Sulfonation of substituted azoles with sulfur trioxide in dichloroethane

A novel method has been developed for the synthesis of sulfonic acids of five-membered heterocycles containing two heteroatoms, with a solution of sulfur trioxide in 1,2-dichloroethane. High yields of the required products are obtained, under conditions which are mild in comparison with those used in earlier methods. The mechanism of sulfonation is discussed, and some azole·SO₃ complexes have been obtained and described.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1353–1359, October, 1987.     

Synthesis and Structure of Tetraphenylantimony Nitrite

Tetraphenylantimony nitrite was synthesized by reacting pentaphenylantimony with triphenylantimony dinitrite at a molar ratio of 1 : 1 in toluene, and its structure was determined using X-ray diffraction analysis. The Sb atom is coordinated to the oxygen atom of the axial nitrite group to form a trigonal bipyramid. The Sb–C(Ph)_eq distances vary within the 2.103–2.111(3) Å range, and the S–O(1) and Sb–C(41) bond lengths are equal to 2.386(3) and 2.156(3) Å, respectively. The Sb...N distance and the axial C(41)SbO(1) angle are equal to 3.133(4) Å and 174.7(1)°, respectively.     

Phenylation of Antimony(V) Organic Compounds with Pentaphenylantimony. The Structure of Tetraphenylantimony Chloride

Tetraphenylantimony chloride and bromide were synthesized through the reaction of pentaphenylantimony with diphenylantimony trichloride or tribromide taken at a molar ratio of 2 : 1 in toluene. When the initial compounds were taken at a molar ratio of 1 : 1, triphenylantimony dichloride or dibromide was formed. The phenylation of triphenylantimony sulfate with pentaphenylantimony yielded tetraphenylantimony sulfate. According to the X-ray diffraction data, the antimony atom in the tetraphenylantimony chloride molecule has a distorted trigonal bipyramidal configuration with the chlorine atom in the axial position. The Sb–Cl distance is equal to 2.686(1) and Sb–C distances are equal to 2.113(4) and 2.165(4) Å (av. 2.130 Å).     

Synthesis and Structure of Tri-p-tolylantimony Ditosylate

Tri-p-tolylantimony reacts with p-toluenesulfonic acid in the presence of benzoyl peroxide (1 : 2 : 1 molar ratio) in ether to give tri-p-tolylantimony ditosylate in 91% yield. According to X-ray diffraction data, the central antimony atom has the trigonal bipyramidal coordination with the axial location of the tosyl groups. The Sb-O bond lengths are 2.07(2) and 2.17(2) Å; Sb-C bond lengths, 2.08(3), 2.13(3), and 2.13(3) Å; and OSbO bond angle, 175.6(7)°.     

Synthesis and Structure of 2-tert-Butylphenoxytetraphenylantimony

2-tert-Butylphenoxytetraphenylantimony Ph₄SbOC₆H₄(Bu-t)-2 was prepared by the reaction of pentaphenylantimony with 2-tert-butylphenol in toluene at 20°. The structure of the obtained compound was determined by X-ray diffraction. The Sb atom in this compound has a distorted trigonal-bipyramidal coordination with the aroxy group in the axial position. The Sb–C(Ph)_eqand Sb–C(Ph)_axdistances are 2.111(7)–2.138(7) and 2.180(7) Å the Sb–O and O–C_Ardistances are 2.143(4) and 1.363(8) Å, respectively. The C(Ph)_axSbO_Araxial angle is 174.1(2)°, while the SbOC angle is 126.7(4)°.