1,1-Cyclobutanedicarboxylic acid, with

CHLORO-,51, 73 1,1-Cyclobutanedicarboxylic acid, with sulfuryl chloride to give 3-chloro-1,1-cyclobutanedicarboxylic acid, 51,73... 

If this extraction with ether is omitted the yield of 1,1-cyclobutanedicarboxylic acid is 3-4 g. less. 

The submitters used 55 cc. of hydrochloric acid at this point the checkers stated that this amount was insufficient to neutralize the mixture. The purpose of acidification at this point is not to liberate the cyclobutanedicarboxylic acid, but merely to remove carbonates and excess potassium hydroxide. After the carbon dioxide has been expelled, the solution is made alkaline with ammonia hence a great excess of hydrochloric acid should be avoided. The submitters used only enough hydrochloric acid to make the solution acid to litmus. After the solution has been made basic with ammonia, barium chloride solution is added until there is no further precipitation of barium malonate. 

Cyclobutanedicarboxylic acid has been prepared by hydrolysis of the ethyl ester,1 or of the half nitrile, 1-cyano-l-car-boxycyclobutane.2 The ethyl ester has been prepared by condensation of ethyl malonate with trimethylene bromide1 or chloro-bromide.3 The half nitrile has been prepared by condensation of trimethylene bromide with ethyl cyanoacetate followed by hydrolysis of the ester to the acid.2... 

Sulfonium, cyclopropyldiphenyl tetrafluoroborate, 54, 28 Sulfonium salts, acetylenic, furans from, 53, 3 Sulfonium ylides, 54, 32 Sulfur, reaction with organo-lithium compounds, 50, 105 Sulfuryl chloride, with 1,1-cyclobutanedicarboxylic acid to give 3-chloro-l,1-cyclobutanedicarboxylic acid, 51, 73... 

Many platinum analogs, and analogs based on other metal centres, have been prepared and evaluated. Carboplatin (7.89, cA-diammine(l,l cyclobutanedicarboxalato)platinum) has markedly reduced gastrointestinal and renal toxicity in comparison with cisplatin. It is prepared by the treatment of cA-Pt(NH3)2l2 with silver sulphate, followed by the barium salt of 1,1-cyclobutanedicarboxylic acid. 

In the very early years of imprinting, carboxylic acid ester moieties were used as binding groups. The aim was the preparation of microreactors for regio- and stereoselective reactions. For this, the cavity was first imprinted with a possible product of the reaction and a precursor was then embedded into the cavity. The idea was to favour the formation of the product used as template by running the reaction within the imprinted cavity. The first experiments were carried out by the research groups of Shea [90,91] and Neckers [92], who performed cycloadditions that led to cyclo-propanedicarboxylic and cyclobutanedicarboxylic acids, respectively. The latter... 

Another organometallic platinum drug has been approved in the United States. It is a diammin platinum coordinate with 1,1-cyclobutanedicarboxylic acid named carboplatin (CBDA, Paraplatin). Its advantages over cisplatin are a lesser emetogenic effect as well as a possible decrease in nephro- and ototoxicity. 

The energy difference between puckered and planar conformations in cyclobutanes appears to be small. The geometries of many-substituted cyclobutanes in the crystal have been determined to be planar by X-ray diffraction, trans-1,3-Cyclobutanedicarboxylic acid, when crystallized by itself, has a planar four-membered ring, but, when cocrystallized with its disodium salt, has a puckered four-membered ring. ... 

Shea and co-workers (109,110) were the first to try this approach. They prepared polymers from the optically active (-)-trans-l,2-cyclobutanedicarboxylic diester 15 and obtained cavities after splitting off the template containing two benzyl alcohols each. To these cavities fumaric acid could be bound. It was reacted with a methylene-transfer reagent [(dimethylamino)methyl-phenyl-oxosulfonium tetrafluoroborate]. The cyclopropanedicarb-... 

The kinetic behavior of the anticancer drug Carboplatin, [Pt(NH3)2(biL)] (biL = 1,1-cyclobutanedicarboxylate), has been examined. In the absence of acid and other nucleophiles, the complex is quite inert. With addition of chloride. 

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