Pyrimidines 3-acyl

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... 

The side chain hydroxy group of 3-(2-hydroxyethyl)-2-methyl-9-methoxy-4//-pyrido[l,2-u]pyrimidin-4-one, and that of its 6,7,8,9-tetrahydro derivative was acylated with MeS02Cl in the presence of NEts in CH2CI2 at room temperature (95MIP4, 96MIP2). The hydroxy group of 2-[4-(4-hydro-xybenzoyl)benzyloxy]-3-methyl-4//-pyrido[l, 2-u]-pyrimidin-4-one, its 6-methyl derivative and 2-[4-(4-hydroxybenzoyl)benzylthio]-3-methyl-4//-pyrido[l, 2-u]pyrimidin-4-one was alkylated with 4-(2-chloroethyl)morpholine hydrochloride and 4-picolyl chloride hydrochloride (96EUP733633). 

Acylation of mesoionic pyrido[l,2-u]pyrimidin-4-ones 150 with aroyl chlorides in the presence of NEts yielded 2-aroyloxy-4//-pyrido[l,2-u]pyrimidin-4-ones 178 (96JHC663). None of the esters 178 could be rearranged to the 2-hydroxy-3-aroyl derivatives 179. The hydroxy group of 9-hydroxy-2-methyl-3- 2-[4-(6-fluoro-l,2-benzisoxazol-3-yl)-l-piperidinyl] ethyl -6,7,8,9-tetrahydro-4//-pyrido[l, 2-u]pyrimidin-4-one was acylated with hexadecanoic acid in CH2CI2 in the presence of dicyclohexylcarbodi-imide and 4-pyrrolidinopyridine at room temperature for 3 days in 80% yield (97MIP7). 

The 3-amino group of 3,4-diamino-2//-pyrido[l,2-u]pyrimidin-2-ones 216, obtained from 3-nitroso derivatives by reduction with Na2S204 in 30% NH4OH at 70-80 °C, was acylated with acyl chlorides, and the acylated products 217 were cyclized to pyrido[2,l-Z)]purin-10-ones 218 by treatment with NaOMe (95JHC1725). 

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