Uses of Cyanoaceto Hydrazide in Synthesis of Heterocyclic Compounds of Anticipated Biological Activity..
Yasmeen Mohamed Ali;
Abstract
This work reported the synthesis of some novel thienopyrimidines and annulated heterocycles for evaluation of their antimicrobial properties.
Condensation of thieno[2,3-d]1,3-oxazine 1 with 2-cyanoacetohydrazide 2 in dioxane resulted in the formation of thieno[2,3-d]pyrimidine derivative 3. (Scheme 1)
The functionalities in 2-methyl-3-cyanoacetamido-5,6,7,8-tetrahydro-4H-benzothieno[2,3-d]pyrimidin-4-one 3 made it valuable key precursors for the formation of fused heterocyclic compounds. The reactivity of compound 3 towards various chemical reagents was investigated with the aim to producing thienopyrimidine derivatives with potential biological activities. Thus, the reaction of 3 with salicylaldehyde gave the coumarin derivative 5. On the other hand, the reaction of 3 with either 1,3-diphenyl pyrazole-4-carboxaldehyde or p-anisaldehyde yielded the arylidene derivatives 6 and 7, respectively. (Scheme 1)
Treatment of compound 6 with hydrazine hydrate in boiling dioxane afforded the unexpected product which was identified as 1E, 2E-1,2-bis [(1,3-diphenyl-1H-pyrazol-4-yl) methylene] hydrazine 8. The azine structure 8 was confirmed by comparison (TLC, IR, m.p) with authentic sample prepared from the condensation of 1,3-diphenyl pyrazol-4-carboxaldehyde with hydrazine hydrate in refluxing ethanol. (Scheme 1)
The reactivity of 3 towards active methylene reagents was investigated. Thus, the reaction of compound 3 with malononitrile in presence of a catalytic amount of piperidine in boiling dioxane afforded the 2-pyridone derivative 9. The same reaction was repeated with ethyl acetoacetate under similar condition yielded the 2-pyridone derivative 11. (Scheme 2)
Also, treatment of compound 3 with 4-methoxy benzylidene malononitrile in refluxing dioxane in the presence of catalytic amount of piperidine afforded the 2-pyridone derivative 12 with elimination of the heteryl group. (Scheme 2)
Our study moved to the reactivity of active methylene of the key precursor 3 towards phenyl isothiocyanate in basic dimethylformamide. Thus, subjecting 3 to react with phenyl isothiocyanate followed by acidification of the potassium sulphide salt yielded (Z)-2-methyl-3-(2-cyano-3-mercapto-3-(phenylamino)acrylamido)-5,6,7,8-tetrahydro-4H-benzothieno[2,3-d]pyrimidin-4-one 13. Moreover, the reaction of 3 with phenyl isothiocyanate in ethanolic potassium hydroxide, dimethylformamide and chloroacetyl chloride was added yielded the thiazolidinone derivative 14. (Scheme 2)
2-Amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile 15 has attracted a great deal of interest over the years. The most efficient protocols for carrying out the
Condensation of thieno[2,3-d]1,3-oxazine 1 with 2-cyanoacetohydrazide 2 in dioxane resulted in the formation of thieno[2,3-d]pyrimidine derivative 3. (Scheme 1)
The functionalities in 2-methyl-3-cyanoacetamido-5,6,7,8-tetrahydro-4H-benzothieno[2,3-d]pyrimidin-4-one 3 made it valuable key precursors for the formation of fused heterocyclic compounds. The reactivity of compound 3 towards various chemical reagents was investigated with the aim to producing thienopyrimidine derivatives with potential biological activities. Thus, the reaction of 3 with salicylaldehyde gave the coumarin derivative 5. On the other hand, the reaction of 3 with either 1,3-diphenyl pyrazole-4-carboxaldehyde or p-anisaldehyde yielded the arylidene derivatives 6 and 7, respectively. (Scheme 1)
Treatment of compound 6 with hydrazine hydrate in boiling dioxane afforded the unexpected product which was identified as 1E, 2E-1,2-bis [(1,3-diphenyl-1H-pyrazol-4-yl) methylene] hydrazine 8. The azine structure 8 was confirmed by comparison (TLC, IR, m.p) with authentic sample prepared from the condensation of 1,3-diphenyl pyrazol-4-carboxaldehyde with hydrazine hydrate in refluxing ethanol. (Scheme 1)
The reactivity of 3 towards active methylene reagents was investigated. Thus, the reaction of compound 3 with malononitrile in presence of a catalytic amount of piperidine in boiling dioxane afforded the 2-pyridone derivative 9. The same reaction was repeated with ethyl acetoacetate under similar condition yielded the 2-pyridone derivative 11. (Scheme 2)
Also, treatment of compound 3 with 4-methoxy benzylidene malononitrile in refluxing dioxane in the presence of catalytic amount of piperidine afforded the 2-pyridone derivative 12 with elimination of the heteryl group. (Scheme 2)
Our study moved to the reactivity of active methylene of the key precursor 3 towards phenyl isothiocyanate in basic dimethylformamide. Thus, subjecting 3 to react with phenyl isothiocyanate followed by acidification of the potassium sulphide salt yielded (Z)-2-methyl-3-(2-cyano-3-mercapto-3-(phenylamino)acrylamido)-5,6,7,8-tetrahydro-4H-benzothieno[2,3-d]pyrimidin-4-one 13. Moreover, the reaction of 3 with phenyl isothiocyanate in ethanolic potassium hydroxide, dimethylformamide and chloroacetyl chloride was added yielded the thiazolidinone derivative 14. (Scheme 2)
2-Amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile 15 has attracted a great deal of interest over the years. The most efficient protocols for carrying out the
Other data
| Title | Uses of Cyanoaceto Hydrazide in Synthesis of Heterocyclic Compounds of Anticipated Biological Activity.. | Other Titles | استخدام سيانواسيتو هيدرازيد فى تحضير بعض المركبات الحلقية غير المتجانسة والمتوقع لها نشاط بيولوجى | Authors | Yasmeen Mohamed Ali | Issue Date | 2015 |
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