylphenones with quaternary ammonium groups11 or carbohydrate residues12, 13 such as 1‐deoxy‐1‐{2‐ [4‐(2‐hydroxy‐2‐methyl‐1‐oxopropyl)‐phenoxy]‐ethyl}‐amino‐ D ‐glucitol ( 3 ) and 1‐{4‐[2‐( D ‐glucopyranosyloxy)ethoxy]phenyl}‐2‐hydroxy‐2‐methyl‐propan‐1‐one ( 4 ) were synthesized. Their photoactivity was tested in commercially available water‐based acrylate formulations.…”

Synthesis and Evaluation of a Novel Co-Initiator for Dentin Adhesives: Polymerization Kinetics and Leachables Study

“…The degradation products which contain organic amine compounds may cause tissue sensitivity and/or other problems related to biocompatibility [2]. Nie and colleagues synthesized and characterized a series of polymerizable amine-coinitiators with the goal of reducing the toxicity [5, 11, 16–19]. …”