Improved synthesis of 3-aryl isoxazoles containing fused aromatic rings.

A critical comparison of methods to prepare sterically hindered 3-aryl isoxazoles containing fused aromatic rings using the nitrile oxide cycloaddition (NOC) reveal that modification of the method of Bode, Hachisu, Matsuura, and Suzuki (BHMS), utilizing either triethylamine as base or sodium enolates of the diketone, ketoester, and ketoamide dipolarophiles, respectively, was the method of choice for this transformation.

New adjuvants to enhance anticoagulant activity of warfarin.

New adjuvants of warfarin anticoagulant activity have been developed. These compounds, which are 1,4-methano-1,2,3,4-tetrahydroanthracene-9,10-diol derivatives, act synergistically with warfarin to potentiate its anticoagulant effect. None of the compounds tested is an effective oral anticoagulant in the absence of warfarin.

Low melting N-4-functionalized-1-alkyl or polyfluoroalkyl-1,2,4-triazolium salts.

Butane sulfobetaines 2a,b, zwitterionic oxo perfluorocarboxylates 3a,b, and functionalized triazolium bromides 4b,c and 5a-c have been synthesized and subsequently reacted to give a series of hydrophilic and hydrophobic fluorinated and nonfluorinated N-1-alkyl-N-4-functionalized-triazolium compounds (6a-11b). With the exception of 11b (mp 41 degrees C), all are liquids at room temperature. Metathesis of the fluorinated quaternary triazolium halides with other anions led to the formation of a new class of compounds, namely, [(R)(R(funct))-Taz](+)Y(-), Y = PF(6), (CF(3)SO(2))( 2)N, and CF(3)SO(3), in good isolated yields. All of the new compounds were characterized by (1)H, (19)F, and (13)C NMR, and MS spectral and elemental analyses. Thermal analyses indicate that high temperatures are attainable prior to decomposition. DSC studies show glass transitions for several samples, and all functionalized compounds, 5-11, have T(g)s or T(m)s <100 degrees C. Densities range between 1.4 and 1.61 g cm(-)(3). 1-Heptyl-4-(butyl-4-sulfonic acid) triazolium trifluoromethanesulfonate, 6b, in its role as a Brønsted acid, is an effective solvent/catalyst for high yield esterification and hetero-Michael addition reactions and may be recycled for repetitive use.

Syntheses of 1-alkyl-1,2,4-triazoles and the formation of quaternary 1-alkyl-4-polyfluoroalkyl-1,2,4-triazolium salts leading to ionic liquids.

1,2,4-triazole was alkylated (alkyl = methyl, butyl, heptyl, decyl) at N-1 in >90% isolated yields. The resulting 1-alkyl triazoles were quaternized at N-4 in >98% isolated yields using fluorinated alkyl halides with >98% isolated yields, under neat reaction conditions at 100-120 degrees C to form N1-CH(3)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-triazolium (Taz) iodide (m = 1, 6), N1-C(4)H(9)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-Taz iodide (m = 1, 4, 6), N1-C(7)H(15)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-Taz iodide (m = 1, 4, 6), N1-C(10)H(21)-N4-(CH(2))(2)C(m)F(2)(m)(+1)-Taz iodide (m = 1, 4), and N1-C(n)H(2)(n )(+ 1)-N4-(CH(2))(2)F-Taz bromide (n = 4, 7, 10). Single-crystal X-ray analyses confirmed the structure of [1-CH(3)-4-CH(2)CH(2)CF(3)-Taz](+)I(-). It crystallized in the orthorhombic space group Pccn, and the unit cell dimensions were a = 13.8289(9) A, b = 17.3603(11) A, c = 9.0587(6) A (alpha = beta = gamma = 90 degrees ). Metathesis of these polyfluoroalkyl-substituted triazolium halides with other salts led to the formation of quaternary compounds, some of which comprise ionic liquids, namely, [R(R(f))-Taz](+)Y(-) (Y = NTf(2), BF(4), PF(6), and OTf), in good isolated yields without the need for further purification: N1-CH(3)-N4-(CH(2))(2)C(m)F(2)(m)( +) (1)-Taz Y (m = 1, 6; Y = NTf(2)), N1-C(4)H(9)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-Taz Y (m = 1, 4, 6; Y = NTf(2)), N1- C(7)H(15)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-Taz Y (m = 1, 4, 6; Y = NTf(2)), N1-C(10)H(21)-N4-(CH(2))(2)C(m)F(2)(m)(+1)-Taz Y (n = 1, 4; Y = NTf(2)), N1-C(n)H(2)(n )(+ 1)-N4-(CH(2))(2)F-Taz Y (n = 7, 10; Y = NTf(2)), N1-C(10)H(21)-N4-(CH(2))(2)F-TazY (Y = OTf), N1-C(7)H(15)-N4-(CH(2))(2)F-TazY (Y = BF(4)), N1-C(4)H(9)-N4-(CH(2))(2)C(m)F(2)(m) (+ 1)-Taz Y (m = 4, 6; Y = PF(6)), N1-C(7)H(15)-N4-(CH(2))(2)C(4)F(9)-Taz Y (Y = PF(6)), N1-C(4)H(9)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-Taz Y (m = 4, 6; Y = OTf). All new compounds were characterized by (1)H, (19)F, and (13)C NMR and MS spectra and elemental analyses. T(g)s and T(m)s of ionic liquids were determined by DSC.