Pyrimidines 2-mercapto-4-methyl

Pyrimido[4,5-d]pyrimidine, 4-mercapto-2-methyl-7-(methylmercapto)-UV, 3, 338 (60JA5711)... 

Alkylthio, arylthio, and thioxo. The thioxo group in pyrimidine-2,4-dithione can be displaced by amines, ammonia, and amine acetates, and this amination is specific for the 4-position in pyrimidines and quinazolines. 2-Substitution fails even when a 5-substituent (cf. 134) sterically prevents reaction of a secondary amine at the 4-position. Acid hydrolysis of pyrimidine-2,4-dithione is selective at the 4-position. 2-Amination of 2-thiobarbituric acid and its /S-methyl derivative has been reported. Under more basic conditions, anionization of thioxo compounds decreases the reactivity 2-thiouracil is less reactive toward hot alkali than is the iS-methyl analog. Hydrazine has been reported to replace (95°, 6 hr, 65% 3deld) the 2-thioxo group in 5-hexyl-6-methyl-2-thiouracil. Ortho and para mercapto- or thio- azines are actually in the thione form. ... 

Hydrolytic fragmentation of the C5-N6 part took place upon heating 7-methyl-5-propyl-2-thioxo-l,2,4-triazolo[l,5-c]pyrimidine (129) with hydrochloric acid. 3-Acetonyl-5-mercapto-l,2,4-triazole (130) and butanoic acid were obtained as a result of N4-C5, C5-N6, and N6-C7 bond cleavages (65JCS3369) (Scheme 50). 

Mercapto-3-methyl-4//-pyrido[],2-rz]pyrimidin-4-one and its 6,7,8,9-tetrahydro derivative were S-alkylated with 4-substituted benzylbromides (96EUP733633). 

Thiamin (vitamin B-l, 177) when photolysed, gives preparations having a characteristic odour. Photolysis of an aqueous solution with a high-pressure mercury lamp is reported to give the pyrimidine (178) [ 113]. Other work used irradiation at 254 nm and concentrated on the approximately 0.1% yield of ether-soluble odoriferous products. As many as nine compounds have been identified (179), (180), (181), 2-methyl-3-formyl-4,5-dihydrofuran, 3-acetyl-4,5-dihydrofuran, 4-oxopentyl formate, 3-formyl-5-hydroxypentan-2-one, 3-mercapto-2-methyl-4,5-dihydrofuran and bis(4,5-dihydro-2-methylfuran-3-yl)disulphide [114, 115]. 

Abstract This presentation is a brief review on the resnlts of our work on iodine interaction with thioamides, selenoamides and amides. The thioamides, benzothia-zole-2-thione (BZT) (1), 6-n-propyl-2-thiouracil (PTU) (2), 5-chloro-2-mercap-tobenzothiazole (CMBZT) (3), N-methyl-benzothiazole-2-thione (NMBZT) (4), benzimidazole-2-thione (BZIM) (5), thiazolidine-2-thione (TZD) (6), 2-mercapto-pyridine (PYSH) (7), 2-mercapto-nicotinic acid (MNA) (8), 2-mercapto-benzoic acid (MBA) (9) and 2-mercapto-pyrimidine (PMT) (10) react with producing three type of complexes of formulae [(HL)IJ(l2) (HL= thioamide and n= 0, 1), [(HL) [I3 ] and [(HL-L)]+[l3 ]. The interaction of seleno-amides, derived from, 6-n-propyl-2-thiouracil (RSelJ) (R= Me- (11), Et- (12), n-Pr- (13) and i-Pr- (14)) with I, have also been studied and produced the complexes [(RSeU)IJ of spoke structure. These complexes are stable in non-polar solvents, but they decompose in polar solvents, producing dimeric diselenide compounds or undertake deselenation. 

Although demethylation, which occurs in the liver, is normally considered to be a catabolic process, it may result in conversion of an inactive form of a drug to the active form. Thus 6-(methylthio)purine (XXXIX) is demethylated by the rat to 6-mercaptopurine [205]. This demethylation occurs in the liver micro-somes and is an oxidative process which converts the methyl group to formaldehyde [204, 207]. The 1-methyl derivative of 4-aminopyrazolo[3,4-d] pyrimidine (XLI) is demethylated slowly, but 6-mercapto-9-methylpurine (XLII) not at all [208]. The A -demethylation of puromycin (XLlIl) [209, 210], its aminonucleoside (XLIV) [211], and a number of related compounds, including V-methyladenine and V,V-dimethyladenine, occurs in the liver microsomes of rodents [212]. In the guinea-pig the rate-limiting step in the metabolism of the aminonucleoside appears to be the demethylation of the monomethyl compound, which is the major urinary metabolite [213]. The relationship of lipid solubility to microsomal metabolism [214], and the induction of these demethylases in rats by pre-treatment with various drugs have been studied [215]. 

H s II H2N-C-NH2 HOyi SH h5c6-n=n Yn CHj 6-Hydroxy-2-mercapto- 4-methyl-S-phenylazo- pyrimidin 70 201 1... 

Pyrimidin 2-Amino-6-mercapto-4-(l-methyl-hydra2ino)- E16a, 727 (Cl - NR-NH2)... 

Pyrimidine 2,6-Dihydroxy-5-(3-mercapto-propyl)-4-methyl-E9b/2, 56 (2-Oxo — 3-Ac — thiolan + Urea)... 

Pyrimidin 5-Acetyl-2-ethyl-4-mercapto-6-methyl- E9b/2, 103 (H5C2-CO-NCS +... 

Pyrimidine 6-Amino-5-cyano-2-mercapto-4-(4-methyl-phenyl)-E9b/2, 80 [Ar —CH = C(CN)2 +... 

Phenacyl bromides react (86JHC43) with anhydro l-amino-5-aryI-2-mercapto-l,2,4-triazolo[3,2-c]quinazolin-4-ium hydroxides (53) through pyrimidine ring-opening and simultaneous formation of the 1,3,4-thiadiazine nucleus to give 54. Compound 514 was also obtained [86JAP(K)61260085] when 2-hydrazino-5-methyl-6/f-l,3,4-thiadiazine (513) was cyclized with aryloxyacetyl chlorides. 

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