The Identification of Aromatic Sulfonic Acids Containing an Amino Group

Abstract

Aromatic sulfonic acids are readily identified in most schemes of qualitative organic analysis (1) by formation of the sulfonamide. A less familiar method is the production of salts between the acids and amines, or amine derivatives (2-11). Where applicable, this latter procedure gives results in a much shorter time. Neither of these means of identification is applicable to sulfonic acids when there is an amino group present.1 Inner salt formation prevents the use of the second procedure, and the sensitivity of the amino group to phosphorus pentachloride makes impossible the application of the first method.However, it has been found that when many aromatic sulfonic acids containing one amino group are diazotized and the NH2 replaced by Cl by means of the Sandmeyer reaction, the resulting chlorosulfonic acid is

Lanthanides in organic synthesis. Samarium metal promoted selective formation of azoxy compounds

“…With use of standard reaction conditions and workup, dragmacidin (la, 20 mg, 0.003 mmol) was treated with excess acetic anhydride and pyridine overnight and at room temperature. The residue was purified by chromatography on silica gel to obtain the triacetate lb (9.0 mg, 42%): NMR (acetone-d6) S 10.75 (br s, 1 H), 8.63 (d, 1 H, J = 1.8 Hz), 7.75 (d, 1 H ,J= 8.6 Hz), 7.68 (s, 1 H), 7.65 (br s, 1 H), 7.45 (dd, 1 H, J = 1.8, 8.6 Hz), 7.23 (s, 1 ) 5.80 (m, 1 H), 4.17 (m, 1 H), 4.02 (m, 2 ), 3.31 (dd, 1 H, J = 5.4, 12.4 Hz), 2.92 (dd, 1 H, J = 6.1, 12.4 Hz), 2.67 (s, 3 H), 2.43 (s, 3 H), 2.29 (s, 3 ), 2.08 (s, 3 H); FABMS, m/z (relative intensity, bromine composition) 708 (M+, 48, Br3), 666 (34,Br3), 588 (22,Bra), 388 (11,Br2), 357 (17,Br2),346 (13,Br2),333 (18,Br2), 320 (45, Br), 304 (9,Br2), 291 (100,Br2), 278 (53,Br),236 (38,Br), 221 (12,Br),195 (20,Br); HREIMS, m/z 705.9406, C27H26N404Br3, -2.8 mmu.…”