Compounds derived from acyloxy-and aryloxyacetic acids
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C10H10O4
mol.wt. 194.19
Syntheses
OH
-Preparation by hydrolysis of o-acetoxy-α-acetoxyacetophenone (SM) with aqueous potassium hydroxide solution by gently warming for 10-15 min on a water bath maintained at 80° (71%). SM was obtained by cupric chloride-catalyzed decomposition of o-acetoxy-α-diazoacetophenone in dioxane solution in the presence of acetic acid (65%, m.p. 161-162°) [879]. -Also obtained by oxidative rearrangement of 2-acetoxy-α-bromoacetophenone in moist DMSO for 28 h at 20° (49%) [416]. -Also obtained by reaction of potassium acetate with o-hydroxy-α-bromoacetophenone in acetone at r.t. for 90 min [1114]. COCH 2 OCOCH3
m.p. 170-171° [879], 58-59° [416], 57° [1114]. One of the reported melting points is obviously wrong. Ogle and Main [1114] consider that the reported product of m.p. 171° [879], identified by only elemental and IR analysis, is not the titled product. 1H NMR [416] [1114], 13C NMR [1114], IR [879] [1114]. 2-(Acetyloxy)-1-(4-hydroxyphenyl)ethanone [20816-46-0]
C10H10O4
mol.wt. 194.19
Syntheses
OH
-Preparation by reaction of α-chloro-4-acetoxyacetophenone with potassium acetate in boiling ethanol for 4 h (quantitative yield) [1099]. -Preparation by reaction of acetic acid and potassium acetate COCH2OCOCH3 with α-chloro-4-hydroxyacetophenone in refluxing ethanol for 1 h (80%) [1238]. -Preparation by reaction of acetic acid with p-hydroxyphenacyl chloride in acetonitrile in the presence of triethylamine, first in an ice bath for 15 min, then at reflux for 3 h (50%) [1577]. -Also refer to: [917] [918]. m.p. 133° [1238] [1577], 127° [1099]. 2-(Acetyloxy)-1-(2,4-dihydroxyphenyl)ethanone [63124-23-2]
C10H10O5 Synthesis
OH COCH2OCOCH3
-Preparation by reaction of acetoxyacetonitrile with resorcinol (Hoesch reaction) (85%) [287], (40%) [1474].
HO m.p. 167-168° [1474], 164°5 [287]; NMR [1474], IR [1474], UV [1574].
1H
mol.wt. 210.19
180
HYDROXYACETOPHENONES
2-(Acetyloxy)-1-(3,4-dihydroxyphenyl)ethanone [67083-58-3]
C10H10O5
mol.wt. 210.19
Synthesis
OH OH
COCH2OCOCH3
-Preparation by adding a solution of sodium acetate in aqueous acetic acid to an ethanolic solution of 3,4-dihydroxy-α-chloroacetophenone, and heating at reflux for 24 h (83%) [336]. Isolation from natural sources
-Obtained by mild acid hydrolysis of sclerotized cuticles from locusts (Schistocerca gregaria) and beetles (Pachynoda sinuata) [45]. m.p. 157-160° [336]; UV [45], MS [45] [1242]; column chromatography [45]; TLC [45]. 2-(Acetyloxy)-1-(4-hydroxy-3-methoxyphenyl)ethanone [139473-80-6]
C11H12O5
mol.wt. 224.21
Syntheses
OH
-Obtained by reaction of α-chloroacetovanillone with potassium acetate, *in refluxing ethanol for 2 h (56%) [1198] or for 4 h (67%) [1099]; COCH2OCOCH3 *in refluxing acetic acid and ethanol mixture for 1 h (57%) [909]. -Also obtained by partial hydrolysis of 4,α-diacetoxy-3-methoxyacetophenone (m.p. 75-76°) in the presence of potassium bicarbonate in methanol for 16 h at 20° (96%) [454]. -Also obtained from 4-hydroxy-3-methoxy-α-diazoacetophenone by slowly heating in acetic acid at
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