phosphate buffer; sodium nitrite in water; N,N-dimethyl-formamide T=85°C; 2 h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

phosphate buffer; sodium nitrite in water; N,N-dimethyl-formamide T=50°C; 2 h; Title compound not separated from byproducts;

Nitrite in acetic acid T=20°C; 12 h; other temperature; other time; other pH; Product distribution;