Cyclobutane-1,1-dicarboxylic acid

Place 30 g. of cyclobutane-1 1-dicarboxylic acid in a 100 ml. distilling flask, fitted with a thermometer, and connect the side arm to a 60 ml. Claisen flask supported in a funnel so that it can be cooled externally by running water. Heat the distilling flask in a metal bath at 160-170°... 

Phase-transfer conditions are used in the synthesis of cyclobutane-1,1-dicarboxylic acid (13). The pivotal step in this procedure is the initial ring formation to give the intermediate diethyl cyclobutane-1,1-dicarboxylate, which then undergoes subsequent acidic saponification to afford 13. albeit in a meager 23% yield.23 24... 

Decarboxylation reactions of cyclobutanecarboxylic acids appear to pose no particular problems. Cyclobutane-1,1-dicarboxylic acids can usually be decarboxylated thermally at temperatures up to 200 C.1 5> n 340 For example, cyclobutane-1,1,3,3-tetracarboxylic acid was heated to 185 °C at reduced pressure to give a mixture of cis- and frani-cyclobutane-l,3-dicarboxylic acid (l).1 Noteworthy in this reaction is the stereocontrof obtained in the product due to the formation of the anhydride. Generally, decarboxylation will give a mixture of cis- and transacids. The decarboxylation has sometimes been performed in a distillation step.4,5... 

Mercury(II) oxide together with a halogen is an early development of the classic Hunsdiecker reaction (bromodecarboxylation of a carboxylic acid silver salt, see below) which is still in use.20 22 A double Hunsdiecker reaction of cyclobutane-1,1-dicarboxylic acid with red mer-cury(ll) oxide in the presence of bromine gave 1,1-dibromocyclobutane (2) in 46% yield.21 However, a similar reaction performed on spiro[3.3]heptane-2-carboxylic acid afforded 2-bro-mospiro[3.3]heptane (3) in only 16% yield.22... 

A magnetically stirred mixture of cyclobutane-1,1-dicarboxylic acid (1.6 g, 11.1 mmol), HgO (3.3 g, 15.7 mmol), and Br2 (1.14 mL, 3.55 g, 22.2 mmol) in CH2C12 (40 mL) was heated at reflux for 80 min, cooled in an ice bath, treated with pentane (15 mL), and suction filtered. Following rinsing of the filter cake with pentane, the filtrate was concentrated by simple distillation. Pentane was added, the solids were removed by filtration, and the filtrate was washed with 1 M NaOH and brine prior to drying. The pentane was distilled to leave a residue, which in turn was bulb-to-bulb distilled to give the product yield 1.1 g (46%) bp 80-120 "C (bath)/31 Torr. 

Trimethylene dibromide (1 mol) condenses with ethyl malonate (1 mol) in the presence of sodium ethoxide (2 mols) to form ethyl cyclobutane-1 1-dicarboxylate (I). Upon hydrolysis of the latter with alcoholic potassium hydroxide, followed by acidification cyclobutane-1 1-dicarboxylic acid (II) is obtained. 

When cyclobutane 1 1-dicarboxylic acid is heated above its melting point until the evolution of carbon dioxide ceases, cyclobutanecarboxylic acid (III) is formed in good yield ... 

Experiment 7.2 CYCLOBUTANE-1,1-DICARBOXYLIC ACID AND CYCLOBUTANECARBOXYLIC ACID... 

Place 30 g (0.28 mol) of cyclobutane-1,1-dicarboxylic acid in a 100-ml flask fitted with a still-head carrying a thermometer and leading to a cooled receiver flask via a short air condenser. Heat the flask in a Silicone oil bath at 160-170°C until all effervescence ceases. Then raise the temperature of the bath to 210 °C the cyclobutanecarboxylic acid passes over at 191-197 °C. Redistil the acid the pure acid distils at 195-196 °C. The yield of cyclobutanecarboxylic acid (a colourless liquid) is 18 g (86%). 

A series of diamides of cyclobutane-1,1-dicarboxylic acid gre prepared and reported to have depressant properties. The activity of bis 1,1,l-trichloro-2-propyl)-1,2-cyclobutane-dicarboxylate was shown to be due to the in vivo hydrolysis to the known hypnotic 1,1,l-trichloro-2-pro-panol. Preliminary pharmacological results in mice indi-... 

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

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