Cyclobutane-2,4-dicarboxylic acid esters

The compound given in the problem contains three functionalities that can undergo acid-catalyzed hydrolysis an acetal and two equivalent ester groups. Hydrolysis yields 3-oxo-l,l-cyclobutane-dicarboxylic acid and 2 moles each of methanol and 2-propanol. The hydrolysis product is a malonic... 

Alkylation of malonic ester with an equimolar ponion of ethylene bromide or trimethylene bromide produces ring closure to give diethyl esters of 1,1-cyclopropane- and 1,1-cyclobutane-dicarboxylic acids, respectively. Five- and six-membered rings also have been formed in this manner. ... 

Reaction of malonic esters with 1,2-dibromoethane and 1,3-dibromopropane under liquiddiquid two-phase conditions produces the cyclopropane- and cyclobutane- 1,1 -dicarboxyl ic esters, which can be hydrolysed under the basic conditions (6.2.24.C) [e.g. 75, 109] and decarboxylated to give the monocarboxylic acid [e.g. 109]. 

The intramolecular Wurtz-type coupling of dihaloorganic compounds with use of metallic zinc is a classical synthetic route to cyclic compounds. For example, cyclopropane derivatives can be prepared from 1,3-dihalo-propanes (29, 189a, 248, 451), and cyclobutane derivatives from 1,4-dihalobutanes (71). These reactions presumably proceed via the intermediate formation of organozinc compounds. The reaction of diethylzinc with esters of a,a -dibrominated aliphatic dicarboxylic acids leads to the... 

This reaction was initially reported by Franchimont in 1872. It is a condensation of two a-bromocarboxylic acids in absolute alcohol in the presence of sodium cyanide to give 1,2-dicarboxylic acids after hydrolysis and decarboxylation. In the case of a-bromoketones, 1,4-diketones are produced similarly after hydrolysis with phosphoric acid. It was found that the bulky group at the ester end prevents condensation, as in the case of phenyl and naphthyl esters. Although the substituent at j0-position does not prevent such condensation, it reduces the overall yield. In addition, a compound with two ester groups at proper position will form cyclic diacid under such reaction conditions and cyclobutane, " cyclopentane and cyclohexane dicarboxylic acid have been prepared in such a way. In the case of l,4-dibromo-l,4-dibenzoylbutane, a derivative of cyclopentanone is produced after acidic hydrolysis. It should be pointed out that other common solvents—including acetone, ether, and acetonitrile- are not good for this reaction. ... 

A better method used irons-cyclobutane dicarboxylate (7.11) and selective hydrolysis of one ester liberated an acid that could be reduced with borane to give 7.12.2 Conversion of that alcohol to a tosylate was followed by reaction with... 

Ring and open-chain derivatives of L-erythritol 1,4-dicinnamate have been irradiated yielding products of photochemical asymmetric synthesis, in which intramolecular 2-1-2 cycloaddition occurs to give L-erythritol esters of cyclobutane-1,2-dicarboxylic acid the 2,3-di-O-methyl derivative of l-erythritol gave a high degree of asymmetric induction, whereas the 2,3-0-isopropylidene derivative was much less stereospecific, and gave the opposite cyclobutane enantiomer. ... 

C10H16O4 cyclobutane-1,1-dicarboxylic acid diethyl ester 3779-29-1... 

Diacids.—Succinic acid derivatives can be obtained in good yields by coupling lithium a-lithiocarboxylates (or ester enolates) with lithium a-halocarboxylates, or a-halo-esters/ Carboxylic acid dianions also react with isocyanates and iso thiocyanates to give malonamic acids (13 X = O) and 3-thiomalonamic acids (13 X = S), respectively/ A route to c/5-cyclobutane-l,2-dicarboxylic acids (16), which could be of some generality, consists of photocyclization of acryl-imides (14) to maleimides (15) and hydrolysis/ Yields of (15), as judged by n.m.r. spectra, are between 45 and 82%. 

Cyclic amino acids 139, when heated in acetic anhydride, probably form initially mesoionic oxazolium 5-oxides (munchnones) subsequent 1,3-dip olar cycloaddition of 1,2-dicyanocyclobutene, loss of carbon dioxide, and opening of the cyclobutane ring lead to dinitriles 140 (80JHC1593). Pyridone 141 is the by-product (together with an indolizine) of the mono-cyclic pyridone dicarboxylate and acrylic ester (73JHC77). 

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