This paper describes the photophysical properties of a series seven selected examples 5-(alkyl/aryl/heteroaryl)-2-methyl-7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidines (3), which contain alkyl, aryl, and heteroaryl substituents attached to scaffolds 3. Given electron-donor groups -withdrawing groups, optical absorption emission in solid state solution showed interesting results. Absorption UV–Vi...

BACKGROUND Isoxazoles exhibit interesting biological activities, and the 1,3-dipolar cycloaddition(13DC) reactions play an important role in both mechanistic and synthetic organic chemistry. Pyrazoles and annulated pyrazoles exhibit some diverse biological activities. They are used as antipyretic, analgesic drugs, tranquilizing, and herbicidal agents. Pyrazoles are also used extensively as usef...

Seven pyrimidines with a lipophilic substituent at position 5 have been investigated with respect to inhibition of both dihydrofolate reductases of Sarcoma 180 and Escherichia coli and site of inhibitory action in mammalian cells in culture. Of the 7 pyrimidines, 5 were competitive inhibitors of both dihydrofolate reductases, 1 was noncompetitive, and 1 produced no effect. The Sarcoma 180 enzym...

Photoalkylation, the ultraviolet irradiation of DNA with isopropanol and di-tert-butylperoxide, causes a variety of base alterations. These include 8-(2-hydroxy-2-propyl)guanines, 8-(2-hydroxy-2-propyl)adenines and thymine dimers. An E. coli endonuclease against photoalkylated DNA was assayed by conversion of superhelical PM2 phage DNA to the nicked form. Enzyme activities were compared between...

Some aromatic aldehydes are subjected to react with urea (or thiourea) and acetyl acetone in a one-pot Biginelli-type cyclocondensation reaction to give 5-acetyl-4-aryl-6-methyl-1,2,3,4-tetrahydro-pyrimidines 2a-j. Aldehydes with ortho-hydroxy substituent namely salicylaldehyde and 2-hydroxy-3-methoxybenzaldehyde undergo Michael-type addition of the hydroxyl-proton to the C5−C6 double bond of t...

2,2'-disubstitutedamino-4-4'-bis-pyrimidines (3a-m) have been prepared by linking 2,4-dichloro-6-methyl-5-nitropyrimidine (1) with several diamines and subsequent reaction with suitable amines. some of these compounds (3c and 3j) which were reduced catalitically, on treatment with nitrous acid, urea in pyridine, and boiling thionyl chloride gave the corresponding bistriazolopyrimidin ...

Substituted pyrido[3,2-d]pyrimidines are accessible by a reaction sequence consisting of HWE-reaction, Z/E-photoisomerization, and ring closure the pyridine ring. Bis-pyridopyrimidines can be obtained from 7-amino-pyrido[3,2-d]pyrimidines.

The synthesis of 5' - deoxynucleoside 5' - phosphonates which contains a 5' - CP bond in place of the 5' -COP bond of the naturally occuring nucleotides is described. The preparation of phosphonate derivatives of acyclo - nucleosides and a simple method for the conversion of 1-? -D-ribofuranosyl pyrimidines to the corresponding 1-? -D-arabinofuranosyl pyrimidines are also explained