Synthesis of thienopyrimidotriazines, a new fused heterocyclic ring system

ABSTRACT

Benzothieno [2, 3 4', 5'] pyrimido [2, l-c] [1, 2, 4] triazines 2, 4 and 6 which represent a new fused heterocyclic ring system were synthesized by reacting 2-hydrazino-5, 6, 7, 8-tertrahydrobenzothieno [2, 3-d]-pyrimidin-4 [3H]-one [1] with phenacyl bromide, bromomalononitrile or chloroacetyl chloride, respectively. Condensation of 6 with aromatic aldehydes produced arylmethylene derivatives 7a, b. Reaction of 1 with phthalic anhydride afforded the phthalazine derivative 8. Also, compound 1 reacted with beta- diketones and with ethyl acetoacetate to produce the pyrazolyl 9a-c and pyrazolinone derivatives 11, respectively. Compound 11 condensed with aromatic aldehydes and coupled with diazotized aromatic amines to afford the corresponding arylmethylene and arylazo derivatives 12 and 13, respectively. All compounds were confirmed by IR, HNMR and analytical data