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N-Polyheterocycles
Published in Navjeet Kaur, Metals and Non-Metals, 2020
The synthesis of pazopanib begins with an indazole which is produced by diazotization and spontaneous cyclization of 2-ethyl-5-nitroaniline in the presence of tert-butyl nitrite. This indazole is methylated with complete regioselectivity using either Meerwein’s salt, dimethyl sulfate or trimethyl-o-formate. A tin-assisted reduction of the nitro group unmasks the aniline which undergoes nucleophilic aromatic substitution to introduce the pyrimidine into the synthesis of pyrimidoindazole. The secondary amine function is then methylated with methyl iodide prior to a second SNAr reaction with sulfonamide derived aniline to provide pazopanib (Scheme 52) [118–120].
Greener Synthesis of Potential Drugs
Published in Ahindra Nag, Greener Synthesis of Organic Compounds, Drugs and Natural Products, 2022
Renata Studzińska, Renata Kołodziejska, Daria Kupczyk
A green, metal-free synthesis of isatin oximes via radical coupling reactions of oxindoles with t-BuONO (tert-butyl nitrite) occurs in water. Reactions were carried out at room temperature. Using this method, 15 oximes of isatin were obtained which differed in substituents at the 5-position of the oxindoles system and substituents at the nitrogen atom, with good yields (up to 97%). Unfortunately, the substrate N,2-diphenylacetamide was not suitable for the radical coupling reaction under the current conditions [42].
Practical and efficient recyclable oxidative system for the preparation of symmetrical disulfides under aerobic conditions
Published in Journal of Sulfur Chemistry, 2021
Chiu Ling Ong, Thorsten Heidelberg, Joon Ching Juan, Nader Ghaffari Khaligh
Tert-butyl nitrite (TBN) with oxygen was also used to preparation of symmetrical disulfides [44]. The use of pure oxygen, generation of NOX as by-products, higher temperature, and lower yields within longer reaction times are the disadvantages of this methodology in comparison with the current protocol.