The treatment of pyrrolomethane 1 with acetyl chloride and boron trifluoride etherate in the presence of triethylamine gave 4,4-Difluoro-3,5,8- trimethyl-4-bora-3a,4a-diaza-s-indacene 2a.
When benzoylchloride and chloroacetyl chloride were used instead of acetyl chloride, corresponding 4,4- Difluoro-8-phenyl-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene 2b and 4,4-difluoro-8-chloromethyl-3,5- dimethyl-4-bora-3a,4a-diaza-s-indacene 2c were formed, respectively.
Disubstituted compounds were obtained from the reactions of 4 with methyl iodide, benzyl chloride,
acetyl chloride, benzoyl chloride, 4-methoxybenzoyl chloride, 2-chlorobenzoyl chloride and propanoyl chloride in acetone in the presence of K2CO3 via replacement of all the oxime protons with alkyl and acyl groups.
