2'-Hydroxypropiophenone

PreparationObtained by Fries rearrangement of phenyl propionatewith aluminium chloride in refluxing carbon disulfide , then at 130–150° for 2–3 h after solvent elimination (32–35%)with aluminium chloride in chlorobenzene using microwave irradiation for 3 min at 106° (28%) with aluminium chloride in nitrobenzene at 50° for 18 h (16%) or at 20° for 48 h (10%) with aluminium chloride in nitromethane at 20° for 7 days (20%) with aluminium chloride in heptane at 80–90° for 7 h (53%) or in tetrachlo- roethane at 95° for 5 h (43%) with aluminium chloride without solvent at 250° for 5 min or at 180–200° for 15 min (76–78%), at 140–160° (32–35%), at 140°with zirconium chloride in o-dichlorobenzene at 120° for 3 h (83%) with titanium tetrachloride in o-dichlorobenzene at 150° for 1 h (62%) , in nitromethane at 20° for 7 days (13%) or without solvent at 50° for 10 h (30%)with titanium tetrabromide in o-dichlorobenzene at 150° for 1 h (60%) with stannic chloride at 50° for 3 h (25%) with boron trifluoride at 120–135° for 15 min (15%) with zinc chloride at 180–200° for 15 min (10%) with polyphosphoric acid at 100° (13%) Also obtained by Friedel–Crafts acylation of phenol with propionyl chloride in the presence of aluminium chloride (40%), at 120–130° for 1 h (45%) according to the method Also obtained by acylation of phenol with propionic acidin the presence of boron trifluoride at 165° for 1 h (45%) or at 80° for 2 h (8%) in the presence of polyphosphoric acid at 100° for 10 min (by-product) in the presence of zinc chloride at 160° for 1 h Also obtained by isomerization of 4-hydroxypropiophenone with aluminium chloride (1.5 equiv) at 165° for 1 h (40%) or at 180–200° for 15 min (55%) Also obtained by demethylation of 2-propionylanisole with fuming hydrochloric acid (d = 1.19) in a sealed tube at 110° for 6 h Also obtained (by-product) by heating 3-tert-butyl-4-hydroxypropiophenone with aluminium chloride at 170° for 15 min (13%) Also obtained by treatment of 2,3-dimethylchromone with sodium ethoxide in boiling ethanol for 30 h according to the method Also obtained from 2-allylphenol by treatment with perbenzoic acid in ethyl ether, first at 0°, then between 0° and 25° for 24 h (78%) Also obtained by reaction of 2-bromophenyl propionate in a ethyl ether/hexane/THF mixture at low temperature (78 to 95°) with sec-butyllithium to give, after hydrolysis, the titled ketone (metal-promoted Fries rearrangement) (17%) Also obtained by reaction of ethylmagnesium bromidewith 2-hydroxybenzamide in boiling benzene, followed by hydrolysis (30%)with 2-hydroxy-N,N-diethylbenzamide in boiling benzene, followed by hydrolysis (82–84%) Also isolated by heating of 1-(o-hydroxyphenyl)cyclopropyltrimethylam-monium iodide for 1 h at 140° with 1.5 equiv of N,N-diisopropylethylamine (n