Synthesis of Some New Pyrazolopyridines, Pyrazolothienopyridines, Pyrazolopyridothienopyrimidines and Pyrazolopyridothienotriazines

The Reaction of 1‐Phenylpyrazolidine‐3,5‐dione with Active Nitriles Using Phase Transfer Catalysis Conditions Technique

“…The reaction pathway was assumed to proceed through the nucleophilic addition of the formed carbanion at position-4 of compound 1 on the C═C group of the nitrile reagent with elimination of ethanol molecule to give 2a-c. The subsequent step is the addition of the tautomeric OH [14,[16][17][18] to the CN group in all cases forming the corresponding pyranopyrazoles 3a-c.…”

“…Pyranopyrazoles [9], 1,3-thiazines [10], thiazoles [11], thienopyrazoles [12], and furopyrazole [13] represent important classes of heterocycles, which have been developed for different purposes in the pharmaceutical field. In continuation of our previous works, which had dealt with using active nitriles in synthesis of polyfused-and spiropyrazoles [14][15][16][17][18][19][20][21], herein, we report the synthesis of pyrano[2,3-c] pyrazole, thiazole, 1,3-thiazine, 1,3-oxothiinopyrazole, and furo[2,3-c]pyrazole derivatives starting with 1phenylpyrazolidine-3,5-dione [1][2][3][4]10,14].…”

Synthesis of Pyrazolo[3,4‐b]pyridin‐6‐ones

“…In the report [119], potential synthesis of 6‐oxo derivative of pyrazolopyridine ( 253 ) was presented by means of oxidation of the appropriate mercapto derivative ( 250 ). It was also shown that its methylthio derivative ( 251 ) could be oxidized into the acid ( 252 ), the alkaline hydrolysis of which resulted in pyrazolopyridin‐6‐one ( 253 ; Scheme 63).…”

A simple and efficient preparation of pyrazolo[3,4‐b]‐pyridine derivatives through an unexpected reaction of cyanothioacetamide under microwave irradiation

“…[7] 3, 87.7, 107.7, 116.1, 120.5, 123.7, 125.7, 129.1, 130.5, 138.8, 140.7, 143.5, 148.3, 150 1,116.5,120.5,125.6,128.5,128.6,129.0,129.7,134.2,138.9,143.8,151.1,152.6,159.3;MS (ESI): m/z 348 (M + + Na). 14.4, 88.1, 108.0, 116.2, 120.6, 123.7, 124.6, 125.7, 129.1, 130.4, 135.4, 135.7, 138.8, 143.5, 147.7, 149.9, 151.2, 159 88.2, 108.0, 116.4, 120.5, 125.7, 128.7, 129.1, 130.7, 133.0, 134.6, 138.9, 143.7, 151.2, 151.3, 159.3 88.4, 108.0, 115.8, 120.5, 125.7, 127.7, 129.1, 129.7, 130.5, 131.4, 131.6, 133.1, 138.8, 143.5, 149.4, 151.1, 159.3 14.4, 88.0, 107.9, 116.4, 120.6, 123.3, 125.7, 129.1, 130.9, 131.6, 133.4, 138.9, 143.7, 151.2, 151.3, 159.3 13.0, 88.3, 107.9, 115.8, 120.5, 121.3, 125.7, 128.2, 129.1, 130.3, 131.6, 132.7, 135.2, 138.9, 143.5, 151.0, 151.1, 159.3 115.5, 115.7, 116.4, 120.5, 125.6, 129.0, 130.5, 131.1, 131.2, 138.9, 143.7, 151.1, 151.6, 159.3, 161.7, 164 8, 108.2, 115.9, 116.0, 116.1, 120.6, 121.6, 121.7, 124.9, 125.8, 129.1, 131.1, 132.4, 132.5, 138.8, 143.5, 146.1, 151.1, 157.3, 159.2, 159.7 6, 55.4, 88.1, 108.3, 113.9, 116.7, 120.5, 125.6, 126.1, 129.0, 130.3, 139.0, 143.9, 151.2, 152.6, 159.4, 160.3 6,120.5,125.6,128.6,129.0,131.3,139.0,139.3,143.9,151.2,152.8,159.3;MS (ESI): m/z 362 (M + + Na).…”

“…In this field, we have demonstrated that the one-pot reaction of aromatic aldehydes, cyanothioacetamide, and malononitrile under MWI is an efficient way for the synthesis of thiopyran derivatives [5]. Recently, Ghattas et al reported a novel preparation of pyrazolo[3,4-b]-pyridine-thiones from the reaction of arylidene-cyanothioacetamide with 1-phenylpyrazolidine-3,5-dione [6]. Although the preparative procedure reported there is relatively simple, improvements are still needed in terms of the reaction time and operational simplicity because arylidene-cyanothioacetamide needs to be prepared separately from aldehyde and cyanothioacetamide and the reaction needs several hours to complete.…”