Patent ID: 7067676

Claim:
A method for the preparation of indole derivatives of the formula wherein X is methyl; R 1 and R 2 are independently hydrogen, halogen, cyano, nitro, hydroxy, optionally substituted alkyl, alkoxy, aralkoxy, carboxy, alkoxycarbonyl, aryl or heteroaryl; or R 1 and R 2 combined together with the carbon atoms to which they are attached form a fused 6-membered aromatic ring; R 3 is hydrogen, cyano, nitro, hydroxyl, optionally substituted alkyl, alkoxy, aralkoxy, carboxy, alkoxycarbonyl, aryl or heteroaryl; and R 4 is hydrogen, halogen, cyano, nitro, hydroxy, optionally substituted alkoxy, aralkoxy, carboxy, alkoxycarbonyl, aryl, or heteroaryl; which method comprises reacting indoles of the formula wherein R 1 , R 2 , R 3 and R 4 have meanings as defined for formula I; with dimethyl carbonate in the presence of a catalytic amount of a base at an ambient temperature.