Pyrimidine 4,6-dichloro-2-methyl

Pyrimidine, 4,6-dichloro-2,5-dimethyl-bromination, 3, 77 Pyrimidine, 2,4-dichloro-5-methyl-selenolysis, 3, 101 Pyrimidine, 2,4-dichloro-6-methyl-alcoholysis, 3, 100 Pyrimidine, 4,6-dichloro-2-methyl-reactions... 

Pyrimidin-4-amine, 2,6-dichloro-SchiS base, 3, 85 thioalcoholysis, 3, 101 Pyrimidin-4-amine, 2,6-diethyl-5-methyl-synthesis, 3, 116... 

Methylpyrimidine has been obtained by the present method2 and by a three-step method that begins with the condensation of acetoacetic ester with urea to give 2,6-dihydroxy-4-methyl-pyrimidine the latter is treated with phosphorus oxychloride to give 2,6-dichloro-4-methylpyrimidine, which is reduced by zinc dust and water 8 or by catalytic hydrogenolysis.4... 

In contrast with the Schiff base salen, salicylaldehyde oxime (79) (salox) complexes of Co have received comparatively little attention, but a series of bis-bidentate divalent complexes of the form iraiis-Co(sa 1 ox)2( D M SO)2 have been reported.343 The heterocyclic bidentate oxime violurate (lH,3H-pyrimidine-2,4,5,6-tetrone 5-oximate, Hvi) (80) and its /V-methyl (mvi) and /V,/V -dimethyl (dmvi) derivatives form high-spin divalent [Co(vi)]+ and Co(vi)2 complexes, whereas [Co(vi)3] is low spin.344 The mixed-ligand Co(dmvi)2(phen) complex is also low spin. The crystal structure of m-Co(pxo)2Br2 (pxo = 2-acetylpyridine-l-oxide oxime) is isostructural with the Ni11 relative.345 The dichloro complex also adopts a cis configuration. The tridentate dioximes 2,6-diformyl-4-methylphenol dioxime and 2,6-diacetyl-4-methylphenol dioxime (Hdampo) form binuclear complexes of the type (81a) and (81b) respectively.346 Cobalt oxide nanoparticles were prepared by... 

By reacting 2-aminopyridine and epichlorohydrin, Knunjanz187 obtained the hydrochloride of 3-hydroxy-3,4-dihydro-2H-pyrido[l,2-a]pyrimidine (131 R = OH). Analogous products from 4-methyl-, 5-methyl-, 5-halo- and 3,5-dibromo-substituted 2-aminopyridines have been prepared by Soviet workers.188,189 The same products arose from the reaction of 2-aminopyridines and l,3-dichloro-2-propanol.188 189 Klusis and Kuthevicius190 reacted 2-aminopyridine with 3-chloro-1,2-propanediol (127) or 2,3-... 

Conformational analysis of some 9-chloro- and 9-bromo-6,7,8,9-tetrahy-dro-4//-pyrido[ 1,2-a]pyrimidin-4-ones 31 and their 9,9-dichloro and 9,9-dibromo derivatives was also carried out by I3C NMR spectroscopy (83JHC619). The halogen atoms in the 9-chloro and 9-bromo derivatives 31 (R = H) in the predominantly half-chair conformation occupy the pseudoaxial position. This conformer is probably stabilized by a favorable orbital interaction, while the other one, with a presudoequatorial halogen atom, is destabilized by the unfavorable dipole-dipole interaction between the 9-halogen and C(9a)=N(l) bonds. The methyl group in the 6-methyl derivatives in predominantly half-chair conformations is in the pseudoaxial position (83JHC619). 

Cyclization of ethyl lV-(2-pyridyl)-2-methyl)- and VV-(5-chloro-2-pyridyl)-malonamates in a mixture of POCl3 and PPA at 130 °C gave 2-chloro-3-methyl- and 2,7-dichloro-4f/-pyrido[l,2-a]pyrimidin-4-ones in 26 and 61% yields, respectively (00BMC751). 

In the cyclization of unsymmetrically substituted 2-(/3-oxoaIkylthio)pyrimidines a mixture of two isomers may be obtained. Sometimes the choice of reaction conditions coupled with substituent effects may lead to exclusive or almost exclusive formation of the one isomer. Thus in the simple case of (427) preferential cyclization at N-3 results in the absence of a 4-substituent as in (428), whereas almost exclusive formation of the other isomer (429) results in the methyl derivative (R1 = Me) (67JHC577). In the dichloro analogue (430) both the steric and electronic effects from the vicinal chlorine account for the formation of the 5-oxo product <75ACS(B)1092>. 

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