Perfluorotricyclic Amines as Oxygen Carriers

This invention relates to a novel perfluorotricyclic amine compound useful as an oxygen carrier in artificial blood or in an infusion fluid.

More particularly, it relates to a perfluorotricyclic amine compound represented by the general formula ##STR2## wherein k, j, l and m are zero or an integer of from 1 to 3, and n is an integer of from 1 to 3, the rings A, B and C being optionally substituted with at least one trifluoromethyl group.

Regarding the general formula (I), it is preferable that the ring A is selected from five- to seven-membered rings, the ring B from five- to eight-membered rings, and the ring C from five- to eight-membered rings. The total number of the carbon atoms contained in the compound of formula (I) is preferably from 9 to 12.

In detail, the first series of the present perfluorotricyclic amine compounds without optional substituent of --CF.sub.3 is represented by the formula, ##STR3## wherein k is an integer of 1 or 2; l, m and n are zero or an integer of 1 or 2. The compound has preferably 10 to 12 carbon atoms in total.

The second series is also represented by the formula, ##STR4## wherein k and n are an integer of 1, 2 or 3; l and m are zero or an integer of 1, 2 or 3. The compound has preferably 10 to 12 carbon atoms in total.

The third series is also represented by the formula, ##STR5## wherein k and j are zero or an integer of 1; l, m and n are zero or an integer of 1 or 2. The compound has preferably 10 to 12 carbon atoms in total.

The fourth series is also represented by the formula, ##STR6## wherein l and m are zero or an integer of 1, 2 or 3; n is an integer of 1, 2 or 3.

The compound may have at most two trifluoromethyl groups and its total number of carbon atoms are preferably 9 to 12 in case of no substituent and 10 to 11 depending on the substituted number of the trifluoromethyl group.

The compound of formula (I) can be prepared by fluorinating a perhydro-compound corresponding to the compound of formula (I). The methods of fluorination include, for example, a direct fluorination, a fluorination by use of cobalt trifluoride, and an electro chemical fluorination.

The preparation of the compound of formula (I) of this invention is preferably performed by the electrochemical fluorination method. This is performed, for example, by mixing anhydrous hydrogen fluoride and the perhydro-compound used as the starting compound in an electrolytic cell and subjecting the resulting solution to electrolysis. The voltage, the current density at the anode, and the temperature of electrolytic solution are normally 3-9 V, 0.1-10 A/dm.sup.2 and 4.degree.-12.degree. C., respectively.

The compound of formula (I) thus formed was drained from the bottom of the cell, being insoluble in anhydrous hydrogen fluoride.

The isolation and purification of the compound from the drained product are carried out, for example, by adding a mixture of equal volumes of an aqueous caustic alkaline solution and an amine compound to the drained product and refluxing to decompose partially fluorinated compounds. After cooled, the lowermost layer containing the desired compound of formula (I) is separated, washed with an aqueous acetone solution containing a suitable amount of potassium iodide to remove perfluoroalkyl nitrogen fluorides, and subjected to fractional distillation to obtain the fraction of the desired compound of formula (I).

Since the compound of the formula (I) of this invention can not only dissolve a large amount of oxygen, and is chemically and biologically inert, but also it can be excreted rapidly from the body, it can form, for example, an aqueous emulsion containing 5 to 50, preferably 10-40, % (W/V) of the compound of formula (I) to be used as an oxygen carrier in an artificial blood or in an infusion liquid for men and other mammals such as dogs, cats, cattle, mice, rats and guinea pigs.

The symbol "%(W/V)" referred to herein mean the amount of the material by weight (gram) based on 100 ml of the resulting emulsion.

In the preparation of the emulsion mentioned above, there used, as an emulsifier, a nonionic surfactant and/or phospholipids in an added amount of 1 to 5% (W/V).

As the medium for the emulsion, a physiologically acceptable aqueous solution is employed. If necessary, there may be added thereto such materials as glycerol to provide the desired isotonicity, and such plasma expanders as HES or dextran to regulate the colloid osmotic pressure of the emulsion.

