4-Methoxy-5-methyl-2-pyrimidinone

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... 

Cyclocondensation routes also provide access to pyrimidines. 2,3-Disubstituted pyrido[2,3-/i]-quinazolin-4(3//)-ones are obtained via cyclocondensation of 5-aminoquinoline-6-caiboxylic acid with acid chlorides <02SC235>. 5,6,8-Trialkyl-7-methoxy-2-aminoquinazolines are obtained from 1,3-dimethoxybenzenes via cyclocondensation of intermediate dihydrobenzenes with guanidine carbonate <02TL3295>. Diastereoselective intramolecular hetero Diels-Alder cyclization of a pyrazole carboxaldehyde condensed onto 1,3-dimethylbarbituric acid (101) gave polycyclic heterocycle 102 <02T531>. An efficient one-step synthesis of cyclobutene-annelated pyrimidinones 103 from methyl 2-chloro-2-cyclopropylideneacetate and amidines has been... 

Attempts to use basic reaction components other than 2,4-dialkoxy-pyrimidines met with varied success. Thus, the early attempt of Hilbert30 to react a-acetobromoglucose with 4-amino-2-methoxy-pyrimidine (19) failed. On the other hand, when 4-ethoxy-2(lI/)-pyrimidinone (20) or l-methyl-4-methoxy-2(li/)-pyrimidinone (21) was condensed with 2,3,5-tri-O-benzoyl-D-ribofuranosyl chloride, moderate yields were obtained of 3-/9-D-ribofuranosyluracil (22) and its 1-methyl derivative (23), respectively.31... 

In another application, the totally regioselective direct anodic methoxylation of (45)-pyrimidinone-4-methyl carboxylate obtained from L-2,4-diamino butyric acid followed by diastereoselective substitution of the methoxy group by allyl trimethylsilane can be combined with the follow-up decarboxylative methoxylation of the carboxy function after hydrolysis. A second methoxy group exchange by allyl trimethylsilane yields the C2-sym-metrical (4i ,6i )-4,6-diallyl-pyrimidin-2-one enantiomerically pure [Eq. (50)] [246]. 

Cbz Cp DABCO DBU DDQ (DHQD)2CLB (DHQD)2PYR DMF DME DMPU DMSO Et Fmoc HMPA ia KHMDS LDA LiHMDS Me MEM Ms NaHMDS Ph Piv PMB Pr Py (saltmen)Mn(N) benzyloxy carbonyl p 5 -cyclopentadienyl l,4-diazabicyclo[2.2.2]octane l,8-diazabicyclo[5.4.0]undec-7-ene 2,3 -dichloro-5,6-dicyanobenzoquinone dihydroquinidinyl p-chlorobenzoale (see Chart 1) dihydroquinidinyl pyrimidine (see Chart 1) dimethylformamide dimethoxyethane l,3-dimethyl-3,4,5,6-tetrahydro-2(l//)-pyrimidinone dimethylsulfoxide ethyl 9-fluorenylmethoxy carbonyl hexamethylphosphoric triamide inverse addition potassium hexamethyldisilazide lithium diisopropylamide lithium hexamethyldisilazide methyl (2-methoxy ethoxy )methyl methanesulfonyl sodium hexamethyldisilazide phenyl pivaloyl p -methoxy benzyl propyl pyridine nitrido[A,A/-(l,l,2,2-tetramethyl) bis(salicylideneaminato)]manganese (see Chart 1)... 

C8H8CI6N2O2 f 5-Chloro-6-dichloromethylene-4-methoxy-1-methyl-4-tri-chloromethylhexahydro-2-pyrimidinone, 46B, 223 C8H8N2O2S, Cyanomethyl 2-picolyl sulphone, 40B, 225 C8H9NO2S, 2-((Methylsulfinyl)acetyl)pyridine, 40B, 226 C8H10N2S, 2-Ethyl-4-thiocarbamoylpyridine, 39B, 177 C8Hi,BrN2S, 2-Ethyl-4-thiocarbamoylpyridine hydrobromide, 31B, 125 33B, 114... 

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