2-Pyrimidin-2-thiones

Pyrido[2,3-d]pyrimidine-2-thione, 7-phenyl-reactions, 3, 211 Pyridopyrimidinethiones reactions, 3, 213 Pyrido[2,3-d]pyrimidinethiones reactions, 3, 213... 

Pyrimidine-2-thione, 4,5-diamino-S-alkylation, 3, 94 Pyrimidine-2-thione, dihydrosynthesis, 3, 109... 

Pyrimidine-2-thiones (e.g., 206) have been shown to exist as such by comparison of their ultraviolet spectra with those of both alkylated forms.The ultraviolet spectra of pyrimidine-4-thiones are different from those of 4-alkylthiopyrimidines, therefore the former compounds exist as 207 and/or 208, the predominant form not having been determined. Infrared spectral evidence suggests that quinazoline-4-thione exists as 209 and/or 210 and has been used recently to demonstrate the thione formulation for pyrimidine-2- and -4-thione, pyrazine-2-thione, and quinoxaline-2-thione. In view of this work, the report that X-ray crystallographic evidence supports the mer-... 

Reactions of iV -alkylated or arylated azinium compounds with nucleophiles proceed more readily than those of the parent, uncation-ized azines, and the ring tends to open. The iV -substituent may bring into play an accelerative effect from the London forces of attraction. Increased displaceability of the substituent in iV -alkyl-azinium compounds has been noted for 2-halopyridinium (87) 1-haloisoquinolinium, 4-halopyrimidinium, 4-methoxypyrid-inium (88), 4-phenoxy- and 4-acetamido-quinazolinium (89), 3-methylthiopyridazinium, and 2-car boxymethylthiopyrimidi-nium salts (90). The latter was prepared in situ from the iV -alkyl-pyrimidine-2-thione. The activation can be effectively transmitted to... 

Surprisingly, Kashima et al. (83TL209) reported the formation of individual 1,4-dihydro- and 1,6-dihydropyrimidines on desulfurization of the corresponding pyrimidine-2-thiones with Raney Ni and claimed that no tautomerization occurs under the reaction conditions (heating under reflux in MeOH). 

Treatment of pyrimidine-2-thione 193 with AICI3 in PhN02 yielded 2-(4-benzylphenyl)-6-oxo-6,7-dihydro-4//-pyrido[6,l-a]isoquinolin-4-thione (194) (98MI47). Cyclization of l-(2-carboxyethyl)-l,2,3,4-tetrahydroquina-zoline-2,4-dione (195) in PPA afforded l,2,3,5,6,7-hexahydropyrimido[3,2, l-//]quinazoline-l,3,7-trione (196) (97CHE96). 

The renaissance of the Biginelli MCR can be attributed to the obtained pyrimidine derivatives, which show remarkable pharmacological activity. A broad range of effects, including antiviral, antitumor, antibacterial, anti-inflammatory as well as antihypertensive activities has been ascribed to these partly reduced pyrimidine derivatives [96], such as 9-117 and 9-118 (antihypertensive agents) [97] and 9-119 (ala-adrenoceptor-selective antagonist) [98] (Scheme 9.24). Recently, the scope of this pharmacophore has been further increased by the identification of the 4-(3-hydroxyphenyl)-pyrimidin-2-thione derivative 9-120 known as monastrol [98], a novel cell-permeable lead molecule for the development of new anticancer drugs. Monastrol appears specifically to affect cell division (mitosis) by a new mechanism,... 

Transition Metal Complexes of l-(2-Methylphenyl)-4, 4, 6-Trimethyl Pyrimidine-2-thione Synthesis and Biological Studies... 

Keywords DNA photocleavage, pyrimidine-2-thione, solvent free synthesis... 

Reaction of 4-arylidene-2-phenyl-5(4//)-oxazolones 593 with A-phenacylpyri-dinium bromide proceeds by the same sequence to give oxazolo[5,4-/>]pyridines 594 (Scheme 7.188) while the reaction of 4-(aminomethylene)-2-phenyl-5(4//)-oxazolone 418 and phenyl isothiocyanate gives pyrimidin-2-thiones 595 (Scheme 7.189). In this latter case initial attack of the exocylic amino group produces an intermediate thiourea (not shown) that subsequently cyclizes to 595. 

The formation of tetracyclic thiophene (232) (via 231) by the Thorpe-Ziegler reaction in the presence of N-bromsuccinimide (NBS) represents a special case, because the pyrimidine-2-thione 229 also served as precursor for the CH-acidic alkylation agent 230 (95H2195) (Scheme 59). 

Much coordination chemistry has been carried out with simple pyrimidines and the nucleic acid bases. The crystal structure566 of tetrakis(l-methyl-pyrimidine-2-thione)zinc(II) perchlorate bis(propanone) demonstrates unidentate coordination by the non-methylated (N-3) nitrogen atom, with r(Zn—N) at 2.058 and 2.060 A. The structure of dichlorobis(l-methylcytosine)cadraium(II)567 involves two Cd—Q bonds (2.497 and 2.485 A) and two Cd—N(3) bonds (2.281 and 2.296 A) with approximately tetrahedral stereochemistry. 

C-Enamino-imines obtained by photolysis of l//-pyrimidin-2-ones have been treated with carbon disulfide, giving 2//-l,3-thiazine-2-thiones (22) and/or l-aryl-l//-pyrimidine-2-thiones (23) (Scheme 13) [82JCS(P1)2149]. 

FIGURE 3. Thiocarbonyl ligands involved in Tables 20-25 (a) pyridine-2-thione, (b) pyridine-4-thione, (c) pyrimidine-2-thione, (d) l,3-imidazoline-2-thione, (e) benz-l,3-imidazoline-2-thione, (f) l,3-imidazolidine-2-thione, (g) l,3-thiazoline-2-thione, (h) benz-1,3-thiazoline-2-thione, (i) 1,3-thiazolidine-2-thione, (j) 1,2,4-triazoline-3(5)-thione, (k) 1,2,3,4-tetrazoline-5-thione... 

The treatment of Ar-(2-pyridinyl)acylacetamides 56 with P4SI0 gave 4-substituted 2//-pyrido[l,2-a]pyrimidine-2-thiones 57 in 28% yield [88JCS(D)433]. 

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