8769. Squaric Acid
Nomenclature
Description and references
Dibasic acid; two-dimensional molecular antiferroelectric material. Prepn: S. Cohen et al., J. Am. Chem. Soc. 81, 3480 (1959); J. D. Park et al., ibid. 84, 2919 (1962). Aqueous dissociation study: L. M. Schwartz, L. O. Howard, J. Phys. Chem. 74, 4374 (1970). Structure determn studies: D. Semmingsen, Acta Chem. Scand. 27, 3961 (1973); Y. Wang et al., J. Chem. Soc. Perkin Trans. 2 1974, 35. Review of syntheses and reactivity: G. Maahs, P. Hegenberg, Angew. Chem. Int. Ed. 5, 888-893 (1966); of coordination chemistry: L. A. Hall, D. J. Williams, Adv. Inorg. Chem. 52, 249-291 (2001).
Properties
Crystals from water, dec 293°. d 1.90. uv max (H2O): 269.5 nm (ε 37000). Soly: 7% boiling water; 2% room temp water. Insol in acetone, ether. pK1 ~0.6 (25°). pK2 3.480 ±0.023 (25°).Derivative
Dibutylester.Nomenclature
Description and references
Prepn: G. Maahs, Ann. 686, 55 (1965). Clinical evaluation in alopecia: G. Micali et al., Int. J. Dermatol. 35, 52 (1996); in treatment of warts: idem et al., Pediatr. Dermatol. 17, 315 (2000).
Properties
bp0.5 138-139°. nD20 1.4943.Use
Squaric acid and its derivatives are used in synthesis of pharmaceutical intermediates, squarylium dyes, and photoconducting squaraines.Therapeutic Category
Dibutylester as contact sensitizer for treatment of alopecia and warts.
Keywords
Squaric Acid Dibutylester: Antialopecia Agent