170953-52-3Relevant academic research and scientific papers
Amino-thienopyrazoles and Amino-thienopyrroles
Gewald, K.,Rennert, S.,Schindler, R.,Schaefer, H.
, p. 472 - 477 (2007/10/02)
The synthesis of thienopyrazoles and thienopyrroles is described.From the dithioliumsalt (1) and potassium hydroxide the potassium-(2,2-dicyan-1-methylthioethen-1-yl)-thiolate (2) is formed.This reacts with hydrazine hydrate to form the 3-amino-5-thioxo-pyrazol-4-carbonitrile (3).S-alkylation with α-chlorocarbonyl compounds yielding (6a-c) leads via Thorpe-Ziegler-cyclization to 3,4-diaminothienopyrazoles (9) if the position 1 is alkylated (8).Acetyl acetone yields 2-mercapto-pyrazolopyrimidine (5).After S-alkylation (10a-d) are immediately cyclized to thieno pyrazolopyrimidine (11a-d).The ketone (6a) can be cyclized to the pyrazolo thiazole (12). 3 reacts with oxalyl chloride to form the 2,3-dioxo-6-thioxo-imidazopyrazole (13) of which S-phenacyl derivative (14) because the NH-proton cannot be cyclized.The 5-amino-3,4-dicyano-pyrrol-2-thiolate (16) shows the analogous behaviour.The S-alkylation is followed by cyclization, and 3,5-diamino-thienopyrroles (18a-b) arise.Reaction of 5-amino-2-alkylthio-pyrrol-3,5-dicarbonitrile (17) with acetyl acetone provides pyrrolopyrimidine (20a-c) which can be cyclized to form thienopyrimidines (21a-c) very easily.
