Synthesis of 4‐ and 5‐(s‐triazolo[4,3‐b]pyridazinyl‐3)‐substituted cyclic polyols

Abstract

4(R)‐(6‐Chloro‐s‐triazolo[4,3‐b]pyridazinyl‐3)‐1,4‐furanoses 10 and 11, 5(R)‐(6‐chloro‐s‐triazolo[4,3‐b]pyridazinyl‐3)‐1,5‐pyranose 13, and 2(S),3(R)‐dihydro‐5‐(6‐chloro‐s‐triazolo[4,3‐b]pyridazinyl‐3)‐2,3‐O‐isopropylidenefuran (12) were prepared by cyclization of hydrazones 6–9 obtained from 6‐chloro‐3‐hydrazinopyridazine (1) and aldofuranoses 2, 3 and 4, and aldopyranose 5.

Synthesis, Docking Studies and Anticancer Activity of New Substituted Pyrimidine and Triazolopyrimidine Glycosides

“…Formation of the triazolopyrimidine with this mode of cyclization was also confirmed by formation of cyclized product 12 by reaction of substituted pyrimidine 4 with bromine in acetic acid which is the same product of alkylation of triazolopyrimidine 10 with 2-chloro-1,1-dimethoxyethane. These results are in accordance with previously reported results for similar triazolpyrimine syntheses (Shaban et al, 1995;Turk et al, 1998) and also with their mode of preparation. The prepared triazolopyrimidine 10 was also used, like the substituted pyrimidine 3, to prepare another N-substituted triazolopyrimidine derivative of the triazolopyrimidne system by reaction with oxygenated hydroxyl alkyl; namely 2-(2-chloroethoxy)ethan-1-ol and gave the N-substituted derivative 11, in 77% yield.…”

Formal Total Synthesis of Manzacidin C Based on Asymmetric 1,3-Dipolar Cycloaddition of Azomethine Imines

“…With optimized conditions for the asymmetric 1,3-dipolar addition of azomethine imines to methallyl alcohol in hand, we turned our attention to the total synthesis of manzacidin C. One of the major challenges in synthesizing manzacidin C is the removal of the three-carbon bridge on the pyrazolidine ring. Although many asymmetric 1,3-dipolar cycloadditions of azomethine imines possessing pyrazolidinone moieties to olefins have been reported, the conversion of the produced fused pyrazolidines to acyclic 1,3-diamine derivatives has not yet been achieved, to the best of our knowledge . We envisaged that retro-Michael addition of the amino group from the propanamide moiety of the pyrazolidinone ring could proceed before or after cleavage of the N–N bond.…”

Synthesis of heteroaryl substituted α‐amino acid derivatives, polyols, and related compounds

“…In the case of the unsaturated aldehyde 91, the oxidation step had to be performed with lead tetraacetate. In this manner, the corresponding cyclic 1,2,4-triazolo[4,3-b]pyridazinyl substituted polyols 92-97 were obtained in 44-76% yields [46,47] (Scheme 18).…”