ethyl N-cyanobenzenecarboximidate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1.89 g of ethyl N-cyanobenzimidate was dissolved in 5 ml of dimethylformamide, and 2.15 g of 6-cyano-3,4-dihydro-2,2-dimethyl-trans-4-amino-2H-benzo[b]pyran-3-ol was added thereto. The mixture was reacted at a temperature of from 100° to 120° C. for 2 hours. The reaction mixture was cooled, then dissolved in 100 ml of ethyl acetate, washed four times with a saturated sodium chloride aqueous solution and then dried over anhydrous sodium sulfate. Then, ethyl acetate was distilled off under reduced pressure. The residual oily substance was purified by silica gel column chromatography to obtain 1.32 g of the above identified compound in the form of crystals. The mixture was reacted at a temperature of from 100° to 120° C. for 2 hours The reaction mixture was cooled washed four times with a saturated sodium chloride aqueous solution dried over anhydrous sodium sulfate Then, ethyl acetate was distilled off under reduced pressure The residual oily substance was purified by silica gel column chromatography to obtain 1.32 g of the

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Following the method of Huffmann and Schaefer (J. Org. Chem. 1963, 28, 1816), a stirred mixture of 50 ml (221 mmol) triethylorthobenzoate, 9.3 g (221 mmol) cyanamide and 42 ml (442 mmol) acetic anhydride was heated at 130-150° C. for 1.5 hours with concomitant removal of the ensuing ethyl acetate and acetic anhydride by distillation from the reaction flask. The reaction mixture was then concentrated in vacuo using a rotary evaporater. Kugelrohr distillation (120° C., 3 mbar) afforded 35.8 g (93%) N-cyano-benzenecarboximidic acid ethyl ester as a colourless oil. ES-MS m/e (%): 175 (M+H+, 100). The reaction mixture was then concentrated in vacuo Kugelrohr distillation (120° C., 3 mbar)