Development and assessment of green synthesis of hydrazides

Enhancing the efficiency and maneuverability of organic synthesis constitutes one of the most exciting challenges to synthetic chemists. Within the last decade, green chemistry has attained the status of a major scientific discipline. The investigation and application of green chemistry principles has led to the development of cleaner and more benign chemical processes, with many new technologies being developed each year. In today’s world, synthetic chemists in both academia and industry are constantly challenged to consider more environmentally benign and sustainable methods for the generation of desired target molecules. Among the twelve principles of green chemistry “design for energy efficiency” is one of the key principles of relevance to synthetic chemists. Much attention has been given to the applications of microwave dielectric heating in organic synthesis since the first reported acceleration of a chemical reaction under the influence of microwaves. It is significantly more energy-efficient than conventional heating with the enhanced reaction rates, simplified manipulation and work-up, and higher purity of final products. Hydrazides are important intermediates in organic synthesis, especially in the preparation of pharmaceuticals and agrochemicals. Their synthesis has attracted significant attention due to their utility as building blocks in many syntheses, e.g., 1,2,4-triazoles, 1,3,4-oxadiazoles, 1,3,4-thiadiazoles, 1,2,4,5tetrazines etc. Hydrazides are also potent bioactive molecules and possess biological activities such as antituberculous agents (Isoniazid), HIV inhibitors, inhibitors of myeloperoxidase, glycogen phosphorylase, pesticides. Maleic hydrazide is an important herbicide. 5-Substituted-1,3,4-oxadiazoles-2-thiols 1 are potential nitrification inhibitors under development. We were in need of an efficient, fast and high yielding method for preparing hydrazides, intermediate to compound 1, to fulfill its bulk requirement.