1: methylene blue With sodium dithionite in water 0.75 h; Inert atmosphere; 2: With sodium hydroxide in water T=18 - 20°C; 1 h; Inert atmosphere; 3: benzoyl chloride in water 22 h; Inert atmosphere;
Ayyangar, N. R.; Khanna, I. K.
Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry, 1981 , vol. 20, # 9 p. 763 - 766