- The promoted synthesis of minoxidil by magnetic nanoparticles of cobalt ferrite (CoFe2O4) as a heterogeneous reusable catalyst
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Minoxidil (2,4-diamino-6-piperidinopyrimidine 3-oxide) was primarily recognized as a drug for reducing vascular resistance to blood flow. It was later introduced as a more important medicine for topical stimulation of hair growth and baldness reverting as well as treatment of androgenic alopecia through increasing prostaglandin endoperoxide synthesis. In this study, magnetic nanoparticles (MNPs) of spinel ferrites (MFe 2 O 4, M = Co, Ni, Fe, Cu, and Zn) via solid-state grinding procedure were prepared and then characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, and Fourier transform infrared techniques. The prepared nanoferrites were utilized as efficient and green heterogeneous catalysts for N -oxidation of 2,6-diamino-4-chloro-pyrimidine with H 2 O 2 in refluxing ethanol giving 2,6-diamino-4-chloro-pyrimidine N -oxide as a starting material for the synthesis of 2,4-diamino-6-piperidinopyrimidine 3-oxide (minoxidil). Among the examined nanoferrites, CoFe 2 O 4 MNPs exhibited prominent catalytic activity giving the product in 95% yield within 60 min. Moreover, the reusability of nano-CoFe 2 O 4 was examined for 6 consecutive cycles without significant loss of catalytic activity and magnetic property.
- Eisavi, Ronak,Ahmadi, Fatemeh,Zeynizadeh, Behzad,Kouhkan, Mehri
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- AN IMPROVED PROCEDURE FOR THE PREPARATION OF AROMATIC HETEROCYCLIC N-OXIDES
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An improved procedure for the preparation of aromatic heterocyclic N-oxide is described.Nitrogen containing heterocyclic compounds gave their N-oxides in excellent yields by the reaction of m-CPBA in DMF/MeOH in the presence of HF in a short time under mild reaction conditions.The presence of HF and MeOH is crucial for the reaction.
- Rhie, Soo Young,Ryu, Eung K.
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p. 323 - 328
(2007/10/03)
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- A process for the preparation of 2,4-diamino-6-(1-piperidinyl)-pyrimidine N-oxide
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A process for the preparation of 2,4-diamino-6-(1-piperidinyl)-pyrimidine N-oxide which process consists in reacting 6-chloro 2,4-diamino-pyrimidine of formula II with the monoperphthalic acid magnesium salt, of formula VI to obtain 2,6-diamino-4-chloro-pyrimidine N-oxide of formula VII which is reacted with piperidine to give desired compound I.
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- Process for the preparation of oxadiazolopyrimidine derivatives
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A process for preparing oxadiazolopyrimidines of the formula STR1 wherein R is alkyl or alkoxyalkyl, by reacting a compound of the formula STR2 wherein R is as set forth above, with phosgene, is described.
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- Oxadiazolopyrimidine derivatives
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Alkyl or alkoxyalkyl 5-[3,6-dihydro-1(2H)-pyridyl]-2-oxo-2H-[1,2,4]-oxadiazolo-[2,3-a]primidine-7-carbamates, prepared, inter alia, from the corresponding 6-[3,6-dihydro-1(2H)-pyridyl]-2,4-pyrimidine-dicarbamate-3-oxide, are described. The end products are useful in the treatment of vascular-conditioned hypertension or as vasodilators in the case of peripheral blood supply disorders.
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- Substituted oxadiazolopyrimidines
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Oxadiazolopyrimidine derivatives of the formula STR1 wherein R and R1 are as hereinafter described, prepared, inter alia, by cyclizing a compound of the formula STR2 wherein R and R1 are as hereinafter described. The end products are useful in the treatment of vascular-conditioned hypertension or as vasodilators in the case of peripheral blood supply disorders.
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