Synthesis of a new series of pyrazolo[1,5‐a]pyrimidines structurally related to zaleplon

Abstract

The reaction between 3-(dimethylamino)/3,3-bis(methylthio)-1-(substituted)prop-2-en-1-ones and 4-substituted-5-amino-1H-pyrazoles afforded new pyrazole[1,5-a]pyrimidines structurally related to Zaleplon. The chemical modifications introduced at the 3-, 5-, and 7-positions of the bicyclic structure revealed new promising candidates for the treatment of sleep disorders.

Solubility Study of (2E)-1-(3-Pyridyl)-3-(dimethylamino)-2-propen-1-one in Different Pure Solvents and Binary Solvent Mixtures from 278.15 to 328.15 K

“…The DSC thermogram of (2 E )-1-(3-pyridyl)-3-(dimethylamino)-2-propen-1-one is shown in Figure . We can observe from the picture that a sharp peak appears at the fusion temperature ( T fus ) of 387.65 K. This is the same as the melting point reported in the literature . The value of fusion enthalpy (Δ H fus ) is 17.4 kJ·mol –1 by calculation.…”

Pyridine-Based Heterocycles. Synthesis of New Pyrido [4',3':4,5]thieno[2,3-d]pyrimidines and Related Heterocycles

“…In view of the above findings and in continuation to our interest in the synthesis of polyfused heterocycles of biological importance [10,11,12,13,14,15,16,17,18,19,20,21,22,23], the synthesis of the title compounds was deemed of interest. Thus when the thienopyridine aminoester 1 , which is easily accessible via the Gewald reaction between 1-methylpiperidin-4-one, elemental sulfur and ethylcyanoacetate [7], was reacted with triethyl orthoformate, the corresponding ethoxymethyleneamino intermediate 2 was obtained as a reddish brown oil.…”

A facile environment-friendly one-pot two-step regioselective synthetic strategy for 3,7-diarylpyrazolo[1,5-a]pyrimidines related to zaleplon and 3,6-diarylpyrazolo[1,5-a]pyrimidine-7-amines assisted by KHSO $$_{4}$$ 4 in aqueous media

“…The drug zaleplon [16][17][18] has been found to be efficient in the treatment of sleep disorders where difficulty in falling asleep is the primary issue. Zaleplon is known to selectively bind to the α1-containing GABA A receptors which help produce the primary therapeutic hypnotic properties [16,19]. Prompted by the pharmaceutical importance of pyrazolo [1, 5-a]pyrimidine derivatives, synthetic chemists have devoted serious efforts to the synthesis of pyrazolo [1,5-a]pyrimidines.…”

“…For example, pyrazolo [1,5-a]pyrimidine derivatives have been prepared by reacting substituted 3(5)-aminopyrazoles with enaminones [11,18,19], enaminonitriles [20], β-ketoaldehydes [21], β-ketoesters [22], 1,3-diketones [23,24], sodium salts of formyl ketones [25], acetoacetanilides [26] and 3-oxo-2-phenylpropanenitrile [27] under acidic conditions (i.e., acetic acid, conc. HCl).…”