7 Benzoylbutyric acid

Benzoylbutyric acid may also be prepared by this method. Glutaric anhydride (0.68 mole) dissolved in part of the benzene is added to the rest of the benzene in which the aluminum chloride is suspended the temperature is kept below 15° for one and one-half hours, including the time of addition an 80-85 cent yield of 7-beiuzoylbu(yric acid melting at 125-126° is obtained. 

The Hantzsch pyridine synthesis gives initially a dihydropyridine from the cyclization reaction. Adaptation of this reaction to the use of a 2-methylenethiazolidine yields the fused tetrahydro derivative (502) (77LA1888). Perhydro derivatives are simply prepared from 2-substituted thiazolidines by cycloalkylation as for (503) (80S387). The thiazolidine may also be generated in situ as in the reaction between y-benzoylbutyric acid and 2-mercaptoethylamines under azeotropic conditions to yield (504) (65JOC1506). 

The synthesis of a variety of perhydro-imidazo[l,2-fl]pyridin-5-ones is illustrated by the preparation of 212 by treatment of y-benzoylbutyric acid with 1,2-diaminoethane in the presence of /7-toluenesulfonic acid in boiling xylene (69USP3454585). Compounds 213 (70GEP1802468) and 214 (72AKZ438 82EUP65724) were similarly obtained by the reaction between the appropriate ketoester and 1,2-diaminoethane. 

Also, in a very straightforward manner, condensation between 4-benzoylbutyric acid and ethanolamine gives the lactam (229) (69JOC165), and the oxidation of 2-piperidinoethanol (230) with potassium hexacya-noferrate(lll) in aqueous 2M potassium hydroxide solution gives perhydro-oxazolo[3,2-fl]pyridine (232) via the iminium ion (231) [7IJCS(B)I745]. 

The preparation of 8a-phenylperhydrothiazolo[3,2-a]pyridin-5-one (313) by the reaction between y-benzoylbutyric acid and mercaptoethyl-amine illustrates the synthesis of a number of similar compounds (67USP3334091). 

Both the aldehyde and the alcoholic groups are affected in 8-phenyl-8-hydroxyvaleraldehyde, which is oxidized by potassium permanganate to y-benzoylbutyric acid (equation 367) [749]. 

T-Benzoylbutyric acid, 13, 13 Benzoyl chloride, 12, 41, 62 Benzoyl peroxide, 13, 86... 

An ionic liquid of a different type (n-butylpyridinium tetrafluoroborate, [BPy]BF4) has been used as a recyclable solvent for the reaction of 4-benzoylbutyric acids 40 with [hydroxy(2,4-dinitrobenzenesulfonyloxy)iodo]benzene (HDNIB) leading to 5-benzoyldihydro-2(3//)-furanones 41 (Scheme 6.16) [58]. 

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