2-bromo-4-phenyl pyrimidine

Comparison of this reactivity order with that found in the amination of 2-X-4-phenyl pyrimidines (SCH3 Br = Cl > F > SO2CH3 I > (013)3 > CN see Table 11.5 in Section ll,C,l,d) shows that these reactivity orders differ considerably. The fluoro substituent, especially, which has in the pyrimidine series about the same reactivity order as the chloro or bromo atom, shows in the 1,2,4-triazine series a low ANRORC activity. Comparison of both series of reactivities is, however, a delicate matter, mainly because the yields obtained for the amino compounds in the 1,2,4-triazine series are much lower than those obtained in the pyrimidine series, because of the occurrence of many side reactions, such as ring contraction, dehalogenation, ring transformations, and degenerate ring transformations... 

The ANRORC mechanism is also supported by the isolation of a small amount of the open-chain 3-amino-l-phenylallylidene cyanamide (36) (Scheme 2) from the products of the reaction of 2-bromo-4-phenyl-pyrimidine as formed from an adduct structurally related to 35a.100... 

Isoxazolo[4,5-d]pyrimidine, 7-bromo-5-chloro-X-ray, 6, 618 <72J8X(2)251) Isoxazolo[4,5-d]pyrimidine, 5,7-dichloro-3-phenyl-UV, 6, 620 <67X675)... 

Pyrimidine, 5-benzyl-4,6-dimethyl-2-phenyl-synthesis, 3, 118 Pyrimidine, 2-benzyl-5-nitro-synthesis, 3, 130 Pyrimidine, benzyloxy-pyrimidinone synthesis from, 3, 133 Pyrimidine, 4,5-bis(alkylamino)-synthesis, 3, 121 Pyrimidine, 2-bromo-aminolysis, 3, 100 H NMR, 3, 62 reactions... 

Pyrimidin-2( 1H) -one, 4-benzyl-5-phenyl-3,4-dihydro-synthesis, 3, 118 Pyrimidin-2(1 H)-one, 5-bromo-thiation, 3, 89... 

Reaction of 7-bromo-2-butoxy-3-phenyl-4//-pyrido[l, 2-u]pyrimidin-4-one (203, R = Bu, Ar = Ph) and (4-ClPh)BH2 in the presence of a 2 M solution of Na2C03 and (Ph3P)4Pd afforded 7-(4-chlorophenyl) derivative... 

Heating 6-bromo- and 6-chloro-2-halomethyl- (99JHC1065) and 6-bromo-, 6-chloro- and 6-fluoro-2-phenyl-4/f-pyrido[l, 2-u]pyrimidin-4-ones (00JMC2814) in phenyl ether at 220 °C for 10 min yielded the appropriate 7-halo-1,8-naphthyridin-4-ols. 6-Amino-2-trifluoromethyl-4//-pyrido[l, 2-a]-pyrimidin-4-one was transformed into 7-amino-2-trifluoromethyl-l,4-dihy-dro-l,8-naphthyridin-4-one in 90% yield (98EJM383). 

The reaction of potassium 3-amino-4-oxo-3,4-dihydroquinazoline-2-thiolate 62 with a-bromophenylacetic acid 63 resulted in the formation of (3-amino-4-oxo-3,4-dihydroquinazolin-2-ylsulfanyl)-phenyl-acetic acid methyl ester 64 which on alkali treatment and subsequent acidification resulted in the synthesis of 2-phenyl- 1-thia-4,4a,9-triaza-anthracene-3,10-dione 65 <1999JCR(S)86>. Similarly, the reaction of potassium 3-amino-5,6-dimethyl-4-oxo-3,4,4a,7a-tetrahydrothieno[2,3- pyrimidine-2-thiolate 66 with a-bromo-ester 67 resulted in the formation of 2-(3-amino-5,6-dimethyl-4-oxo-3,4,4a,7a-tetrahydrothieno[2,3- / pyrimidin-2-ylsulfanyl)-propionic acid ethyl ester 68. Subsequent treatment with alkali followed by acidification resulted in the formation of 2,3,7-trimethyl-3a,9a-dihydro-l,8-dithia-4a,5,9-triazacyclopenta[ ]naphthalene-4,6-dione 69 <2000JHC1161>... 

Extension of these amination studies to 4-phenyl-, 4-methoxy-, and 4-piperidino-5-bromo[l(3)- N]pyrimidine revealed that also these com-... 

The potassium salt of 7-methyl-3-phenyl-2,4-dioxo-l,2,3,4-tetrahydropyrido[2,3- pyrimidine-5-carboxylate 153 was condensed with l-bromo-3-chloropropane or 1,4-dibromobutane in anhydrous DMF at room temperature to afford the A-l-alkyl derivatives 154 and 155, respectively <1994FA499>. The corresponding A-l-piperazinylalkyl derivatives of 153 were also prepared in more than 40% yield. Debenzylation of 6-benzyl-3-methylpyrido[4,3-,7 pyrimidine 156 by Pd/C-catalyzed hydrogenolysis in AcOH gave the analogue 157 <1994JHC1569>. 

On being heated with 5" aqueous alkali, 3-bromo-2-phenyl-4-oxo-4//-pyrido[l,2-a]pyrimidine was transformed to 2-phenylimidazo[l,2-u]pyri-dine, whereas the 2-methyl analog in 7"0 aqueous potassium hydroxide yielded a mixture of the 3-unsubstituted- and 3-carboxy-2-methylimidazo-[l,2-u]pyridines. Under similar conditions, 3-bromo-2-chloro- and 3-bromo-4-oxo-4ff-pyrido[l,2-a]pyrimidines decomposed to 2-aminopyridine.294... 

The halogen metal exchange reaction between 7-bromo or 7-iodo-3-phenyltriazolopyrimidine 165 and butyllithium in iV,N,N, N -tetra-methylethylenediamine afforded the 7-lithio compound 166, whereas a similar reaction with the 7-chloro derivative 165 (R = H) gave the ring-fission product, 5-amino-l-phenyl-l//-l,2,3-triazole-4-carbonitrile 169 (91 CPB2793). Reaction of 166 with electrophiles such as benzaldehyde and ketones gave 170 and 167 respectively, together with 7,7 -bis[3-phenyl-3//-1,2,3-triazolo[4,5-d]pyrimidine] 168 (Scheme 34). 

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