Synthesis and S‐methylation of 2‐thioxopyrido[3′,2′:4,5]thieno[3,2‐d]‐pyrimidin‐4(3H)‐ones with and without a phase transfer catalyst

Abstract

A number of 2‐thioxopyrido[3′,2′:4,5]thieno[3,2‐H]pyrimdin‐4(3H‐ones (5) have been synthesized by cyclocondensation of 2‐carbethoxy‐3‐amino‐4‐phenyl‐6‐substituted‐thieno[2,3‐b]pyridines (3) with various isothiocyanates. Compounds 5 were S‐methylated routinely and the reactions compared under solid‐liquid phase transfer conditions to obtain 2‐methylthiopyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidin‐4(3H)‐ones (6). The new triheterocyclic pyridothienopyrimidines were prepared with the objective to study their pharmacological properties.

Novel Selective 5-HT3 Receptor Ligands: Facile Generation Methods for 2-Amino- and 4-Aminopyrido[4’,3’:4,5]thieno[2,3-d]pyrimidines

“…The precipitated product was filtered off, washed with water, dried, and crystallized from ethanol as pale yellow crystals. Yield 82%, m. p. > 300 • C -IR (KBr):ν = 3380 -3285 (NH 2 -5,6,7,8-tetrahydropyrido[4',3':4,5]thieno [2,3-d] [1,3]thiazine-7-carboxylate (6) A suspension of compound 5 (6.0 g, 13 mmol) in 98% sulfuric acid (60 ml) and few drops of water was stirred at 40 -50 • C for 10 h. The resultant clear solution was slowly poured on ice-water and sodium bicarbonate (300 ml). The precipitate was collected, washed with ethanol and dried to give compound 6.…”

“…The serotonin neurotransmitter is involved in a number of different physiological functions through its interaction with 14 types of receptors [10]. These are G-protein-coupled receptors, with the exception of the 5-HT 3 , which is a ligand gated-ion channel receptor. 5-HT 3 receptor antagonists, such as ondansetron, granisetron, or tropisetron [11] are used as anti-emetic drugs to prevent vomiting associated with chemotherapy or radiation-induced emesis, but literature studies [12] indicated that they could possess numerous other potential therapeutic applications in the control of pain or in the treatment of psychosis, memory impairment, depression, anxiety, schizophrenia, and drugs abuse.…”

Synthesis and interconversion of isomeric pyrrolotriazolopyrimidines

“…Few works have been found in which a triazole ring was annellated onto existing pyrrolo [2,3-d]pyrimidines [23][24][25]. Therefore, in continuation of our interest in fused triheterocyclic pyrimidines [26][27][28][29], it was interesting to report the synthesis of 7H-pyrrolo[3,2-e] [1,2,4]triazolo [1,5- …”

Synthesis and Interconversion of Isomeric Pyrrolotriazolopyrimidines.

“…So far, there has not been any report on isomeric conversion in the pyrrolotriazolopyrimidine system. Therefore, in continuation of our interest in fused triheterocyclic pyrimidines [26][27][28][29], it was interesting to report the synthesis of 7H-pyrrolo [3,2- Therefore, in continuation of our interest in fused triheterocyclic pyrimidines [26][27][28][29], it was interesting to report the synthesis of 7H-pyrrolo [3,2- …”