Cyclopropane dicarboxylic acid

The procedure (with ethylene dibromide replacing trimethyleiie dibromide) described for cycZobutanecarboxylic acid (previous Section) does not give satisfactory results when applied to the cyclopropane analogue the yield of the cyclopropane-1 1 dicarboxylic acid is considerably lower and, furthermore, the decarboxylation of the latter gives a considerable proportion (about 30 per cent.) of butyrolactone ... 

It is noteworthy that in the synthesis of 117, the smaller Ugi macrocycle 118 was also formed. The lack of sterically demanding isopropyl groups in comparison to 113 allows the formation of this somewhat strained macrocycle. Because of this intriguing result, the diacid component in this reaction was varied to cyclopropane-1,1-dicarboxylic acid (Scheme 24) and tereph-thalic acid (Scheme 25). 

Cyclopropane-1,1-dicarboxylic acid [598-10-7] M 130.1, m 140 . Recrystd from CHCI3. 

A. Preparation of cyclopropane 1,1 -dicarboxylic acid (1). To a 1-L solution of aqueous 50% sodium hydroxide (Note 1), mechanically stirred in a 2-L, three-necked flask, was added, at 25°C,... 

Previously cyclopropane-1,1-dicarboxylic acid had been prepared2-4 by hydrolysis of the corresponding diester. The preparation of 1,1-dicarboalkoxycyclopropanes by a conventional double alkylation of diethyl malonate with 1,2-dibromoethane was severely complicated by the recovery of unreacted diethylmalonate. This required a rather difficult distillation to separate starting material and product. In fact, many commercially offered lots of cyclopropane diester contain extensive amounts of diethyl malonate. Furthermore, preparation of the diacid required a separate and relatively slow saponification of the diester.5... 

By carefully designing the structure of bifunctional substrates, Wessjohann developed a fourfold Ugi-4CR for the syntheses of large ring-size macrocycles. Thus, the reaction of diamine 67, cyclopropane-1,1-dicarboxylic acid (72), isopropylamine and formaldehyde afforded 48-membered macrocycle 73 in 49% yield (Scheme 21). It is appropriate to note herein that a yield of 49% corresponds to an approximately 96% calculated yield for each individual bond-forming process, including the macrocyclization step. 

Asymmetric synthesis of cyclopropanes, The reaction of dimethyloxosnifonium methylide with (E)-(2R,3S)-6-alkylidene-3,4-dimethyl-2-phenylperhydro-l,4-oxazepine-5,7-diones (1) yields cyclopropane derivatives (2) and dihydrofuranes (3). The ratio of the products depends on the solvent and temperature. Use of THF at 25° favors formation of 2, whereas formation of 3 is favored by use of DMF at -61°. The products (2 and 3) can be converted into optically pure cyclopropane-1,1-dicarboxylic acids (4) and 3-substituted y-butyrolactones (5), respectively. 

To a stirred solution of 50% aq NaOH (30 mL) was added triethylbenzylammonium chloride (TEBAC) (3.54 g, 15 mmol) followed by diethyl malonate (2.40 g, 15 mmol) and 1,2-dibromoethane (4.23 g, 23 mmol). The mixture was stirred for 1 h. After dilution with H2O (75 mL), the system was extracted with EtjO. The aqueous layer was acidified with coned aq HCl and extracted with EtjO. The organic layer was washed with brine and dried (MgSOJ. Evaporation of the solvent gave cyclopropane-1,1-dicarboxylic acid yield 1.74 g (75%) mp 134-136 C. 

Dibromocyclopropane is obtained in 36% yield from the reaction of cyclopropane-1,1-dicarboxylic acid with bromine and mercuric oxide in refluxing dichloromethane. ... 

Various cyclopropanecarboxylic acids and esters have been converted to various amides, TV-alkylated amides, and hydrazides by treatment with ammonia, alkylamines, - and hydrazines, respectively. In many cases the acids have been converted via the corresponding acid chlorides generated in situ. Diethyl esters of a variety of cyclopropane-1,1-dicarboxylic acids also react with urea. Generally, all these reactions proceed smoothly and in fairly good yield and give only very small amounts of byproducts due to opening of the cyclopropane ring. 

Cyclopropane-1,1-dicarboxylic acid (30a) reacted with hydrobromic acid to (2-bro-moethyl)malonic acid (31a) . In a similar reaction, ethyl 1-acetylcyclopropane-l-carboxylate (31b) ( C enriched) was converted to 5-bromopentan-2-one upon treatment with hydrobromic acid and decarboxylation." In 2-benzoyl-3-phenylcyclopropane-1,1-dicarboxylic acid (31c), two different activating functions are present and can influence the addition of hydrogen bromide. In fact, products arising from the cleavage of either bond that link the phenyl-substituted carbon were isolated. Both primary products had lost hydrogen bromide and carbon dioxide. 

Cyclopropane-1,1-dicarboxylic acid. This compound can be obtained in high yield by double alkylation of diethyl malonate with 1,2-dibromoethane under phase-transfer conditions. Malonic acid cannot be alkylated in this way. 

Homoconjugate reactions. In comparison to cyclopropane-1,1-dicarboxylic acid, the cyclic acylal (1) shows pronounced double-bond character in reactions with nucleophiles. Thus it reacts with piperidine in benzene at 20° to give the zwitterion (2) in quantitative yield. The second reaction (II) is an example of the... 

Early gas-phase studies (reviewed in Reference 50) and X-ray analyses of cyclopropanecarbohydrazide 2,5-dimethyl-7,7-dicyanonorcaradiene and cyclopropane-1,1-dicarboxylic acid provided experimental evidence for the predicted bond-length asymmetry in Cp and for the approximate validity of the additivity principle. The magnitude of d was indicated to be ca 0.015-0.025 A for —C=0, —C=N. A more rigorous attempt to quantify for various substituents made use of 299 relevant substructures available in the X-ray literature in 1980. This work yielded -values of 0.026(5), 0.022(4) and 0.017(2) for —C=0, —C=C, and —C=N substituents, respectively, and clearly implicated a number of other groups in effective conjugative interactions. 

Cyclopropane-1,1-dicarboxylic acid, cyclopentane-l,l-dicarboxylic acid, and cyclohexane-1,1-dicarboxylic acid 884... 

A study of the hydrogen bond strength in the monoanion of cyclopropane-1,1-dicarboxylic acid has reaffirmed the view that this bond strength is not necessarily related to the angle between the two acid functions. The influence of a cyclopropyl group attached to the chiral centre of an optically active molecule on the optical rotation has been shown to be greater than that of a methyl group but lower than that of a pentyl function. ... 

See Cyclopropane-1 1-dicarboxylic Acid. Ethylene oxide Oxirane)... 

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