868156-48-3Relevant academic research and scientific papers
Reactivity of substrates with multiple competitive reactive sites toward NBS under neat reaction conditions promoted by visible light
Grjol, Bla?,Jereb, Marjan
, p. 5235 - 5248 (2021/06/07)
Regioselectivity of visible-light-induced transformations of a range of (hetero)aryl alkyl-substituted ketones bearing several competitive reactive sites (α-carbonyl, benzyl and aromatic ring) with N-bromosuccinimide (NBS) was studied under solvent-free reaction conditions (SFRC) and in the absence of inert-gas atmosphere, radical initiators and catalysts. An 8-W energy-saving household lamp was used for irradiation. Heterogeneous reaction conditions were dealt with throughout the study. All substrates were mono- or dibrominated at the α-carbonyl position, and additionally, some benzylic or aromatic bromination was observed in substrates with benzylic carbon atoms or electron-donating methoxy groups, respectively. Surprisingly, ipso-substitution of the acyl group with a bromine atom took place with (4-methoxynaphthyl) alkyl ketones. While the addition of the radical scavenger TEMPO (2,2,6,6-tetramethylpiperidin-1-yloxy) decreased the extent of α- and ring bromination, it completely suppressed the benzylic bromination and α,α-dibromination with NBS under SFRC.
NEW PHOTOINITIATORS
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Page/Page column 38-39, (2010/02/14)
The invention relates to novel photoinitators of formulae (I), (II), (III), (IV), (V) and (VI) wherein R1 and R2 are each independently of the other C1-C8alkyl; C1-C4alkyl substituted by OH, C1-C4alkoxy, -COO(C1-C8alkyl), (C1-C4alkyl)-COO-, -CN, benzyl, phenyl or by -N(R15)(R16); C3-C6alkerlyl, benzyl, -CH2-C6H4-(C1-C4alkyl) or phenyl; or R1 and R2 together are unbrarched or branched C2-C9alkylene or C3-C6-oxa- or -aza-alkylene; R3, R4, R5 and R6 are each independently of the others hydrogen, C1-C8alkyl, C3-C6alkenyl, benzyl, -CH2-C6H4-(C1-C4alkyl) or phenyl; R3 and R4 together and/or R5 and R6 together are unbranched or branched C2-C9alkylene; A is CI, Br, -O-R9, -N(R11)(R12) or -S-R18, A' is -O-, -NH- or -NR11-; A" is CI, Br, -O-R9, -N(R11)(R12) or -S-R18 or hydrogen, X is -O-R10 or -N(R13)(R14), n is an integer from 1 to 10, preferably an integer from 1 to 4, especially 1, 2 or 3; R7 is a linker; R8 is a bivalent C2-C3alkylele radical.
