154866-95-2Relevant academic research and scientific papers
Microwave assisted synthesis of some new thiazolopyrimidine, thiazolodipyrimidine and thiazolopyrimidothiazolopyrimidine derivatives with potential antioxidant and antimicrobial activity
Youssef, Mohamed M.,Amin, Mahmoud A.
, p. 9652 - 9667,16 (2020/08/31)
Biginelli reaction of ethyl acetoacetate, thiourea and the appropriate aromatic aldehyde was used to produce ethyl 4-aryl-6-methyl-2-thioxo-1,2,3,4- tetrahydropyrimidine- 5-carboxylates, that reacted with bromomalononitrile to give ethyl 3-amino-5- aryl-2-cyano-7-methyl-5H-thiazolo[3,2-a]pyrimidine-6- carboxylates rather than the isomeric 7H-thiazolo[3,2-a]pyrimidines. Thiazolopyrimidine derivatives reacted with carbon disulphide to yield ethyl 9-aryl-7-methyl-2,4-dithioxo-2,3,4,9-tetrahydro-1Hthiazolo[ 3,2-a:4,5-d'] dipyrimidine-8-carboxylates, that reacted with phenacyl bromide to produce ethyl 8-methyl-10-(4-methoxyphenyl)-3-substituted-5-thioxo-2(un)subatituted- 10H-thiazolo[3'',2'':1',2']pyrimido[4',5':4,5]thiazolo[3,2-a] pyrimidine-9-carboxylates. The aforementioned reactions were carried out using both conventional chemical methods and with the assistance of microwave irradaition. Comparison between both methods showed that the microwave assisted method is preferable because of the time reduction and yield improvements achieved. The new compounds were tested for their biological activity as antioxidants, antibacterial or antifungal agents. Some of the new compounds were found to have moderate to good antioxidant and antimicrobial activities.
A convenient synthesis of thiazolopyrimidines, thiazolodipyrimidines and heterocyclothiazolopyrimidines
Sherif,Youssef,Mobarak,Abdel-Fattah
, p. 9561 - 9572 (2007/10/02)
Ethyl 4-aryl-6-substituted-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxyla tes 1 reacted with bromomalononitrile (2) to give ethyl 3-amino-5-aryl-2-cyano-7-substituted-5H-thiazolo[3,2-a]pyrimidine-6-ca rboxylates 3. The latter compounds reacted with formic acid, hydroxylamine hydrochloride and with formamide to give 9H-3,4-dihydrothiazolo[3,2-a:4,5-b]dipyrimidine-8-carboxylates 5, 1H,8H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidine-7-carboxylates 8 and 2,7-diaminothiazolo[4,5-d]pyrimidine (7), respectively. Compounds 1b,e reacted with chloroacetyl chloride to yield ethyl 5-aryl-3-oxo-7-substituted-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidine-6- carboxylates 9a,b which coupled with arenediazonium chlorides to give the corresponding 2-arylhydrazone derivatives 10a,b. Compound 9a adds α-cyanocinnamonitriles 12a-c to yield ethyl 2-amino-4-aryl-3-cyano-9-(4-methoxyphenyl)-7-methyl-4H,9H-pyrano[2,3-d ]thiazolo[3,2-a]pyrimidine-8-carboxylates 13a-c. Refluxing 1b-d with phenacyl bromide produced ethyl 5-aryl-7-methyl-3-phenyl-5H-thiazolo[3,2-a]pyrimidine-6-carboxylates 14a-c.
