PROCESS FOR THE PREPARATION OF KETOALKYNOIC ACIDS AND USE OF THE PROCESS IN A SYNTHESIS OF 2-(SUBSTITUTED)-CYCLOPENTANE-1,3,4-TRIONES

摘要

1530535 Ketoalkynoic acids MILES LABORATORIES Inc 21 Feb 1977 [23 Feb 1976] 07260/77 Heading C2C The invention comprises a process for preparing keto alkynoic acids or esters of formula wherein n is 1-8, and R is hydrogen or alkyl (1-3 C) by reacting 2-methyl-2-(3-butynyl)- 1,3-dioxolane with a -#-dihalogeno alkane, Br-(CH 2 ) n Cl or I-(CH 2 ) n -Cl in liquid ammonia in the presence of alkali-metal amide to obtain a 2-methyl-2-(#-chloroalkynyl)-1,3-dioxolane converting to the nitrile, hydrolysing to the acid and esterifying if required. The acids may be reduced to the corresponding keto-cis-alkenoic acid, esterified and condensed with a di(alkyl)- oxalate (CO 2 RSP1/SP) 2 in the presence of an alkali metal alkoxide, to obtain a 2-(substituted)-5- alkoxalyl-cyclopentane-1,3,4-trione where RSP1/SP is C 1-3 alkyl which is hydrolysed to the 2-substituted-cyclopentane-1,3,4-trione. The invention further comprises the compounds of Formula XII and the compounds of the formula