Anisic anhydride

The K-R reaction has also been useful for structural confirmation of natural products such as tambulin (71), a flavonoid isolated from the seeds of Xanthoxylum acanthopodium In the critical reaction (O-ethoxyphloroacetophenone (72) was allowed to react with anisic anhydride (38b) in the presence of sodium anisate (73) at 170 C to deliver flavone 74 in 65% yield. Flavone 74 was then converted after multiple steps to diethyl ether 75 which corresponded to the diethyl ether of tambulin (71). 

Typical procedure. o-Anisic anhydride [1042] A solution of o-anisic add (500 mg, 1.8 mmol) and distilled triethylamine (0.25 mL, 1.8 mmol) in ethyl acetate (35 mL) was stirred in an ice bath. Triphosgene (90 mg, 0.3 mmol) was then added in one portion, whereupon the immediate predpitation of EtsN HCl was observed. The reaction mixture was kept in the ice bath for 10 min, and then stirred for a further 15 min at room temperature. The solid (EtsN-HCl) was filtered off and washed with ethyl acetate (10 mL). The combined filtrate and washings were concentrated to dryness, and the residue obtained was recrystallized from ethyl acetate and hexane at room temperature to give the title compound as dear crystals (330 mg, 65%). 

Also obtained by reaction of p-anisic anhydride with p-xylene [1631]. 

Derivation Reaction of anisic alcohol with acetic anhydride. 

Turpentine, which is the sap of coniferous trees, contains in addition to terpenes a non-volatile compound of unknown structure, called abietic anhydride. When the sap is distilled with steam, there are obtained oil of turpentine and abietic acid, C19H28O2, which is non-volatile when the distillation is made without steam the residue is called rosin or colophony. Pinene is the fraction of oil of turpentine which boils at 156° it has the specific gravity 0.86 at 25°. Pinene is present in the oils of rosemary, lemon, sage, juniper, thyme, and anise, and in other essential oils. The structural formulas assigned to pinene is as follows —... 

Acetic anhydride Acrolein Aluminum chloride anhydrous 2-Aminopentane p-Anisic acid p-Anisic acid Bis (chloromethyl) ether Cetethyidimonium bromide Cetrimonium bromide Cetylpyridinium bromide Cobalt chloride (ous) Cyclohexane Cyclopentane Diacetone alcohol Dimethyl sulfate... 

Phenylthioglycolic acid C8H8O3 Allyl 2-furoate o-Anisic acid p-Anisic acid Mandelic acid Methylparaben Methyl salicylate Phenoxyacetic acid Resorcinol acetate Tetrahydrophthalic anhydride Vanillin C8H8O3 K... 

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