Benzoyl acetate

Although phenols have not participated in the Conrad-Limpach reaction under certain conditions thiophenols were not as innocent. Lee and coworkers reported mixtures of thiochromenones and quinolones from reactions of amino-thiophenols with ethyl benzoyl acetate. Amino-thiophenol 67 reacted with ethyl benzoylacetate 68 in PPA to give a mixture of thiochromenone 70 and quinolone 69 in which the quinolone predominated. 

The mercaptals obtained by the acid catalyzed reaction of J3-ketoesters, e.g., ethyl acetoacetate, with methyl thioglycolate (73) undergo the Dieckmann cyclization with alcoholic potassium hydroxide at lower temperatures to give ethyl 3-hydroxy-5-methyl-2-thiophenecarboxylate (74) in 75% yield. ° Besides ethyl acetoacetate, ethyl a-ethylacetoacetate, ethyl benzoyl acetate, and ethyl cyclopentanonecarboxylate were also used in this reaction/ It is claimed that /8-diketones, hydroxy- or alkoxy-methyleneketones, or /8-ketoaldehyde acetals also can be used in this reaction. From acetylacetone and thioglycolic acid, 3,5-dimethyl-2-thiophenecarboxyl-ic acid is obtained. ... 

The condensation of arylsulfonyl acetonitriles 369a-c with 22a proceeds via addition of the in-situ formed anion 370 to the arylsulfonyl acetonitriles 369 to afford the dimers 371, in 69-94% yield, and hexamethyldisiloxane 7 [136]. Furthermore, y9-dicarbonyl compounds such as ethyl acetoacetate 372 a or ethyl benzoyl-acetate 372b are O-silylated by 22 a or 22 c to rather stable alkyl 3-O-trimethylsilyl-oxycrotonoate 373a and alkyl 3-0-trimethylsilyloxy-3-phenyl acrylate 373b [130]. Aliphatic nitro compounds such as nitromethane are O-trimethylsilylated and further transformed into oligomers [132] (cf Section 7.6) and are thus unsuitable reactants for silylation-C-substitutions (Scheme 4.50). 

The protective method has also been employed with 3-ketoesters. In this case, the goal is to avoid keto-enol photoisomerization that is an efficient energy-wasting channel. Scheme 74 shows that direct photorearrangement of aryl benzoyl acetates (298) to the ort/jo-hydroxydibenzoylmethanes (299) is poor, whereas irradiation of the related acetal derivatives gives higher yields [208]. The resulting ort/ o-hydroxydibenzoylmethanes are precursors for the synthesis of flavones. Related flavonoids can be obtained in similar yields by PFR of aryl dihydrocinna-mates [209]. 

Olivetol. (5-Alkyl Resourcinol) BER 69, 1644 (1936). Mix 25 g of ethyl-3,4,5-trimethoxy benzoyl acetate and 2.0 g of clean sodium in 100 ml ethanol and warm to react. Add 2 g n-propyl iodide (this may be replaced with n-amyl iodide) and heat on a steam bath for 12 hours, then neutralize and remove the ethanol by distillation. Extract the residue with ether, dry, and evaporate in vacuo to get 30 g of the alkyl acetate. Heat 22 g of this acetate in 5% KOH ethanolic solution for 1 hour at 50° and let stand to precipitate 14 g of 3,4,5-trimethoxyvalerophenone. Mix 11 g of the above product with 60 g of sodium in 600 ml ethanol. Warm and after dissolving the sodium add 2 liters of water. M e acidic with HCl acid and remove the ethanol by distillation. Extract with ether, dry, and evaporate the ether in vacuo to get if. g olivetol dimethyl ether. To demethylate this ether add it to 70 ml of hydrogen iodide and heat to boiling and reflux for two hours. Distill and keep the fraction at 160°-170° with 3-4 mm of vacuum applied to the distillation set-up. Yield about 6 g. 

Highest yields are obtained when the reaction is carried out in boiling toluene until all water and ethanol are eliminated by azeotropic distillation. Other /S-ketocarboxylic esters such as ethyl benzoyl acetate, o-methoxybenzoyl acetate and ethyl acetonedicarboxylate react similarly with aromatic amidoximes (50). 

By reacting 2-amino-3,4,5,6-tetrahydropyridine (118) with ethyl aceto-acetate or ethyl benzoyl acetate in pyridine, Wamhofif and Lichtenthaler178 obtained 1 4 equilibrium mixtures of the tautomers 119 and 120. 

Benzoic ester with acetic ester yields benzoyl-acetic ester, while with acetophenone it gives dibenzoyl-m ethane ... 

This reaction has been applied to a great number of carbonyl compounds, e.g., cyclopentanone,27 1,3-cyclohexanedione,36 5,5-dimethyl-l,3-cyclohexanedione,S5 1-acenaphthenone,24,25 1,3-indane-dione,35 1,3-phenalanedione,85 86 sodium salts of 3-aryl-3-oxo-propanals,39 2,3-dihydrobenzo[6]thiophen-3-one,40 sodium benzoyl-acetate,41 benzoylacetonitrile,29 30,88 ethyl cyanoacetate,30 35 cyano-acetanilide,30 barbituric acid,35 rhodanine,35 jV-phenylrhodanine,37 and iV-methylenebenzothiazoline.37... 

Amide formation, from a carboxylic acid and urea, 37, 50 from 2 ammo 5 nitroamsole and ethyl benzoylacetate, 37, 4 from aniline and ethyl benzoyl acetate, 37, 3... 

Ethoxyquin, 23 Ethyl Acetoacetate, 72 Ethyl Benzoyl Acetate, 72 Ethyl-(E)-2-butenoate, 72 Ethyl-fraras -2-butenoate, 72 Ethyl Crotonate, 72 Ethylene Brassylate, 72... 

Ethyl Acrylate, 486, 686 Ethyl Alcohol, 136, 849 Ethyl Alcohol, 136 Ethyl o-Aminobenzoate, 486 Ethylp-Anisate, 486, 686 Ethyl Anthranilate, 486, 687 Ethyl Benzoate, 486, 655 Ethyl Benzoyl Acetate, 486, (S3)72 Ethyl-(E)-2-butenoate, 486, (S3)72 Ethyl-fraraj -2-butenoate, 486, (S3)72 Ethyl Butyl Ketone, 502 Ethyl Butyraldehyde, (Sl)72... 

Similarly, the a-methylene group of acetoacetic ester is oximinated by the action of sodium nitrite in glacial acetic acid (63%). Nitrosation of alkylated malonic, acetoacetic, and benzoyl acetic esters with subsequent cleavage affords an excellent synthesis for a-oximino esters, RC(=-NOH)COjC2Hj. A survey of several possible procedures for this conversion has been made." If a /3-keto acid is nitrosated, then the Carboxyl group is lost and an a-oximino ketone is formed, viz.,... 

Anhydro-a-hydroxy-mercuribenzoyl acetic acid, CcHg.CO— CH—CO—0—Hg.—Three grams of benzoyl acetic acid in 50 c.c. of... 

The phenanthroindolizine alkaloids can be visualized as arising by the condensation of two molecules of dihydroxyphenylalanine or one molecule of dihydroxypheny]alanine and one of t3Tosine (or their equivalents, the corresponding benzoyl acetic and phenyl pyruvic acids) with ornithine (or its equivalent, y-aminobutyraldehyde). 

---