A-Acetyl-7-butyrolactone

Acetylanthracene, 30,1 Acetylation, of 2- -acetylphenylhydro-quinone, 34, 1 of hydrogen sulfide, 31, 105 a-Acetyl-7-butyrolactone, 31, 74 Acetyl chloride, 30, 1 (X-ACETYL-5-CHLORO-7-VALEROLACTONE, 31, 1... 

A. 5-Chloro-2-pentanone. A mixture of 450 ml. of concentrated hydrochloric acid, 525 ml. of water, and 384 g. (3 moles) of a-acetyl-7-butyrolactone (Note 1) and a boiling chip are placed in a 2-1. distilling flask fitted with a 90-cm. bulb-type condenser and a receiver immersed in an ice water bath (Note 2). Carbon dioxide is evolved immediately. Heating of the reaction mixture is begun at once, and the temperature is raised at such a rate that the reaction mixture does not foam into the condenser. In about 10 minutes the color changes from yellow to orange to black, the effervescence begins to subside, and distillation commences. The distillation is continued as rapidly as possible... 

Corresponding runs beginning with 128 g. (1 mole) of a-acetyl-7-butyrolactone gave 107-112 g. (89-93%) of crude 5-chloro-2-pentanone. The checkers consistently obtained yields of 79-81% using U. S. Industrial Chemicals, Inc., lactone. 

Chelate systems can also occur in certain cases. Rasmussen and Brattain [6] have observed this in a-acetyl-7-butyrolactone, which has the j3-keto ester structure. The non-enolised form gives rise to bands at 1773 cm (five-membered ring lactone) and 1718 cm (ketone), but there is also a band at 1656 cm , which the authors attribute to a chelated carbonyl group similar to those observed in open-chain products. Halogen substitution in the a-position also raises the carbonyl frequencies. In the extreme case, perflouro-butyrolactone absorbs at 1873 cm due to the influence of the fluorine atoms [29], 2-bromobutyrolactone [12] absorbs at 1797 cm . Anomalous frequencies also occur when electronegative substituents are present on the carbon atom of 7-lactones. Brugel et al. [60] have cited a number of such cases, of which 7-acetoxy-7-valerolactone which absorbs at 1797 cm is a typical example... 

N-Acetylamino-L-tryptophane, 530 17a-Acetyl-A -androstene-3/5,l 7 S-diol, 660 9-Acetylanthracene, 27, 131 a-Acetyl-T-butyrolactone, 676 Acetyl chloride, 11, 263-264, 275, 336 2-, 4-, and 5-Acetylchrysene, 676-677 S-Acetylcoenzyme A, 1157... 

Condensation of 3-(2-amino-4-thiazolyl)comnarin 91 with a-acetyl-y-butyrolactone in a mixture of polyphosphoric acid and POCI3 afforded thiazolo[3,2-a]pyrimidin-5-one 92, while condensation of 91 with P-keto esters gave 7-methyl-3 -(2-oxo-2H-chromen-3 -yl)-5 H-[ 1,3]thiazolo [3,2 -a]pyrimidin-5 -ones 93(Scheme 42). Reaction between 91 and diethyl 2-(methoxymethylene)malonate imder solvent-free conditions yielded 3-(2-oxo-2H-chromen-3-yl)-5-oxo-5H[l,3]thiazolo[3,2-a]pyrimidine-6-carboxylate 94 [67],... 

However, the p-toluenesulfonates of a number of simple monohydric alcohols may be distilled20 182 without decomposition, at a pressure of 0.1 mm. Hg. Similarly, 3,3-dimethyl-3-deoxy-2-0-tosyl-D( )- fycero-tetrono-1,4-lactone ( d( — )-a-hydroxy-/3,/3-dimethyl-7-butyrolactone p-toluenesulfonate ) distils183 at 205°/0.5 mm., and methyl 3,4-di-0-acetyl-2-0-methyl-6-0-tosyl-a-D-altroside may be distilled184 at 10 mm. Hence, this method may sometimes prove useful in separation and purification. Certainly, sublimation under high vacuum186 should prove applicable in many instances. 

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