Sanaa M. Eldin

REACTIONS WITH CYANOTHIOACETAMIDE DERIVATIVES: SYNTHESIS AND REACTIONS OF SOME PYRAZOLO[3,4-b]PYRIDINE DERIVATIVES

Abstract The ylidene derivatives of cyanothioacetamide 1a–d reacted with ethyl acetoacetate to give the pyridinethiol derivatives 2a–d. Compounds 2a–d were used as starting material for the synthesis of several heterocyclic compounds. Reactions with hydrazine hydrate, ethyl iodide, methyl chloroacetate and α-chloro ethyl acetoacetate gave the pyridine and annelated pyridine derivatives 5a–d, 6a–d, 7a, 8b–d, and 12a–d, respectively. Compounds 7a, 8b–d and 12a–d reacted with hydrazine hydrate to yield the annelated pyridines 10a–d and 15a–d, respectively.

Reactions and characterization of pyridin-6-one-2-thione and 3-diazotized amino-4-hydroxypyrazolo-[3,4-b]pyridin-6-one

Several pyrido[2,1-b]thiazines and thiazolo[2,3-a]pyridines were synthesized by reactions of cinnamonitriles with appropriate halocarbonyl compounds. Hydrazones of 3-diazotized aminopyrazolo[3,4-b]pyridinones were synthesized by coupling of their corresponding diazonium salts with several active methylene reagents. The obtained hydrazones were cyclized in refluxing ethanol containing a catalytic amount of triethylamine to afford the corresponding pyrazolopyridotriazines. All structures were established by considering the data of elemental analyses, IR, 1H-NMR, and mass spectra.

REACTIONS WITH CYANOTHIOACETAMIDE DERIVATIVES: SYNTHESIS AND REACTIONS OF SOME PYRIDINES AND THIENO[2,3-b]PYRIDINE DERIVATIVES

Abstract The styrlpyridinethione 1a–c reacted with several halogenated compounds; ω-bromoacetophenone, methyl chloroacetate, α-chloroacetylacetone and ethyl-α-chloroacetoacetate to give the corresponding thieno[2,3-b]pyridines 3a–c, 11a–c and the thiazolo[3,2-α]pyridines 14a–c.

Cyanothioacetamide in Heterocyclic Chemistry: Synthesis of Thiopyran, Pyridinethione, Thienopyridine, Pyridothienotriazine and Pyridothienopyrimidine Derivatives

Abstract Cyanothioacetamide (1) reacted with α- and β-naphthaldehyde 2a,b to afford the corresponding 3-naphthyl-2-thiocarboxamidopropenonitriles 3a,b. Compounds 3a,b structures could be elucidated via their reactions with acrylonitrile, ethyl acrylate (4a,b). N-arylmaleimides 6a-c and ethyl acetoacetate (8). The isolated products could be represented as the thiopyran, thiopyranopyrrolidine and pyridinethione derivatives 5a-d, 7a-f and 9a,b respectively. Pyridinethiones 9a,b had been used as the starting materials in the present study in addition to the next ones to synthesize several new thienopyridines, pyridothienotriazine and pyridothienopyrimidines 12a-f, 15a,b, 16b, 17–19a,b respectively through their reactions with the corresponding reagents. All structures of the newly synthesized heterocyclic compounds were established on the basis of the data of IR, 1H NMR and elemental analyses.

Reactions of Cyanothioacetamide: Synthesis of Several New Thioxohydro-pyridine-3-carbonitrile and Thieno[2,3-b]pyridine Derivatives

Cyanothioacetamide (f 1) reacted with α,β -unsaturated carbonyl compounds 2a–d to afford thioxohydropyridine-3-carbonitriles 5a–d, which were used as the starting materials for the preparation of several thienopyridines via their reactions with active halogen-containing compounds, e.g., 2-bromo-1-phenylethanone (7a), 2-bromo-1-p-tolyl-ethanone (7b), chloroacetone (10a), α -chloroacetylacetone (10b), and chloroacetic acid ethyl ester (13). The structure of the newly synthesized heterocyclic compounds were established based on the data of elemental analyses, IR, 1 H NMR, and mass spectra.

