Room Temperature Ionic Liquids from Purine and Pyrimidine Nucleobases

Abstract

Purine and pyrimidine nucleobases are of central attraction in biological and chemical sciences as these bases or their derivative are primary components in genetic materials. The solubility of these components is the main concern and puts certain limitations on their use in laboratory synthesis of medicinally important molecules. In this work, efficient conversions of purine and pyrimidine nucleobases (namely uracil, thymine, adenine, guanine, xanthine and hypoxanthine) into corresponding completely water soluble salts are reported. All the reported salts are room temperature ionic liquids except xanthine salts which have melting points higher than 100 °C and hence cannot be called as ionic liquids. Synthesized room temperature ionic liquids from nucleobases were well characterized using spectral and thermal analysis. Experimental data of some physicochemical properties such as density, conductivity, glass transition temperature, melting temperature as well as decomposition temperature reported which shows that the reported ionic liquids are stable upto 200 °C.

Applications of Ionic Liquids in Carboxylic Acids Separation

“…Several carboxylic acids have been separated using ionic liquids (Table 3). For butyric acid, reactive extraction using [P6, 6,6,14] [Phos] trihexyl tetradecyl phosphonium di-2,4,4 trimethylpentyl phosphinate and [CnCnCnC1N] [Phos], trialkylmethy-lammonium bis (2,4,4-trimethylpentyl) phosphinate resulted in a distribution coefficient equal to 80 for low concentrations of butyric acid, the formed complex involving 12 water molecules per ion pair of the IL [109].…”

“…These organic salts with outstanding properties in different fields (Figure 1) have become of major interest to scientists involved in a diverse suite of specializations [2][3][4]. Bio-based ILs have as precursors choline, glycinebetaine (N,N,N-tri (methyl) (2-dodecyloxy-2-oxomethyl)-1-ammonium docusate; N,N,N-tri (methyl) (2-dodecyloxy-2-oxomethyl)-1-ammonium thiocyanate [5]), purine and pyrimidine nucleobases (1-n-alkyl-3-methylimidazolium based nucleobases ionic liquids [6]), carbohydrates (D-xylose derived imidazolium-based chiral ionic liquids [7]), amino acids ( [Cho] [AA] ILs [8]), organic acids (protic ionic liquids based on strong organic acids: trifluoracetate, methanesulfonate, and triflate of triethylammonium [9]) and can be a more economical solution for industrial separations.…”

Aqueous Biphasic Systems Comprising Natural Organic Acid-Derived Ionic Liquids

“…Although less investigated, bio-based ILs may help overcome the high cost of conventional imidazolium-based ILs while improving the green features of this class of solvents [11,12]. Examples of bio-based ILs comprise those based on at least one of the following precursors: choline [13,14], glycine-betaine [15,16], guanidine [17,18], purine and pyrimidine nucleobases [19], carbohydrates [20,21], amino acids [14,22], organic acids [13,23], fatty acids [24,25], and terpenes [26,27]. Thus far, ILs bearing a cholinium cation combined with natural acid-derived anions are the most studied and used as proteinfriendly options in IL-based ABSs [28][29][30][31].…”

Synthesis of Purine-Based Ionic Liquids and Their Applications

“…They often do not fulfill more than just a few of the twelve principles of green chemistry [7,9]. Aiming to fulfill the 7th and 10th principles of green chemistry [9] (namely the use of renewable feedstock and design for degradation, respectively), the use of natural and renewable building blocks for the design of ILs is being increasingly targeted [10][11][12][13][14]. Among these, organic acids [10], natural sugars [11], amino acids [12], terpenes [13], and purines [14] are some examples of the natural building blocks used for their synthesis.…”

“…By using purines as feedstock, it may be possible to design novel, bio-based ILs, while simultaneously increasing the purine solubility. Gavhane et al [14] were able to accomplish this through the synthesis of water-soluble ILs, based on purines, by using 1-n-alkyl-3-methylimidazolium as a cation and adenine, guanine, hypoxanthine, or xanthine as anions. As the design of ILs based on purines seems to eliminate the solubility obstacles for the use of purines in aqueous solution, it becomes possible to conceive of novel applications for purine-based salts.…”