The emulsion can be prepared by mixing the above-mentioned ingredients and homogenizing the mixture by means of, for example, a high-pressure jet type homogenizer until the particle diameters become 0.05 to 0.3 .mu.m, preferably less than 0.2 .mu.m.

The perhydro-compounds (starting compounds) corresponding to the compounds of formula (I) are substantially known already.

Into an electrolytic cell made of Monel metal with an inner volume of 1.5 l, which is provided with electrode plates (six plates as anode and seven plates as cathode) made of nickel (purity: 99.6% or higher) arranged alternately with an inter-electrode distance of 1.7-2.0 mm, the effective anode surface area being 10.5 dm.sup.2, and with a reflux condenser made of copper at the upper part of the cell, was introduced 1.2 l of anhydrous hydrogen fluoride, and trace amounts of impurities present in the system (moisture and sulfuric acid) were removed by preliminary electrolysis. Then, 0.86 mol (130 g) of 2-azatricyclo[5,3,1,0.sup.2,6 ]-undecane was dissolved into the anhydrous hydrogen fluoride, and electrolysis was carried out, while introducing helium gas from the bottom of the cell at a rate of 100 ml/min., under the conditions of anode current density of 0.4-2.0 A/dm.sup.2, voltage of 5-9 V and solution 7.degree.-12.degree. C., until the electrolytic voltage had reached 9.0 V. The ampere-hours amounted to 975. Hydrogen fluoride was added at a rate of 250 ml per 24 hours during the electrolysis. No attempt was made to collect volatile products formed by a bond breaking reaction, which would give more yields of the desired product. After completion of the electrolysis, fluorocarbons in the lower layer in the cell was drained through the bottom of the cell, weighed 265 g (58% yield).

To the fluorocarbons thus separated, were added equal volumes of 70% aqueous potassium hydroxide solution and diisobutylamine, and the resulting mixture was refluxed for about five days. The reaction mixture was then cooled in an ice bath, and filtered by suction. The perfluoro-compounds sedimented in the lowermost layer were separated in a separatory funnel, washed successively with diluted sulfuric acid, concentrated sulfuric acid, saturated aqueous sodium hydrogen carbonate solution, 90% aqueous acetone solution containing 3% of potassium iodide, and water to yield 110 g of a transparent perfluoro-compounds containing no protons. This was distilled on a fractional distillation apparatus equipped with a spinning band column to afford 33 g (7% yield) of the desired product boiling at 143.degree.-152.degree. C. This product was collected, purified, and then analyzed by infrared absorption spectrometry, .sup.19 F-nuclear magnetic resonance spectrometory and mass spectrometory, and was confirmed to be the objective compound, perfluoro-2-azatricyclo[5,3,1,0.sup.2,6 ]-undecane of which chemical structure is shown in Table 1 as compound No. 1.

A series of other perfluorotricyclic amine compounds having the formulas (II and V), wherein j is 1 was synthesized from perhydrotricyclic amine compounds each corresponding thereto and purified in the same manner as that described above and each product was confirmed to be the objective compound upon analysis by infrared absorption spectrometory, .sup.19 F-nuclear magnetic resonance spectrometory and mass spectrometory.

The structural formula and the boiling point of each of the objective compounds as well as the starting compounds are shown in the Table 1. The symbol "F-" in the structural formula indicates that the compound is perfluorinated. For example, the formula ##STR7## indicates in its exact meaning the formula ##STR8##

A series of perfluorotricyclic amine compounds of the formula (IV) wherein j is 2 or 3 was synthesized, purified and confirmed to be the objective compound in the same manner as in Example 1.

The structural formula and the boiling point of each of the objective compounds are shown in the Table 2. The symbol "F-" in the structural formula indicates that the compound is perfluorinated. For example, the formula ##STR142## indicates in its exact meaning the formula ##STR143##

A series of perfluorotricyclic amine compounds of the formula (III) wherein j is zero was synthesized, purified and confirmed to be the objective compound in the same manner as in Example 1.

The structural formula and the boiling point of each of the objective compounds is shown in the Table 3. The symbol "F-" in the structural formula indicates that the compound is perfluorinated. For example, the formula ##STR166## indicates in its exact meaning the formula ##STR167##