B. With NaOH. (N-Benzoyl-N-methyl)-2-methyltelluroaniline (7). A suspension of compound 2
(0.90 g, 2 mmol) in 1N aqueous NaOH (100 ml) was stirred for 1 h at 80-90°C. After cooling the reaction mass
the orange precipitate of ditelluride 5 was filtered off, dried, and suspended in methanol (20 ml) without further
purification. Dry sodium borohydride was added in small portions to the stirred suspension under argon until the
precipitate had completely dissolved to give a colorless solution. Dimethyl sulfate (0.5 g, 4 mmol) was added
rapidly to the colorless solution, the reaction mixture was stirred for 40 min with mild heating, cooled, poured
into water (100 ml), and extracted with chloroform (3×15 ml). The extract was dried over Na2SO4 and the
1
solvent evaporated to give a colorless crystalline product 7 (0.46 g, 65%), mp 145-147° (2-propanol). H NMR
spectrum (CDCl3), δ, ppm: 6.75-7.57 (9H, m, Harom); 3.30 (3H, s, NCH3); 2.08 (3H, s, TeCH3). Found, %:
C 50.91; H 4.07. C15H15NOTe. Calculated, %: C 51.04; H 4.29.
C. With NH2NH2·H2O. Di(2-N-methylaminophenyl)ditelluride (8). A suspension of compound 2
(2.25 g, 5 mmol) in hydrazine hydrate (10 ml) was stirred while boiling for 10 min. The red pasty mass was
separated by decanting the boiling liquid phase of the reaction mixture, dried and crystallized from 2-propanol to
1
give claret-red crystals of ditelluride 8 (0.6 g, 51%), mp 100-102°C. H NMR spectrum (CDCl3), δ, ppm:
6.30-7.80 (4H, m, Harom); 4.25 (1H, s, NH); 2.65 (3H, s, NCH3). Found, %: C 36.52; H 3.61. C14H16N2Te2.
Calculated, %: C 35.96; H 3.46.
The orange-yellow precipitate which formed on cooling the decanted liquid phase was filtered off, dried,
and recrystallized from ethanol to give orange-yellow crystals of compound 9 (0.28 g, 48%), mp 190-191°C (mp
191-192°C [5]).
D. With 1,2-(H2N)2C6H4. Compound 8. Compound 2 (2.25 g, 5 mmol) and o-phenylenediamine (0.55g,
5 mmol) were stirred in DMF (50 ml) with mild boiling for 3 h. The claret-red reaction mixture was cooled and
the unreacted salt 2 was filtered off. From the filtrate some of the solvent (40 ml) was evaporated under reduced
pressure, the residue was poured into water and extracted with benzene (2×20 ml). The extract was dried over
Na2SO4, the solvent was evaporated, and the residue was chromatographed on an Al2O3 column (eluent
chloroform). Fine shining claret-red crystals of compound 8 were obtained (0.51 g, 43%), mp 100-102°C
(2-propanol). The yellow residue which was not extracted by benzene was filtered off, dried, and recrystallized
from benzene to give fine colorless crystals of 2-phenylbenzimidazole 10 (0.38 g, 39%), mp 292-293°C (mp
294°C [6]).
Reactions of 1-Methyl-2-phenylbenzotelluronioazole Perchlorate (3). With NaOH.
2-Phenylbenzotellurazole (1). A suspension of salt 3 (0.42 g, 1 mmol) in 1 N alcoholic NaOH (50 ml) was
stirred with reflux for 1 h. The solution obtained was cooled, poured into water (100 ml), and extracted with
chloroform (3×15 ml). The extract was evaporated and the residue washed with hexane to give compound 1
(0.214 g, 70%) as large yellow crystals, mp 102-103°C (mp 102-103°C [10]).
With Phenol. 2-Phenylbenzotellurazolium Perchlorate (12). Phenol (0.21 g, 2 mmol) in acetonitrile
(10 ml) was added to a solution of salt 3 (0.84 g, 2 mmol) in acetonitrile (10 ml) and the reaction mixture was
boiled with stirring for 2 h. The solvent was partially evaporated and ether (20 ml) was added to the reaction
mixture. The precipitate formed was filtered off and dried to give product 12 as fine yellow crystals (0.69 g,
85%), mp 180-182°C (dec.). Found, %: C 38.70; H 2.30. C13H10ClNO4Te. Calculated, %: C 38.30; H 2.48.
The product 12 was identical to a sample of 12 prepared by the reaction of 2-phenylbenzotellurazole (1)
with perchloric acid in ethanol (no depression of the melting point in a mixed determination).
With Et3N. Methyltriethylammonium Perchlorate (13). Triethylamine (0.3 g, 3 mmol) was added
stepwise to a solution of salt 3 (0.84 g, 2 mmol) in acetonitrile (20 ml), the reaction mixture was stirred while
boiling for 1 h and then some solvent (10 ml) was evaporated. Ether (20 ml) was added to the remaining cooled
solution, the colorless precipitate was filtered off and recrystallized from ethanol to give fine colorless crystals of
1
the perchlorate 13 (0.321 g, 75%), mp 200-202°C. H NMR spectrum (DMSO-d6), δ, ppm: 3.55 (6H, q,
CH3CH2); 3.20 (3H, s, NCH3); 1.50 (9H, t, CH3CH2). Found, %: C 38.40; H 8.42. C7H18ClNO4. Calculated, %:
C 39.0; H 8.42. The solvent was evaporated from the filtrate and the residue recrystallized from hexane to give
large yellow crystals of compound 1 (0.445 g, 73%), mp 101-102°C.
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