REACTIONS WITH CYANOTHIOACETAMIDE AND ITS DERIVATIVES : SYNTHESIS AND CHARACTERIZATION OF SEVERAL NEW PYRIDINE AND ANNELATED PYRIDINE DERIVATIVES

Abstract Several new pyridines and annelated pyridines were synthesised via the reactions of some pyridinethiones with a variety of activated halogenomethyl containing reagents and hydrazines. Structures were established on the basis of elemental analysis and spectral data.

REACTIONS WITH CYANOTHIOACETAMIDE AND ITS DERIVATIVES : SYNTHESIS AND REACTIONS OF SEVERAL NEW THIENO- AND AZOLOPYRIDINE DERIVATIVES

Abstract Several new thieno- and azolopyridine derivatives were synthesized via a new route by reaction of some new di- and tetrahydropyridine thiones with different halogeno-ketones and halogeno-esters. Structures were elucidated by elemental analysis and spectral data.

Reactions with activated nitriles: A new route for the synthesis of new pyridine and pyrazolopyridine derivatives

It has been found that α, β-unsaturated nitrile derivatives1–3 reacted with S-methylisothiourea to give the propene derivatives4–6 respectively. Cyclisation of4–6 using ethanolic hydrochloric acid afforded the pyridine derivatives7–9 in good yields. On the other hand, the reactions of hydrazine hydrate and of phenylhydrazine with each of7–9 gave the corresponding pyrazolopyridine derivatives10–15. The structures of the newly synthesised derivatives were assigned on the basis of elemental analyses, IR and1H-NMR spectral data studies.

Synthesis of Pyrimidine, Thiazolopyrimidine, Pyrimidotriazine and Triazolopyrimidine Derivatives and their Biological Evaluation

Pyrimidin-4-one-2-thione (3) was synthesized via the reaction of thiourea (1) with ethyl benzoylacetate (2) and was taken as a starting material for the present study via its reactions with the halogen-containing reagents 6a-d and lOa-c to give the corresponding thiazolopyrimidines 8, 9 and 12a-c. The 2-hydrazino derivatives 5 were synthesized either via the reaction of 3 or 4 with hydrazine hydrate. Compound 5 reacted with 6a-c and lOa-c to give the corresponding pyrimidotriazines 17a-c and 19 respectively. Also, compound 5 reacted with the active methylene-containing reagents 13 and 2a,b to give the corresponding 2-pyrazolopyrimidines 15 and 22a,b respectively. On the other hand, the triazolopyrimidines 21a,b and 30a,b were also obtained via the reaction of 5 with each of formic acid, acetic anhydride, ethyl chloroformate and carbon disulfide respectively. Some of the newly synthesized heterocyclic derivatives were tested for their biological activity

Reactions with Pyridine-2-Thiones: A New Route for the Synthesis of Several New Pyridines and Fused Azolo- and Azinopyridines

Abstract The synthetic potential of our newly synthesized 3-cyano-pyridinethione derivatives (la,b) was further demonstrated via their use to synthesize each of 2-S-ethoxycarbonylmethylpyridines (3a,b), thieno[2,3-b] pyridines (4a,b); (7a,b), pyrido[3′2′4,5]thieno[3,2-clpyridazines (8a,b), 2-methylthiopyridines (9a,b), 2-hydrazinopyridines (lOa,b), 3-aminopyrazolo[3,4-b]pyridines (lla,b), pyrazolo[3,4-blpyridin-3-ylphenylthioureas (12a,b), and 3-diazotized aminopyrazolo[3,4-b]pyridine (13a,b) derivatives via their reactions with the corresponding reagents. Structures of the newly synthesized heterocyclic derivatives were established on the basis of elemental analyses and spectral data studies.