Anomalous acetoxylation of aromatic nuclei: some structural requirements in the substrate

Abstract

For certain aromatic nuclei, bromination in acetic acid and in the presence of pyridine is accompanied by nuclear acetoxylation. As first observed with galbulin, when two alkoxyl groups, one meta and one para to a benzylic centre of the substrate are present, acetoxylation occurs at the intervening ortho position. Under the given conditions, acetoxylation occurs at position 8 of 6,7-dimethoxy-1-phenyl-1,2,3,4,-tetrahydronaphthalene, and at position 2 of 3,4,-dimethoxy diphenyl- and triphenyl-methanes. Acetoxylation does not occur in the absence of either of the alkoxy groups or in the absence of pyridine, nor does it occur in the pendant ring of 1-(3�,4�-dimethoxypheny1)- 1,2,3,4-tetrahydronaphthalene. These results are consistent with the earlier suggestion that the reaction occurs by way of initial oxidative formation of a doubly benzylic cation.

Synthesis of Rigidified eIF4E/eIF4G Inhibitor-1 (4EGI-1) Mimetic and Their in Vitro Characterization as Inhibitors of Protein–Protein Interaction

“…Thus, 6,7-dimethoxy-4-chromanone ( 43a ) 56−58 afforded ( E / Z )- 46a , while 7,8-dimethoxy-4-chromanone ( 43b ) 59,60 and 6,7-dimethoxy tetralone ( 43c ) obtained from 4-oxo-4-(3,4-dimethoxyphenyl)butanoic acid ( 39 ) 61 yielded ( E / Z )- 46b and ( E / Z )- 46c , respectively, in analogy to Scheme 2 (Scheme 7). …”

“…To examine the effect of a dimethoxy substituent on the ring A replacing a dichloro substituent, we synthesized three dimethoxy substituted rigidified analogues of 1 starting from the respective tetralone and chromanones. Thus, 6,7-dimethoxy-4-chromanone ( 43a ) 56 − 58 afforded ( E / Z )- 46a , while 7,8-dimethoxy-4-chromanone ( 43b ) 59 , 60 and 6,7-dimethoxy tetralone ( 43c ) obtained from 4-oxo-4-(3,4-dimethoxyphenyl)butanoic acid ( 39 ) 61 yielded ( E / Z )- 46b and ( E / Z )- 46c , respectively, in analogy to Scheme 2 (Scheme 7 ).…”

Scandium(III) Triflate-Catalyzed Friedel−Crafts Alkylation Reactions

“…(Dimethoxyphenyl)phenylmethane (3f). This compound was obtained as a ca. 1:1 regioisomeric mixture by the reaction of 2f with 1a : bp 135 °C/0.4 mmHg (Kugelrohr distillation); IR (neat) 700, 1030, 1080, 1140, 1154, 1237, 1262, 2834, 2936, 3027 cm -1 ; 1 H NMR (200 MHz, CDCl 3 ) δ 3.60−4.10 (m, 8H), 6.60−7.40 (m, 8H); 13 C NMR (CDCl 3 ) δ 35.8, 41.4, 55.6, 55.7, 55.8, 60.3, 110−153 (additional several peaks).…”