Nederlof, A. published the artcileChemistry of rhodanine and its derivatives. Preliminary communication, Product Details of C7H6N2O2S, the publication is Recueil des Travaux Chimiques des Pays-Bas (1962), 578-80, database is CAplus.
Impure 5-(2,4-dinitrobenzylidne)-3-ethylrhodanine, m. 133°, was prepared by condensing 3-ethylrhodanine with 2,4-dinitrobenzaldehyde. Refluxing the impure product with EtOAc gave the more pure compound and presumably I (R = Et), m. 252-2.5°. The addition of large quantities of p-MeC6H4SO2Cl accelerated the formation of orange I (R = Et), as well as of I (R = CH2CH:CH2), m. 190.5-1°, and I (R = CH2CO2Et), m. 183-4°. These compounds reduced to readily autoxidized II (R = Et), light yellow, m. 155-7°, II (R = CH2CH:CH2), yellow, m. 121.5-3.5°, and II (R = CH2CO2Et), nearly colorless, m. 169-70°, resp. The “anil method” of rhodanine condensation gave purer compounds with higher yields. 3-Aminorhodanine reacted in boiling EtOH with p-nitrobenzaldehyde to give orange 3-amino-5-(p-nitrobenzylidene)rhodanine, m. 230-1°, not the yellow 3-(p-nitrobenzylidenamino)rhodanine as reported by Ueda and Ohta (CA 52, 401d).
Recueil des Travaux Chimiques des Pays-Bas published new progress about 7668-28-2. 7668-28-2 belongs to isothiazole, auxiliary class Sulfamide,Amine,Benzothiazole, name is 3-Aminobenzo[d]isothiazole 1,1-dioxide, and the molecular formula is C7H6N2O2S, Product Details of C7H6N2O2S.
Referemce:
https://en.wikipedia.org/wiki/Isothiazole,
Isothiazole – ScienceDirect.com