SYNTHESIS AND NEUROTROPIC ACTIVITY OF PYRROLO(2,3-c)PYRAN(THIOPYRAN, PYRIDINE) AND PYRANO(THIOPYRANO, PYRIDO)(4,3:4,5)PYRROLO- (1,2-b)asym-TRIAZINE DERIVATIVES

Abstract

In continuation of our previous investigations devoted to the synthesis of condensed pyrroles [1 – 3], we have developed a method for the synthesis of pyrrolo[2,3-c]pyran(thiopyran, pyridine) derivatives proceeding from 2,2-dimethyl-4-tetrahydropyranylidenemalonic acid dinitrile (Ia) and its thiopyran and pyridine analogs (Ib and Ic, respectively) [4]. The interaction of compounds Ia – Ic with substituted phenyl(furyl)diazomethylketones led to derivatives of pyrrolo[2,3-c]pyran(thiopyran, pyridine) derivatives (IIa – IIi). By treating compounds IIa – IIi with an ethanol solution of potassium hydroxide, we obtained a series of derivatives representing a new heterocyclic system: pyrano(thiopyrano, pyrido)[4 ,3 :4, 5]pyrrolo[1,2-b]asym-triazines (IIIa – IIIi). A special method developed for the synthesis of compounds IIIa – IIIi is based on the reactions of compounds Ia – Ic with diazomethyl ketones on heating to 70°C. Using this procedure, compounds IIIa – IIIi are obtained without isolating intermediate pyrroles IIa – IIi. I: X = O (a), S (b), N-CH3 (c); I, III: X = O, R = C6H5 (a); X = O, R = o-C6H4Cl (b); X = O, R = p-C6H4Cl (c); X = O, R = p-C6H4NO2 (d); X = O, R = p-C6H4CH3 (e); X = O, R = m-C6H4NO2 (f); X = O, R = (g), X = S, R = C6H5 (h);