Nitric Acid → 6-Nitrobenzo[d]thiazole-2-carbonitrile

Participants

Reaction Steps

In particular 2-cyano-benzothiazole 10 (0.84 mmol, 0.134 g) was suspended in 0.563 ml conc. H2SO4 at 0° C. 1.3 equivalents of concentrated HNO3 (1.1 mmol, 0.069 g) was added portionwise over 10 min to the stirring solution; not to exceed 0° C. over a total of ˜45 min. The reaction proceeded further for 2 h and at 5 h the product was evident. The reaction was then poured over ice/water, extracted into EtOAc, and concentrated in vacuo to yield a crude yellow residue 11. For analytical characterization, a small portion was purified by semi-preparative HPLC at 10 mL/min on a Waters preparative machine (Waters Symmetry prep C18, 7 μm, 19×300 mm column, photodiode array detection) with a linear gradient from 90% H2O (0.1% TFA) to 50% MeCN (0.1% TFA) for 30 min yielding a large product peak at ˜27 minutes. The fractions were collected and lyophilized using Kinetics Flexi-Dry freeze-dryer.

Provenance & Evidence