Pyrimidines acylation

It is mentioned in an early paper on the effect of water on Heck vinylations [62] that 2,4-dimethoxy-5-iodopyrimidine reacted with 1-(ethoxyethenyl)-tri-n-butylstannane to afford an acylated pyrimidine derivative in 83 % yield (via in situ hydrolysis of the intermediate enol ether) (Scheme 6.28). 

Diethyl pyrimidin6-4,5-dicarboxylates react readily with hydrazine to give pyrimido-[4,5-df]pyridazine-5,8-diones (72CPB1513). In a similar manner the acyl pyrimidines (202) react with hydrazines to give the products (203) (76BSF1549). Hydrazines also react with... 

Using similar chemistry l,3-diaryl-2-thiobarbituric acid is acylated with chloroacetyl chloride in the presence of triethylamine. Subsequent (9-alkylation under the mildly basic conditions of sodium acetate yields the 5-oxo derivative <91H(32)907>. It is not necessary to use barbituric acid derivatives to accomplish synthesis of furopyrimidines. Other 6-oxopyrimidines serve well in developing analogues. For example, in a reaction similar to that described above, the acylated pyrimidine (215) undergoes cyclization to a 4-(substituted)amino compound (216) (Equation (74)) <92MI 707-03). 

The transglycosylation method for the introduction of a sugar in a purine base is unique and often useful, especially for the synthesis of purine nucleosides of functionalized sugars that are difficult to prepare by conventional procedures, e.g. formation of 19. The transfer of the ribosyl moiety of acylated pyrimidine nucleosides to purines has been accomplished in the presence of a Lewis acid catalyst. ... 

Dimethylisoxazol-5-amine is easily acylated to its formyl derivative (697) which, on catalytic hydrogenation, undergoes ring cleavage and recyclization to yield 5,6-dimethyl-pyrimidin-4(3H)-one (698) other acyl derivatives give analogous 2-substituted pyrimidines... 

Acylation of 2-methylpyrido[2,3-d]pyrimidines with anhydrides gives 2-acylmethyl derivatives (67), whilst bromination to the 7-bromomethyl derivative has been reported for 7-methylpyrido[3,2-d]pyrimidines (56JCS4433) in a synthesis of potential folic acid antagonists. 

A rare type of reaction involves the photocyclization of the 5-(unsaturated acyl)aminopyrimidines (168) to reduced 7-methylpyrido[3,2-Similar reactions are known involving related 4-aminopyrimidine derivatives, leading to pyrido[2,3-[Pg.221]

Benzopyridodiazines, 3, 199-262 Benzo-2-pyridone tautomerism, 2, 346 Benzo-4-pyridone tautomerism, 2, 346 Benzopyridones acylation, 2, 352 alkylation, 2, 349 Benzopyrido[3,2-ii]pyrimidine reactions... 

Pyrido[2,3-(i]pyrimidine, /3-ketoalkyl-deacylation, 3, 212 Pyrido[2,3-(i]pyrimidine, methyl-deuterium exchange, 3, 212 Pyrido[2,3-(i]pyrimidine, 2-methyl-acylation, 3, 210... 

Pyrimidin-5-amine, 4-methylamino-synthesis, 3, 121 Pyrimidin-5-amine, 4-oxo-purfne synthesis from, 5, 582 Pyrimidinamines acylation, 3, 85 alkylation, 3, 86 basic pXa, 3, 60-61 diazotization, 3, 85 Dimroth rearrangement, 3, 86 electrophilic reactions, 3, 68 Frankland-Kolbe synthesis, 3, 116 hydrolysis, 3, 84 IR spectra, 3, 64 N NMR, 3, 64 nitration, 3, 69 Principal Synthesis, 3, 129 reactivity, 3, 84-88 structure, 3, 67 synthesis, 3, 129 Pyrimidin-2-amines alkylation, 3, 61, 86 basic pK , 3, 60 diazotization, 3, 85 hydrogenation, 3, 75 hydrolysis, 3, 84 mass spectra, 3, 66 Pyrimidin-4-amines acidity, S, 310 alkylation, 3, 61, 86 basic pXa, 3, 61 Schifi base, 3, 85 synthesis, 3, 110, 114 1,3,5-triazines from, 3, 518 Pyrimidin-5-amines basic pXj, 3, 61 hydrogenation, 3, 75 reactions... 

Pyrimidine-2-sulfonyl chloride, 4,6-dimethyl-reactions, 3, 97 Pyrimidinesulfonyl halides reactions, 3, 97 Pyrimidinethiols S-acylation, 3, 95 S-alkylation, 3, 94 oxidation, 3, 94 synthesis, 3, 135 Pyrimidine-5-thiols oxidation, 3, 94 synthesis, 3, 136... 

Acid chlorides, acetic anhydride,and formamide have also been used to synthesize pyrido[2,3-d]pyrimidines from 2-ammo-nicotinamides, although in the last case high temperatures were necessary. It is suspected that all the foregoing eyclizations proceed via initial acylation of the 2-amino group to yield an intermediate 2 - amidonicotinamide. 

Good yields of pyrido[2,3-d]pyrimidiries (37) were also oblaiiied by the action of formamide on o-amino nitriles (36). Reduction of 2-amino-4,6-dimethylnicotinitrilc yields the 3-aminomcthyl compound (38). Acylation to the 3-aoylaminomethyl derivative (39), followed by cyolization, by means of heat or phosphoryl chloride, yielded the dihydropyrido[2,3-d]pyrimidines (40). ... 

V. Acyl acetates. j8-Keto esters have proved useful for the preparation of pyrido[2,3-d]pyrimidin-7(8H)-ones bearing alkyl and aryl... 

---