On the chichibabin amination of pyrimidine and N‐alkylpyrimidinium salts using liquid ammonia/potassium permanganate

Abstract

Treatment of the 2‐R‐pyrimidines (1, R = methyl, ethyl, i‐propyl and t‐butyl) with potassium amide/liquid ammonia/potassium permanganate leads to amination at C‐4(6). The yields of the 4(6)‐amino compounds 3 in‐crease in the order 2‐methyl (10%), 2‐ethyl (30%), 2‐i‐propyl (45%) and 2‐t‐butyl (60%). Treatment of the 2‐R‐N‐methylpyrimidinium salts (4, R = hydrogen, methyl) with liquid ammonia/potassium permanganate leads to a regiospecific imination at C‐6, the corresponding 2‐R‐1,6‐dihydro‐6‐imino‐1‐methylpyrimidines 6 being obtained in 80‐85% yield. It is proved by 15N‐labelling that no ring opening is involved in these imination reactions. Treatment of the imino compounds with base leads to the corresponding 2.R‐6‐methylamino‐pyrimidines 8, involving, as proved by 15N‐labelling, an ANRORC‐mechanism. 2‐t‐Butyl‐1‐ethylpyrimidinium tetrafluoroborate (9b) when treated with liquid ammonia/potassium permanganate undergoes N‐deethylation, 2‐t‐butylpyrimidine being exclusively formed.

Reactions of 4-(trihalomethyl)quinazolines with aliphatic amines. Role of the halogen atom and of the amine on the reaction pattern

“…The parent compound of amide 5 could be orthoamide 10, but any attempt to isolate it, by using anhydrous reagents, failed. 4-Hydroxyquinazoline (6) is the product of an aromatic substitution by water probably present in the reaction mixture.…”

Nitromethylenation of N-methylpyridinium salts

“…The solid was separated and was identified as piperidine hydrochloride (0.08 g). The reaction mixture, after the removal of the solvent, was subjected to column chromatography (silica gel, 1:1 benzene/ethyl acetate), and two products were obtained: the first one (0.06 g) [mp (petroleum ether) 90-91.5 °C; NMR (CD3COCD3) 1.65 (m, 6 H, NCH2CR2CH2), 3.15 (m, 2 H, NHCH2CH2CH2), 3.80 (m, 2 H, NC/f2CH2CH2), 7.50-8.00 (m, 4 , H5-H8), 9.20 (s, 1 H, H-2); mass spectrum caled for C14H15N30 (M+) m/e 241.121 503, found 241.12104] was identified as 4-(lpiperidylcarbonyl)quinazoline (5) (yield 25%), and the second one (0.06 g) was identified as 4-hydroxyquinazoline14 (6) (yield 41%).…”