ESTER EN。 LATES 581 21.9 Alkylation of ethyl acetoacetate with 1, 4-dibromobutane gives a product that can cyclize to a five CH3,, CH3 BrCHlCH,CH,CH,Br BrCH, CH, CH, CH,CHCCH3 Ethyl acetoacetate 1.4-Dibromobutane COCHCH NaOCH CH, CCH CCH COCH,CH H2C、 COCH, CH3 Ethyl 1-acetylcyclopentane- Saponification followed by decarboxylation gives cyclopentyl methyl ketone. CCH 1. HO.H,O CCH COCH 3. heat Ethyl l-acetylcyclopentane- carboxylate Cycloketonlemethyl 21.10 The last step in the synthesis of pentobarbital is the reaction of the appropriately substituted deriva- tive of diethyl malonate with urea. CHCH2CH2CH、OcHH CHCH,CH,CH H,NCNH2 CHCH, COCH,CH CH- CH Diethyl 2-ethyl-2-(1-methylbutyl)malonate U Pentobarbital The dialkyl derivative of diethyl malonate is made in the usual way. It does not matter whether the ethyl group or the 1-methylbutyl group is introduced first CH 1. NaoCH CH3, CH, CH,CH, CHCH CH3CH2CH2CH、 CH2(COOCH_ CH3)2 2.NaOCHCHCHCHBT C(COOCH, CH3)2 Diethyl malonate Diethyl 2-ethyl-2-(1-methylbutyl)malonate Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE Website21.9 Alkylation of ethyl acetoacetate with 1,4-dibromobutane gives a product that can cyclize to a five￾membered ring. Saponification followed by decarboxylation gives cyclopentyl methyl ketone. 21.10 The last step in the synthesis of pentobarbital is the reaction of the appropriately substituted deriva￾tive of diethyl malonate with urea. The dialkyl derivative of diethyl malonate is made in the usual way. It does not matter whether the ethyl group or the 1-methylbutyl group is introduced first. CH2(COOCH2CH3)2 Diethyl malonate CH3CH2CH2CH CH3 CH3CH2 C(COOCH2CH3)2 Diethyl 2-ethyl-2-(1-methylbutyl)malonate 2. NaOCH2CH3, CH3CH2Br 1. NaOCH2CH3, CH3CH2CH2CHCH3 Br COCH2CH3 COCH2CH3 CH3CH2CH2CH CH3 CH3CH2 C O O Diethyl 2-ethyl-2-(1-methylbutyl)malonate H2NCNH2 O Urea CH3CH2CH2CH CH3CH2 O N N O O CH3 Pentobarbital H H 1. HO, H2O 2. H 3. heat CCH3 COCH2CH3 O O Ethyl 1-acetylcyclopentane￾carboxylate CCH3 H O Cyclopentyl methyl ketone NaOCH2CH3 ethanol CCH3 O COCH2CH3 O BrCH2CH2CH2CH2CHCCH3 COCH2CH3 O O CH2 CH2 Br H2C C H2C CCH3 O COCH2CH3 O NaOCH2CH3 CH3CCH2COCH2CH3 O O Ethyl acetoacetate BrCH2CH2CH2CH2Br 1,4-Dibromobutane Ethyl 1-acetylcyclopentane￾carboxylate ESTER ENOLATES 581 Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website