A. G. Zavozin

Synthesis of 2-aminothiazole derivatives

The optimum amount of urea for the selective bromination of ketones in DMF has been established. The obtained α-bromoketones have been used for the synthesis of 2-aminothiazoles in situ. A series of compounds with potential biological activity has been synthesized proceeding from chloroacetyl derivatives of 2-aminothiazoles.

1,3-Dihydro-2H-imidazol-2-one Derivatives: Synthesis and Applications (A Review)

1,3-Dihydro-2H-imidazol-2-ones possess biological activity of various types. For example, 1,3-dihydro-2H-imidazol-2-one (I) [1, 2], 1,3-dihydro-4-methyl-2H-imidazol2-one (II) [1], and 1,3-dihydro-4-methyl-5-(4-methylthiobenzoyl)-2H-imidazol-2-one (enoximone, III) [2, 3] exhibit antioxidant properties. Enoximone (III) and 1,3-dihydro-5isonicotinoyl-4-ethyl-2H-imidazol-2-one (piroximone, IV) were reported to possess pronounced cardiotonic activity [4 – 6].

Synthesis of N-Phthaloyl Derivatives of Amino Acids

N-Phthaloyl derivatives of amino acids are used as semiproducts in the synthesis of compounds possessing hypolipidemic [1], analgesic [2], antibacterial [3], and antitumor [4] activity. These N-phthaloyl amino acids (PAAs) are usually synthesized through cyclocondensation of amino acids with phthalic anhydride [5 – 8]. Some PAAs, representing the N-phthaloyl derivatives (VIII – X) of DL-alanine, -alanine, and -aminobutyric acid (GABA), can be also obtained by fusing phthalic acid (I) with the corresponding amino acids (III – V) at 170 – 190°C [9]. However, the possibility of using this method for the synthesis of other PAAs was not considered in [9]. Recently [10] we have demonstrated that glycine (II) can be brought into reaction with I in a medium of boiling propionic acid, which simultaneously performs the functions of solvent and condensing agent. The reaction yielded N-phthaloylglycine (VII) with a yield exceeding 80%. R = H, n = 1 (II, VII); R = CH3, n = 1 (III, VIII); R = H, n = 2 (IV, IX); R = H, n = 3 (V, X); R = H, n = 4 (VI, XI)

Synthesis of 4,5,6,7-tetrahydroindole derivatives

4,5,6,7-Tetraindole derivatives are used as semiproducts in the synthesis of acetylchotinesterase (ACE) inhibitors [ 1 ]. According to [2], tetraindole derivatives I and II (see the scheme below) can be synthesized by intramolecular cyclization of 2-phenacyldimedone (III) followed by amination of the intermediate 6,6-dimethyl-4-oxo-2-phenyl4,5,6,7-tetrahydrobenzofuran (IV) by aniline or 4-toluidine in AcOH.

Meldrum's acid — A reagent for the synthesis of unsaturated γ-lactones and Β-acylacrylic acids

The thermal cyclization of 2,2-dimethyl-5-(2-aryl-2-oxoethyl)-1,3-dioxan-4,6-diones forms 5-aryl-Β,γ butenolides. Regioselective chlorination of 2, 2-dimethyl-5-[2-aryl(alkyl)-2-oxoethyl]-1,3-dioxane-4,6-diones by SO2Cl2 gives the 5-chloro derivatives; these are cleaved by aqueous AcOH to the E-Β-acylacrylic acids, which are synthones for unsaturated γ-lactones.

Short communication. A region-selective method for the synthesis of 4-substituted 2-amino-6-methylpteridines

We provide here the first report of cyclic condensation of 5,6-diaminopyrimidines with 2-benzamidopropanal or 2,2-dihalogenpropanals for the highly selective synthesis of substituted 6-methylpteridines.

Natural Uracils: Synthesis and Chemical Properties (A Review)

The most important and best characterized representatives of natural uracils are unsubstituted uracil (I), thymine (II), and orotic acid (III). Uracil and thymine enter into the composition of nucleic acids, while orotic acid is a biological precursor of uracil [1]. Uracil and thymine were reported to potentiate the antitumor activity of 5-fluorouracil (IV) and 1-(2-tetrahydrofuryl)-5-fluorouracil (tegafur, V) [2 – 8]. Orotic acid was reported to produce a therapeutic effect with respect to cardiological disorders [9 – 12].

Synthesis of N-substituted 3-nitrophthalimides

The N-substituted 3-nitrophthalimides are known to possess antibacterial [ 1], analgesic [2], and vasodilative [3] activity. These compounds can be synthesized by heating 3-nitrophthalic anhydride with amines either without solvent [4] or in acetic acid [5]. / Below we will show that N-substituted 3-Mitrophthalimides are conveniently obtained by cyclocondensation of 3-nitrophthalic acid (I) with amines in the presence of a two-component reagent system CISiMe3DMF. For example, the reaction of compound I with glycine (II), 5-aminovaleric acid (III), 4-aminobenzoic acids (IV), methyl ester of 4-aminobenzoic acid (V), aniline (VI), and p-toluidine (VII) lead to a high yield of the corresponding products (VIIIXIII). By the same token, the cyclocondensation of phthalic acid (XIV) with compounds II and III yield the N-substituted phthalimides XV and XVI:

Synthesis of hydroxyderivatives of 4-methylcoumarin

7-Hydroxy-4-methylcoumarin (V) was reported to produce a choleretic [1] and hepatoprotectve [2] action. This compound is also used as an intermediate for the synthesis of compounds with antibacterial [3] and spazmolytic [4] properties. Coumarin V and some other hydroxyderivatives of 4methylcoumarin are usually obtained by the Pechman reaction, involving polycondensation of twoand three-atomic phenols with acetoacetic ester (AE) in the presence of H2SO4 [I, 5]. A disadvantage of this method is the comparatively low and unstable yield of the target coumarins V and VIII. In this work we propose new efficient twoand threecomponent systems for for the Pechman reaction with resorcinol (1), orcin (I1), pyrogallol (Ill), and hydroquinone (IV): CISiMe3 -CdClz AcOH (A); CISiMe3 -ZnC! 2 -AcOH (B); ClSiMe3 CdCI2 CF3COOH (C); ClSiMe3 ZnCl2 (D) CISiMe 3 H 2 S O 4 (E ) . Cyclocondensations are performed by mixing phenols and AE with reagents at room temperature, and the coumarins ( V VIII) formed during the reaction are extracted by treating the reaction mixture with water.

Synthesis of 5-(arylmethylene)hexahydropyrimidine-2,4, 6-triones

5-(Arylmethylene)hexahydropyrimidine-2,4,6-triones (AP), which exhibit immunodepressive [1], fungicidal [2] and antiinflammatory activity [3], are synthesized by heating barbituric acid (I) with aromatic aldehydes [4-7]. We have demonstrated that this condensation reaction proceeds just as smoothly at room temperature, if a CISiMe3-DMF system is used as the condensing agent. For example, under these conditions acid (I) afforded with benzaldehyde (IIa), m-nitrobenzaldehyde (IIb), p-nitrobenzaldehyde (IIc) and p-methoxybenzaldehyde (IId) the corresponding AP (Ilia-d) in 85-92% yields (see Table 1).