Synthesis and Biological Activity of Oxazolopyrimidines

Abstract

In this work, the synthesis of oxazolo[4,5‐d]pyrimidines and oxazolo[5,4‐d]pyrimidines is reviewed. The review is focused on the construction of the scaffold rather than on its further modification. Nevertheless, selected examples illustrate some of the most common modifications of these scaffolds. The synthetic part is complemented by an overview of their biological activity. This review covers literature and patents from 1967 until the present.

Synthesis and Biological Activity of New 7-Amino-oxazolo[5,4-d]Pyrimidine Derivatives

“…In general, there are two known main methods of synthesis of oxazolo[5,4- d ]pyrimidines, namely, through cyclization of the pyrimidine ring on existing, appropriately substituted, oxazole derivative or through cyclization of the oxazole ring on pyrimidine derivative [ 26 ]. For the first time, this system was synthesized just by using the second method [ 1 ], where 2-mercapto-5-benzoylamino-4-hydroxypyrimidine was cyclized with phosphoryl trichloride (POCl 3 ).…”

“…For the first time, this system was synthesized just by using the second method [1], where 2-mercapto-5-benzoylamino-4-hydroxypyrimidine was cyclized with phosphoryl trichloride (POCl 3 ). Herein, the described series of new oxazolo [5,4- In general, there are two known main methods of synthesis of oxazolo [5,4-d]pyrimidines, namely, through cyclization of the pyrimidine ring on existing, appropriately substituted, oxazole derivative or through cyclization of the oxazole ring on pyrimidine derivative [26]. For the first time, this system was synthesized just by using the second method [1], where 2-mercapto-5-benzoylamino-4-hydroxypyrimidine was cyclized with phosphoryl trichloride (POCl3).…”

Applications of alkyl orthoesters as valuable substrates in organic transformations, focusing on reaction media

“…Synthesis of indole derivatives Zirconium(IV) chloride (ZrCl 4 , 5 mol%) catalyzed the electrophilic substitution reaction of indole (89) with TEOF (5) in a 3 : 1 molar ratio under solvent-free conditions at 50 C to obtain tris(indolyl)methane (90) 143 in a short reaction time (22 min) in excellent yield (95%) (Scheme 24). 144 The regioselective reaction of carbazole (91) with TEOF (5) using p-TSA under solvent-free conditions at 80 C gave 9-(diethoxymethyl)carbazole (92) in 65% yield in 48 h. On the other hand, 4-methoxycarbazole (93) was regioselectively functionalized at the C 1 position via reaction with (5) in the presence of trichloroacetic acid in dichloromethane at room temperature to furnish various carbazole derivatives, such as 4methoxycarbazole-1-carboxaldehyde (94), bis[4-methoxycarbazol-1-yl]methylium trichloroacetate (95), tricarbazolylrnethane (96) according to the reaction conditions (Scheme 25). 145…”

“…In some parts of it, orthoesters were used to prepare oxazolo [4,5-d]pyrimidines and 7-aminooxazolo [5,4-d]pyrimidines. 94 Perillo et al presented a review article entitled "Synthesis and properties of seven-to nine-membered ring nitrogen heterocycles. Cyclic amidines and cyclic amidinium salts" which pointed to the application of orthoesters in synthetic methods.…”

Synthesis of some oxazolo[4,5 d]pyrimidine derivatives and evaluation of their antiviral activity and cytotoxicity

“…A significant number of studies have been carried out on the biological properties of oxazolo [5,4-d]pyrimidines, uncovering their activities as receptor modulators and enzyme inhibitors. 1 However, it seems that oxazolo [4,5-d]pyrimidines have only been synthesized, and that there is little information in the literature concerning their bioactivity. 2 Among these bioactivity reports, inhibition of fatty acid amide hydrolase and monoglyceride lipase 3 by these compounds have been described.…”