120 THE FORMATION OF CYCLIC KETONES CO 2 H C CH 2 R = CH 3) C 8 H B ,OCH3 R = CH 3l CsH5,OCH 8 xxm xxiv Although there seems to be some question in regard to the influence exerted by an alkyl group thus situated, 16 " a more powerful directing substituent, such as the methoxyl group, appears to have a definite deactivating effect. Thus while 7-phenylbutyric acid (I) was cyclized by hydrogen fluoride (p. 157) to the extent of 92%, 16 the p-methoxy derivative XXIII (R = OCH 3 ) was converted by the same treatment to 7-methoxytetralone-l (XXIV, R = 0CH 3 ) in only 61.5% yield. 17 Similarly /3-phenylpropionic acid (III) was cyclized by hydrogen fluoride in 73% yield, 16 while under the same conditions, ring closure of the p-methoxy derivative LXXXI (p. 157) took place only to the extent of 3%. 18 In addition, the comparison of yields is consistent with the premise that a six-membered ring is formed more readily than a five-membered one. Meta
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This note was uploaded on 11/20/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.