An evaluation of credentials of a multicomponent reaction for the synthesis of isothioureas through the use of a holistic CHEM21 green metrics toolkit

Multicomponent reactions (MCRs) are considered green and material efficient methods for the synthesis of organic compounds, however very few studies have investigated the metrics of the upstream processes involved to achieve the starting materials used in these reactions. A novel MCR-approach for the synthesis of N-cyclohexyl-S-methyl-N′-phenylisothiourea from S-methyl methanethiosulfonate, cyclohexyl isocyanide and aniline was appraised in terms of its green metrics using the CHEM21 green metrics toolkit and compared with those of the state of the art approach. The upstream process leading to the component starting materials for both approaches were also appraised to gain an insight into how the greenness of both methods translate from the raw materials to the final product.