Aromatic Isocyanates as Reagents for the Identification of Some Heterocyclic Compounds

Alkali Carbonate Effects onN-(2-Hydroxyethyl)ureaCyclization: Application to a 2-Imidazolidinone Scale-Up

“…The symmetrical urea 9 (a minor by‐product) precipitated from the reaction mixture and was removed by filtration. The CH 2 Cl 2 filtrate containing the presumed N ‐acyl imidazole 10 was treated with aminol 7 and stirred overnight to afford the desired N ‐(2‐hydroxyethyl)urea 11 , which was isolated by flash chromatography (318 g, 60% overall yield).…”

N-Perfluoroalkylsulfonylimido derivatives of arenecarboxylic acid amides and their oxidative aza Hofmann rearrangement

“…1. The analysis of 19 F NMR spectra of the compounds with rigid C NSO 2 CF 3 and C-NHSO 2 CF 3 groups has confirmed that a signal of the NSO 2 CF 3 group is in the range À78 to À80 ppm, and that of NHSO 2 CF 3 group at À75 to À77 ppm [6,7]. In the 19 F NMR spectra of the compounds 2a-e signals at À79 to À80 ppm are observed, which correspond to structure A in solution.…”

“…1H, w s, NH);19 F NMR ([D 6 ]acetone): d À79.2 (s, 3F, SO 2 CF 3 ), À117.2 (s, 1F, ArF); 13 C { 1 H} NMR (125 MHz, [D 6 ]DMSO): d 159.4 (d, 1 J CF = 241 Hz), 154.7, 134.8, 125.2 (d, 3 J CF = 7.5 Hz), 119.5 (q, 1 J CF = 321 Hz), 115.4 (d, 2 J CF = 22.5 Hz), 65.5, 47.3.…”

“…1 H NMR ([D 6 ]acetone): d 3.56 (4H, t, 2CH 2 ), 3.68 (4H, t, 2CH 2 ), 3.83 (3H, s, OCH 3 ), 6.96-7.20 (4H, dd, ArH), 8.73 (1H, s, NH); 19 F NMR ([D 6 ]acetone): d À79.1 (s, 3F, SO 2 CF 3 ); 13 C { 1 H} NMR (125 MHz, [D 6 ]DMSO): d 156.8, 154.8, 131.1, 124.8, 119.6 (q, 1 J CF = 320 Hz), 114.0, 65.5, 55.1, 47.2.4.6.3. 4-[N-(4-Trifluoromethylphenyl)-N 0 -trifluoromethylsulfonylamidino]morpholine (7d)It was obtained as a 2:1 mixture with the morpholinium salt of trifluoromethanesulfonamide.ArH),8.90 (1H, s, NH);19 F NMR ([D 6 ]acetone): d À80.5 (s, 3F, SO 2 (CF 2 ) 3 CF 3 ), À112.9 (s, 2F, SO 2 (CF 2 ) 3 CF 3 ), À117.0 (s, 1F, ArF), À120.4 (s, 2F, SO 2 (CF 2 ) 3 CF 3 ), À125.4 (s, 2F, SO 2 (CF 2 ) 3 CF 3 );13 C { 1 H} NMR (125 MHz, [D 6 ]DMSO): d 159.3 (d, 1 J CF = 240 Hz), 154.5, 134.8, 125.0 (d, 3 J CF = 9 Hz), 115.5 (d, 2 J CF = 22.5 Hz), 118.0-108.0 (m, C 4 F 9 ), 65.4, 47.2. Anal.…”

Electrophilic Substitution of the Pyrrole Ring

“…Nucleophilic attack by the pyrrole ring upon phenyl isocyanate occurs slowly at room temperature to give a product melting at 153-4°, whereas when the reaction is conducted at 100°, the melting point of the product is 142-3° (402,(448)(449)(450)(451) $ m c e the product of the reaction of pyrrylpotassium with phenyl isocyanate has the higher melting point and is known to be the 1-carboxanilido compound (see Section H), the lower melting point product is undoubtedly the thermodynamically more stable 2-isomer. (375a) Evidence for the rapid initial formation of the kinetic product, the 1-isomer, followed by thermal rearrangement is provided by the observation that 1-methylpyrrole reacts extremely slowly with phenyl isocyanate to give the 2-carboxanilide.…”