Abstract
New starting material, ethyl 6-amino-1,3-dimethy1-2,4-dioxo-1,2,3,4tetrahydrothieno[3,2-d]pyrimidine-7-carboxylate (2) was prepared by Gewald reaction using N,N-dimethylbarbituric acid. The reaction of compound 2 with phenyl isothiocyanate yields the non-isolable intermediate 3, which gave thiocarbamoyl derivative 4 upon treatment with dilute HC1. Also compound 2 react with carbon disulfide afforded carbamodithioic acid derivative 5, followed by addition of aniline to give the same product 4. On the other hand, when compound 4 refluxed in DMF and TEA afforded the thieno[2,3-d:4,5-d']dipyrimidine derivative 6. Moreover, treatment of 3 with alpha-halo compounds in basic medium afforded the corresponding thiazol-2-ylidene derivatives (8a, 8b, 10), thiazolidin-2-ylidene derivative 12 and 1,3-thiazinan-2-ylidene derivative 15, respectively. Furthermore, the reaction of 2 with malononitrile and 2-cyano-3-phenylacrylamide afforded the corresponding pyrido[31,21:4,5]thieno[3,2-d]pyrimidine derivatives 16 and 17, respectively. All the newly synthesized compounds were characterized by IR, H-1-NMR, C-13-NMR, mass spectra and elemental analyses.