4- pyrimidine methanol, water

An excellent correlation was determined between octanol-water partition coefficients of 4//-pyrido[ 1,2-a]pyrimidin-4-ones 10 and 11 (R = H, Me, Et R1 = H, Me, Et, nPr R2 = H, Me, Et, Pr) and their RM values measured by TLC on Kieselgel 60 F254 plates with a methanol-water (30 70) mobile phase (82MI9). 

The nitrogen atom necessary for ring closure to give the pyrido[3,2-c/]pyrimidine system may be introduced by heating methyl 3-acetamidopyridine-2-carboxylate with an arylamine in a free flame for a short time or refluxing the reaction partners in a benzene/phosphoryl chloride mixture.37 The reaction of the pyridine-2-carboxylate with hydroxylamine in methanol/water requires two days at room temperature and affords 3-hydroxy-2-methylpyrido[3,2-t/]-pyrimidin-4(3//>one (11).35... 

Additional examples of this fascinating chemistry are listed in Table 1 [9, 10]. For Entries 1-3, the initially formed m-chlorobenzoate product is methanolized to the methyl ether (not shown). Entry 3 represents an attractive synthesis of pyrrolo[3,2-d]pyrimidines [11]. Water is the nucleophile in Entry 4, not m-chlorobenzoate, in a sequence that provides pyrrolo[3,2-c]coumarins [12]. Entry 5 describes the preparation of pyrrolo[3,2-c] [1] benzothi-opyran-4-ones, which is a new ring system and where water has captured the intermediate 3-methylene-2-hydroxy indoline [13]. Entry 6 features the synthesis of pyrrolo[3,2-c]pyrones [14]. Entry 7 describes a similar rearrangement of A-alkyl-A-allenylmethylanihnes with magnesium monoperoxyphthalate (MMPP) to afford 2-vinylindoles [15], This reaction presumably follows the one described earlier, although none of the presumed intermediates could be isolated. 

Pyrimidine derivatives. 2,6-Bis (methylmercapto) - 9- (2, 3, 4, 6 - tetra - O - acetyl) - -D-glucopyranosylpurine dissolved by slight warming in methanol-water, N-chlorosuccinimide added, stirred 2 hrs. at 40-50 , then the solvent evaporated in vacuo 2,6-bis (methylsulfonyl) -9- (2, 3, 4, 6 -tetra-0-acetyl) -y -D-glucopyrano-... 

Hydroxy-L-prolin is converted into a 2-methoxypyrrolidine. This can be used as a valuable chiral building block to prepare optically active 2-substituted pyrrolidines (2-allyl, 2-cyano, 2-phosphono) with different nucleophiles and employing TiQ as Lewis acid (Eq. 21) [286]. Using these latent A -acylimmonium cations (Eq. 22) [287] (Table 9, No. 31), 2-(pyrimidin-l-yl)-2-amino acids [288], and 5-fluorouracil derivatives [289] have been prepared. For the synthesis of p-lactams a 4-acetoxyazetidinone, prepared by non-Kolbe electrolysis of the corresponding 4-carboxy derivative (Eq. 23) [290], proved to be a valuable intermediate. 0-Benzoylated a-hydroxyacetic acids are decarboxylated in methanol to mixed acylals [291]. By reaction of the intermediate cation, with the carboxylic acid used as precursor, esters are obtained in acetonitrile (Eq. 24) [292] and surprisingly also in methanol as solvent (Table 9, No. 32). Hydroxy compounds are formed by decarboxylation in water or in dimethyl sulfoxide (Table 9, Nos. 34, 35). 

A mixture of 2-methylpyrido[3,4-d]pyrimidine-4-one 261 (1 mmol), benzylamine (3 mmol), HMDS 2 (3 mmol), and (NH4)2S04 (0.1 mmol) is heated under reflux for 4—5 h. After cooling, addition of 10 mL ethanol, and evaporation, the residue is recrystallized from water or aqueous methanol to give 97% 2-methyl-4-benzyla-minopyrido[3,4-d]pyrimidine 262, m.p. 156-160°C [74] (Scheme 4.60). 

Extraction of soil with hexane acetone (1 1), centrifugation, separation of hexane from acetone/water layer. Extraction of acetone/water phase with chlorofornrdiethyl ether (1 1), solvent exchanged to methanol. Hexane layer contained diazinon, chloroform/diethyl ether fraction contained 2-isopropyl-4-methyl-6-hydroxy-pyrimidine. 

