Dimethylamino pyrimidine

The cycloaddition reaction of 1,2,4-tiiazines 7V-oxides proceeds differently from the reaction of the corresponding 1,2,4-tiiazines. Thus the 1,2,4-triazine 4-oxide 55 acts only as a diene in the reaction with 1 -diethylaminopropyne to afford 2-methyl-4-(dimethylamino)pyrimidines 111. At the same time the 1,2,4-triazine 4-oxides 55 react with l-(dimethylamino)-l-ethoxyethylene by 1,3-dipolar cycloaddition to give 5-methyl-1,2,4-tiiazines 112 (78CB240). 

Chloro-2-(dimethylamino)pyrimidine was reacted with diethyl aminomethylenemalonate in ethanol in a sealed tube at I40°C for 6 hr to give 4-pyrimidinylaminomethylenemalonate (281) in 73% yield (72USP3673184). 

HN(CH31j rV3 Einleiten von gasformi-gem Dimethylarain in -Nv N[CH3 2 Ww 2-Dimethylamino-pyrimidin 81-86 1... 

Figure 2. Formulas of selected D-A compounds which contain 4-dialkylamino group as an electron donor and reveal dual fluorescence behaviour. Top /)-cyano-A,A-dimethylaniline (I, CDMA) and its model derivatives p-cyano-2,A,A-trimethylaniline (II), p-cyano-2,6,A.A-tetramethylaniline (III, CTMA)./)-aminobenzonitrile (IV, ABN) and l-ethyl-2,3-dihydro-indole-5-carbonitrile (V. BIN). Middle 4-(dimethylamino)pyrimidine (VI), 4-(diethylamino)pyrimidine (VTI), 4-(dimethylamino)-5-methylpyrimidine (VIII), 4-(diethylamino)-5-methylpyrimidine (IX) and 4-(dimethylamino)-pyridine (X). Bottom methyl 4-(dimethylamino)benzoate (XI, DMAMB), ethyl 4-(dimethylamino)benzoate (XII, DMAEB), p-(dimethylamino)-benzaldehyde (XIll) and />-(dimethylamino)acetophenone (XIV).

Glycine ethyl ester hydrochloride (5.5 g, 39 mmol) in DMF (15 mL) was refluxed for 15 min with NaOMe (2.1 g, 39 mmol) in a sealed tube. The mixture was then added to 4-chloro-5-(4-chlorophenyldia7Cnyl)-2,6-bis(dimethylamino)pyrimidine (3.4 g, 13 mmol) in DMF (20 mL) and the mixture heated for 15 min at 60- 70 C. After standing overnight the precipitate was collected, washed with EtOH, then suspended in H20 and filtered. The Solid (3.0 g) was suspended in HOAc (30 mL) and Zn dust (2.4 g) was added. The mixture was relluxed for 1 h then after cooling, the precipitate was collected, washed with HOAc and filtered. The filtrate was evaporated to dryness and the residue was boiled with HzO (10 mL) and after neutralizing and cooling the precipitate was collected (0.98 g). 

Diazines. - Heating 1-benzylpyrazoles with sodamide gives the corresponding 1,2-dihydro-2-phenylpyrimidines. Fair yields of 4-(dimethylamino)-pyrimidines (98) are obtained when the 2-azapentamethinium salts (97) are treated with ammonium acetate/ ... 

A comparison, by variable temperature NMR measurements, of the energy barrier to internal rotation of the dimethylamino group in five-membered heterocyclic structures has included the study of 5-dimethylamino-1,2,4-thiadiazole.260 The compound is iso-7t-electronic with 4-dimethylamino-pyrimidine, and is comparable in the positions of its nitrogen atoms. The observed closeness of their energy barriers reflects the analogies between cyclic isosteric compounds in which a sulfur atom replaces a —CH=CH— group. A variety of other aspects opened up by these measurements have been discussed.260... 

Aryl-6-phenyl-2-methylthio/secondary amino substituted-4(3//)-pyrimidinones were derived from a reaction of N-arylamino substituted 1,3-diaza-1,3-butadienes with substituted ketenes that was analyzed by computational methods <97T13829>. 1,3-Diazines related to 6-amino-4-chloro-5-cyano-2-(dimethylamino)pyrimidine were prepared in one-pot fashion from 1,1-diamino-2,2-dicyanoethylene and phosgeniminium chloride <97SC1223>. Pyrazolo[3,4- /]pyrimidines were derived from 4-substituted 5-aminopyrazole-l-carbothioamides <97JCR(S)352>. Amino-5-(trifluoromethyl)-l,2,4-triazole gave polysubstituted 2-... 

---