Base promoted peroxide systems for the efficient synthesis of nitroarenes and benzamides Sampa Gupta a , Alisha Ansari a,b , Koneni V. Sashidhara a,b,⇑ a Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India b Academy of Scientific and Innovative Research, New Delhi 110025, India article info Article history: Received 3 May 2019 Revised 19 August 2019 Accepted 21 August 2019 Available online 22 August 2019 Keywords: Aniline Nitrobenzene Benzyl amine Benzamide Oxidation Base Peroxide abstract A useful and efficient approach for the synthesis of nitroarenes from several aromatic amines (including heterocycles) using peroxide and base has been developed. This oxidative reaction is very easy to handle and afforded the products in good yields. Formation of benzamides from benzylamine was also success- fully carried out with this metal-free catalytic system in good to excellent yields. Ó 2019 Elsevier Ltd. All rights reserved. Introduction Nitro compounds are considered as an ‘ideal intermediates’ for the synthesis of commercially important chemicals like dyes, per- fumes, and pharmaceuticals [1–4]. There are numerous nitro con- taining drugs available in the market such as nitroxoline, oxamniquine, metronidazole, nitrofurantoin, chloramphenicol, and nitrofural (Fig. 1) [5–10]. Due to environmental concerns the preparation of nitro compounds in large scale by classical direct nitration method is not a benign choice as it requires very harsh conditions. Therefore, the direct oxidation of amines into nitro compounds draws the attention of researchers as it is a safer pro- cess than the classical method. Thus, several protocols have been developed for the oxidative transformation of aryl amines to nitroarenes (Fig. 2). Oxidants like H 2 O 2 [11], m-CPBA [12], HOF- CAN [13], TBHP with KI [14], peracetic acid [15], peroxyfluoroacetic acid [16], sodium perborate with tungstophosphoric acid and cetyl-trimethylammonium bromide (CTAB) [17], TBHP with CrS-2 [18], TBHP with Rh 2 (cap) 4 [19], and H 2 O 2 with CaWO 4 [20], were employed for this transformation. However, most of the reported methods suffer from many shortcomings, such as uncontrolled oxidation, use of harsh reaction conditions, poor yields, longer reaction times, and poor selectivity. In addition to this, oxidative method via H 2 O 2 has been previously reported as environmental friendly and cheaper reagent, since its only byproduct is water. Due to the poor oxidizing nature of H 2 O 2 , it needs to be coupled with a catalyst or a reagent to carry out the oxidation by activating it to a reactive intermediate. Therefore, the development of mild and effective protocol is highly desirable in this area. On the other hand, amides are another important chemical class, which are widely used as intermediates in various organic syntheses and also an important linkage in proteins and peptides. They are useful raw material for plastic industry, detergent, https://doi.org/10.1016/j.tetlet.2019.151076 0040-4039/Ó 2019 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Medicinal and Process Chemistry Division, CSIR- Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India. E-mail address: kv_sashidhara@cdri.res.in (K.V. Sashidhara). Fig. 1. Representative nitro containing biologically active molecules. Tetrahedron Letters 60 (2019) 151076 Contents lists available at ScienceDirect Tetrahedron Letters journal homepage: www.elsevier.com/locate/tetlet