Gosch and Montag (249) determined and compared the concentration of purines and pyrimidines in different coffees. The freeze-dried extract was dissolved in water, hydrolized with TFA/formic acid at 235°C, and applied to an RP18 SPE cartridge. The eluted sample (with methanol) was analyzed by HPLC on a LiChrosphere 100 RP-18. The mobile phase was a phosphate buffer containing A,A-dimethyloctylamine, and the detection was spectrophotometric at 269 nm. Adenine, guanine, hypoxanthine, xanthine, AMP, GMP, IMP, UMP, and uric acid levels were tabulated for arabica and robusta coffees from various sources. 

Reduction of 6,7,8,9-tetrahydro-4//-pyrido[l,2-a]pyrimidin-4-ones 341 and their quaternary salts 343 with sodium borohydride in water and methanol yielded the thermodynamically stable epimer 342 of 1,6,7,8,9,9a-hexahydro-4//-pyrido[l, 2-n]pyrimidin-4-ones (83SZP635100 85JOC2918),... 

A solution of 6.9 g of sodium in 1 liter of absolute ethanol were treated with 54 g of guanidine carbonate and 31.0 g of 4-amino-a-(anilinemethylene)-3,5-dimethoxyhyrocinnamic acid nitrile and boiled under reflux for 20 hours. 500 ml of water were added and the alcohol was removed in vacuum. After standing at room temperature for 2 hours, the crystallized 2,4-diamino-5-(4-amino-3,5-dimethoxybenxyl)pyrimidine was filtered off under suction, washed with water and recrystallised from methanol melting point 215°-216°C. 

A mixture of 3-(2-bromoethyl)-2-methyl-pyrido[l,2-a]pyrimidin-4-one monohydrobromide, 3-furan-2-yl-methyl-(3H-imidazo[4,5-b]pyridine-2yl)-4-piperidinyl)-amine dihydrobromide, of sodium carbonate and of N,N-dimethylformamide was stirred and heated overnight at about 70°C. The reaction mixture was poured onto water. The product was extracted with trichloromethane. The extract was dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol (94 6 by volume), saturated with ammonia, as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from acetonitrile, yielding 3-(2-(4-((3-(2-furanylmethyl)-3H-imidazo[4,5-b]pyridin-2-yl)amino)-l-piperidinyl)ethyl)-2-methyl-4H-pyrido[l,2-a]pyrimidin-4-one melting point 202°C. 

The mesoionic 1-alkyl-1,2,4-triazolo[4,3-c]pyrimidinium-3-aminides 37 were incapable of undergoing Dimroth rearrangement the 5-alkenyl-l,2,4-triazolo[4,3-c]pyrimidines 78, formed as a consequence of pyrimidine ring lysis with water, methanol, or ethanol at room temperature, were incapable of recyclization [97JCS(P2)49] (Scheme 33). 

With 6-aminouracil, prop-2-ynal or 3-phenylprop-l-yn-3-one in aqueous alkali at 0°C reacts to furnish pyrido[2,3-phenyl derivative 232 similarly, methyl propiolate and l,3-dimethyl-6-aminouracil (33) in refluxing water give 1,3-dimethylpyrido[2,3-c/]pyrimidine-2,4,7(177,3//,8//)-trione (34).165 In protic media such as water or methanol, irrespective of the N1 substituent, the reaction with 6-aminouracils largely yields methyl 2,4,7-trioxo-l,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidine-5-carboxylates.I42,165,547,584... 

Krepelka et al. (102) described oxidative transformations of some 10+ pyrimidine derivatives into oxazoiidine derivatives and their purity testing using silica gel plates or on reflex foils Silufol UV254 using 1-propanol-ammonia-water (7 1 2) or chloroform-methanol-ammonia (2 2 1) with UV detection at 254 or by chlorination. 

The chemical structure of thiamine is shown in Figure LA pyrimidine moiety (2-methyl-4-amino-5-hydroxymethylpyrimidine) and a thiazole moiety (4-methyl-5-hydroxyethylthiazole) are connected by a methylene group. The double-salt form of thiamine with hydrochloric acid (C12H17N4OSCI-HCI molecular weight 337.28) is readily soluble in water, less soluble in methanol and glycerol, nearly insoluble in ethanol, and insoluble in ether and benzene (1). 

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