112085-24-2

Upstream product

• 73798-89-7 phenacyl hydrazinodithioformate 
• 5316-81-4 3-amino-4-phenylthiazoline-2(3H)-thione 
• 532-27-4 1-chloroacetophenone 
• 112085-29-7 2-(3-Amino-4-phenyl-3H-thiazol-2-ylidene)-malononitrile 

Relevant academic research and scientific papers

Amino-thienopyrazoles and Amino-thienopyrroles

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.

FUSED THIAZOLES FROM 3-AMINO-THIAZOLINE-2-THIONES: SYNTHESIS OF PYRAZOLOTHIAZOLE AND THIAZOLO-1,3,4-THIADIAZINE DERIVATIVES

Two approaches for the preparation of a number of pyrazolothiazoles are reported.The first involves reaction of 3-amino-4-phenyl-thiazoline-2-thione 1 with phenacyl bromides to give thiazolo-1,3,4-thiadiazines 2 which by action of triethylamine are converted into the pyrazolothiazoles 4.The second is based on the reaction of 3-amino-2-methylthio-4-phenylthiazolium cation 5 with activated acetonitriles to give 7-substituted 6-amino-3-phenylpyrazolothiazoles 7.