6-Methyl-2- pyrimidinone

Figure 2 Crystal structure of the dimer of 2-butylureido, 6-methyl pyrimidinone 2a. 

Preliminary IR spectral studies were said to suggest that pyrimidinones existed as pyrimidinols <50JCS3062) but this conclusion was promptly reversed <52JCS168) on better experimental evidence subsequent comparison with their N- and O-methyl derivatives showed that the pyrimidinones (39a R = H) and (40a R = H) along with their A-methyl derivatives (39a R = Me), (40a R = Me) and (40b R = Me) all exhibited vqo in the range 1600-1700 cm, whereas the methoxypyrimidines (39b R = Me) and (40c R = Me) showed no such absorptions <53JCS33l, 55JCS211). Closer analysis of the spectra for pyrimidin-4-one (40a R= H) showed that the ort/jo-quinonoid form (40a R = H) is the predominant tautomer (see Section 2.13.1.4). 

Pyrimidinones, dihydro-NMR, 3, 62 synthesis, 3, 117 Pyrimidinones, methyl-thiation, 3, 89... 

Literature reports on synthetic methods for the construction of the pyrimidinone core were very limited. Most of the synthetic strategies toward the densely functionalized core fell into two methodologies, which start from the same amidoxime 13 (Scheme 6.3). Route A is a three-step sequence that involves hydrogenation of 13 to prepare amidine 14. Claisen condensation of commercially available a-benzyloxy acetate and methyl tert-butyl oxalate provides the dihydroxyfumarate... 

Kistler KA, Matsika S (2007) Radiationless decay mechanism of cytosine an ab initio study with comparisons to die fluorescent analogue 5-methyl-2-pyrimidinone. J Phys Chem A 111 2650—2661... 

Rappaport HP (1988) The 6-thioguanine/5-methyl-2-pyrimidinone base pair. Nucl Acids Res 16(15) 7253-7267... 

A process research investigation on p38 MAP kinase inhibitors examined the synthesis (on 7 mol scale) of a group of closely related pyrimidinones such as 37, by condensation of a number of arylacetic esters with 4-cyanopyridine and methyl isothiocyanate. Other nitriles were also examined but were much less successful than 4-cyanopyridine 3-cyanopyridine gave a much lower yield and both benzonitrile and 2-cyanopyridine failed completely <06T11714>. 

The action of diazomethane in aqueous 1,2-dimethoxyethane on 4-methoxy-l-/3-D-ribofuranosyl-2(lf/)-pyrimidinone gave, after purification, the corresponding 2 -methyl ether in 37% yield.333 N.m.r. spectroscopy showed that the crude mono-O-methyl fraction contained the 2 - and 3 - isomers in the ratio of 7 2. The 2 -methyl ether proved to be a versatile intermediate, as acid hydrolysis yielded 2 -0-methyluridine, whereas reaction with ammonia or methylamine... 

Synthesis of Enantiomerically Pure p-Amino Acid from 2-tert-Butyl-1-carbomethoxy-2,3-dihydro-4(1 H)-pyrimidinone (S)-p-Tyrosine-O-methyl Ether. 

Alkylation at the 6-position can also be achieved with N -unsubstituted 4-pyrimidinones, via a dianion, when there is an electron-withdrawing group also present at the 6-position. Thus, alkylation of the chiral pyrimidinone 514 (At = -chlorophenyl) gave a 54% yield of the enantiomerically pure methyl derivative 516 via the dianion 515 <1999JOC7885>. 

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