Synthesis of 4-substituted pyrimido [5,4-C] cinnoline derivatives

Reaction of 4-aminocinnoline-3-carboxamide or its 8-methyl derivative 1a, b with triethyl orthoformate and acetic anhydride gave rise to the corresponding pyrimido[5,4-c]cinnolin-3H-4-ones 2a-d. 2-Methylpyrimido derivatives 2c,d could also be obtained via ammonolysis of 2-methyl-1,3-oxazino[5,4-c] cinnolin-4-ones 4a,b. On the other hand, reaction of 1a,b with araldehydes afforded 2-arylpyrimidocinnolines 5a-e. Reacting compounds 2a-d with hydrazine and different amines produced the corresponding 4-substituted amino or hydrazino derivatives 7-9. This revealed the reactivity of the 4-position of 2 towards nucleophilic substitution. Attempts to cyclize 7a-d to triazolopyrimidocinnolines are discussed

Reactions of epoxy chalcone analogues with some nucleophilic reagents

Epoxidation of arylidene alpha-acetothienone [I] was affectd with alkaline hydrogen peroxide. The epoxy derivatives [II] were reacted with certain aromatic amines to give 2-hydroxy alpha-propionothienone derivatives [III], while with hydrazine and phenylhydrazine it afforded the 4- hydroxypyrazoline derivatives [IV] and [V], respectively

Improved synthesis of 5- [2-thienyl] -3-pyrazolecarboxhydrazide, and its use in the synthesis of thenoylpyrazole and pyrazolo [2,3-d] 1,2,4-triazine derivatives

5-[2-thienyl]-3-pyrazolecarboxhydrazide [III] was prepared by a simple high-yield method [91%], rather than the reported tedious low yield method [22%]. It was used for the synthesis of several arylidene [IV] and pyrazolo [2,3-d] 1,2,4-triazine derivatives [V]

Novel thienyl-substituted pyridone and pyridine derivatives, synthesis and antimicrobial activity

A novel series of thienyl-substituted pyridone and pyridine derivatives was synthesized. Treatment of arylidene alpha- acetothienones [I] with ethyl cyanoacetate afforded thienyl substituted cyanodihydropyridones [II] or cyanopyridones [III] depending on the reaction conditions. Likewise, reacting the same chalcone analogues [I] with malononitrile yielded thienyl substitued cyanoaminodihydropyridines [IV] or pyridines [V]. Some of the prepared compounds showed antimicrobial activity against S. aureus and M. phllei

Hydantoia and thiohydantoia derivatives as potential antimicrobial agents: Part I

Several hydantoin and 2-thio analog derivatives have been prepared. Condensation of 3-methyl-2,4imidazolidine-dione [IA] with aromatic aldehydes afforded the corresponding arylidene derivatives. Coupling of 3-methyl-2-thioxo-4- imidazolidinone [IB] with diazonium salts yielded the expected 5-aryl- hydrazone derivatives. In addition, Mannich reaction of [IB] with formaldehyde and certain secondary amines gave the desired products. However, attempts to condense [IA] with formaldehyde and secondary amines under the Mannich conditions were abortive and the same hydantoin also failed to couple with aryl diazonium salts. Five compounds have been screened against selected bacteria and some of them were found to possess moderate to fairly good antibacterial activity

Novel 2-substituted amino nicotin hydroxamic acids

The synthesis of 2-aryl-aminonicotinhydroxamic acids and 1-aryl-3- hydroxy-2,4-dioxo [1H, 3H] pyrido [2,3-d] pyrimidines is described. Reacting 2-chloro-nicotinic acid with arylamines gave 2- arylaminonicotinic acids which were converted to the corresponding methyl esters by reaction with phosphorus penta-chloride and subsequent treatment of the resulting acid chloride with methanol. Treatment of the methyl esters with hydroxylamine gave the desired hydroxamic acids. Reacting the latter compounds with ethyl chloroformate afforded the corresponding 3-hydroxy-pyrido [2,3-d] pyrimidine-diones

Synthesis of novel series of 6-methyl-2- [substituted methyl thio] Pyrimidine derivatives

Several series of 6-methyl-2- [thiosemicarbazide-, thiadiazolyl pyrimidine and triazole-methyl-thio]-4 [1H]-pyrimidinone derivatives have been synthesized. This was achieved by condensation of 6-methyl- 4- [1H]-pyrimidinone-2-yl thio-glycolic acid hydrazine with alkyl and aryl isothiocyanates to afford thiosemicarbazides. [IVa-e] which on cyclization by either 2N sodium hydroxide or concentrated sulphuric acid yielded the triazole [V-ae] and thiadiazole [VIa-e] derivatives respectively. Further, the same hydrazine when reacted with carbon disulphide and hydrazine hydrate, gave the 1-amino-triazole derivative [VIII]. Six compounds were subjected to in vitro testing for antimicrobial activity

Synthesis and evaluation of some 2-, 4-, and 2, 4distributed-6-methyl pyrimidine derivatives for antimicrobial activity

The reaction of 2-amino-4-chloro-, 4-amino-2-chloro-, and 2,4- dichloro-6-methyl-pyrimidines with primary aromatic amines under acidic conditions is presented. 2-, and 4-w substituted thio- ureide-6- methylpyrimidines were synthesized via the reaction of 2-amino-,and 4- amino-6-methylpyrimidine derivatives with aryl- isothiocyanates: Six compounds were evaluated for their antimicrobial activity and most of them showed a moderate activity against B subtilis, E. coli, and A. Niger

Hydantoin and thiobydantoin derivatives as potential antimicrobial agents II

Several hydantoin and 2-thio analog derivatives have been prepared. Condensation of 1,3-dimethyl-1,2,4 imidazolidinedione [IA] and its 2- thio analog [IB] with aromatic aldehydes afforded the corresponding arylidene derivatives. Coupling of [IB] with diazonium salts yielded the expected 5-arylhydrazono derivatives. In addition, reaction of [IB] with formaldehyde and secondary amines gave the expected products. However, attempts to condense [IA] with formaldehyde and secondary amines under the Mannich conditions were abortive, and the same hydantoin failed to couple with aryldiazonium salts. Several trials have been made to prepare a series of 5-hydrazono-1, 3-dimethyl-2,4-imidazolidinediones via desulphurization of the 2-thio analogs, but were unsuccessful. Additionally, the reaction of [IB] with two equivalents of formaldehyde and secondary amines, in the presence of acetic acid, yielded the bis-Mannich bases [IVa and b]. Reaction of [III] with Grignard reagents was studied. Thirteen compounds have been screened against selected bacteria and some of them were found to possess moderate to fairly good antibacterial activity

Synthesis of some mannich bases of 2-, 4- amino and 2,4-Diamino-6-Methylpyrimidines as potential biodynamic agents

The synthesis of certain Mannich bases of 2-, 4-amino, and 2, 4-diamino-6-methylpyrimidines and their antimicrobial and antileukemic activities are described. Likewise, application of the Mannich conditions to 2-amino-4-[p-hydroxyanilino]-, 4-amino-2-[p- hydroxyanilino]-, and 2-amino-4-[p-acetylanilino]-6-methylprimidines using piperazine as the secondary amine afforded the corresponding bis-Mannich bases