4-Pyrimidinone ring

Pyrimidinone ring from o-aminocarboxylic acid amides via o-acylaminocarboxylic acid amides Pyrimido[4,5-b][l,8]naphthyrid-4(3Il)-ones... 

Figure 5. contour plots in the plane of the pyrimidinone ring. Sections of 16 A x 14 A. Contour interval as in Figure 3, minimum contour -60 kcal/mol. (a) Experimental (including contributions of all atoms in the molecule), (b) theoretical. 

JHC1269>. An analogous basic hydrolysis of the fused pyrimidinone ring in these heterocyclic systems had been previously reviewed by Knowles <1996CHEC-II(7)489>. 

Keywords Ammonium acetate Nitro compounds Pyridone Pyrimidinone Ring transformation... 

The rather unusual ring opening of the pyrimidinone (381) can be rationalized by an intermediate adduct between the amine and the electron-deficient pyrimidinone ring... 

Substrate analogs characterized by an amide moiety, preferably tied into a pyrimidinone ring. 

The mass spectrometric behavior of the isomeric 2-oxo-2H- and 4-oxo-4 -6,7,8,9-tetrahydropyrido[l,2-<3]pyrimidines was studied under electron-impact induced polarization (97RCM664). The molecular ion of the 2-OXO-2H isomer appeared to be much more stable than that of the 4-oxo-4 isomer. The fragmentation of the molecular ion (M+) of the 4-oxo-4 isomer is related mostly to the saturated piperidine ring, whereas that of the 2-oxo-2H isomer is much more selective, the only significant process is the primary loss of a CO molecule from the pyrimidinone ring via contraction of the ring. Electrospray ionization quadrupole ion-trap mass spectrometric characterization of risperidon (11) was presented and a possible mechanism for the observed fragmentation pattern was... 

Starting with 405, Buchanan et al. synthesized formycin B (387) by an-nulating the pyrimidinone ring. Compound 405 was transformed to the 4-amino-5(3)-carbamoyl-3(5)- 8-D-ribofuranosylpyrazole 415 and then cy-clized with formic acid and de-O-acetylated to 387 [84JCS(P1)2367 84T119 86JCS(P1)1267] (Scheme 116). 

The acyclo analog of formycin B 496, however, was synthesized by annula-tion of the pyrimidinone ring onto the pyrazole ring of 494, as explained in Scheme 134. Acyclo analogs of formycin and 5-aminoformycin B were also prepared according to this approach [85JCS(P1)2087). 

Most cyclizations of acyiaminocarboxamides yield pyrimidinone rings, but when treated with primary amines in the presence of phosphorus pentoxide and TEA hydrochloride, a new pyrimidine ring is formed. 

Attempts to hydrolyse the acylamino group of an acylamino-carboxamide with aqueous alkali resulted in the formation of a pyrimidinone ring [2311] which is also formed in a variant of a well-known reaction (see p. 29) but using sodium methoxide-DMF as the cyclizing agent [3215, 3661],... 

Condensaton of an enone with urea results in cyclodehydration and the formation of a partially reduced pyrimidinone ring. 

A new fused pyrimidinone ring is formed when the oxazinone (36.7) is treated successively with phosphorus oxychloride and anthranilic acid. 

A more versatile method than most of those previously available for the synthesis of triaryloxazolopyridine is based on the cyclization of 4-benzylidene-oxazol-S-one with N-phenacylpyridinium bromide [3152]. Hot phosphorus oxychloride promotes C—C lx>nd formation between a lactam carbonyl and a ring-carbon and the pyrimidinone ring is chlorinated [3093]. Malononitrile in a basic medium converts an alkenyl-lactam into a fused 3-cyanopyridine ring. Yields in this reaction are low and heating for 16 h is necessary [3427]. 

Annulation of a side-chain phosphonium bromide and a carboxamide group [as in compound (46.1)] occurs under base catalysis [2736]. A pyrimidinone ring is... 

The reaction of a side-chain carboxamide with DMFDEA joins the NH to a neighbouring ring-NH and a fused pyrimidinone ring is formed. The same type of reaction may operate in acetic acid when carboxamide and ring-nitrogen are in different rings. 

A new pyrimidinone ring is formed when the 6-benzoyiadenosine (106.11) is dissolved in acetonitrile and irradiated under argon and in the presence of iodine, tetracyanoethene or 1,4-dinitrobenzene. This may be the first report of an oxidative photocyclization of a 1,3-diazahexatriene syst n, N=C—N=C—C=C. 

An ingenious modification of the general method uses 5,6-diaminouracil as a masked unsaturated 1,2-diamine the products can be hydrolysed with cleavage of the pyrimidinone ring finally arriving at 2-amino-pyrazine-3-acids as products. ... 

N-Condensed 5,6-dihydro-4(3H)-pyrimidinone ring from O-alkyllactims and 2-azetidinones... 

Nucleophilic aromatic substitution reactions were employed to place amines on pyrimidine and pyrimidinone rings. As a more economical substitute for Buchwald-Hartwig cross-coupling reaction conditions GeUis and collaborators developed a DMAP-catalyzed, microwave-assisted method to form 4-hetero-arylamino-substituted quinazolines (Scheme 33) (14T8257). Treatment of... 

A soln. of hydrazobenzene, diketene, and some triethylamine in chloroform refluxed 4 hrs. on a steam bath l,2-diphenyl-5-methyl-3-pyrazolone. Y 80%. F. e. s. T. Kato et al., Chem. Pharm. Bull. 23, 456 (1975) f. reactions s. ibid. 23, 365, 452 4(3H)-pyrimidinone ring from diketene cf. Heterocycles 3,723 (1975). 

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