P. S. Lobanov

Acetamidines and acetamidoximes containing an electron-withdrawing group at the α-carbon atom: their use in the synthesis of nitrogen heterocycles (review)*

Published information on heterocyclizations involving acetamidines and acetamidoximes substituted at the α-position with an electron-withdrawing group is reviewed, where these starting materials have been used in the synthesis of 2-aminoazaheterocycles (2-aminopyridines, 2-aminopyrroles, and 2-aminoazirines). In such reactions the α-carbon atom of the amidine or amidoxime is included in the ring of the obtained heterocycle.

Reaction of ethyl 3,3-diaminoacrylate with pyrimidine series o-chloro ketones. Synthesis of pyrido[4,3-d]pyrimidines and 6H-1,3,6,7-tetra-azaphenalenes

Cyclocondensation of ethyl 3,3-diaminoacrylate with 5-acetyl-4-chloropyrimidines gave ortho- and peri-condensed heterocycles formed through substitution of the chlorine atom by the α-carbon atom of the enediamine and condensation of the amino group with the carbonyl or by addition of the amino group to the pyridine ring.

Reactions of 3,3-diaminoacrylic acid derivatives with o-haloarenecarbonitriles. Synthesis of fused azines

The interaction of the ethyl ester or pyrrolidide of 3,3-diaminoacrylic acid with aromatic and heteroaromatic nitriles containing a labile halogen atom in the ortho position, leads to the formation of products of its substitution by the α-carbon atom of the diaminoacrylic acid derivative. The compounds obtained are cyclized smoothly into fused diaminoazines.

Cyclocondensation of 2-Fluoro-5-nitrobenzaldehyde with Amidines. New Synthesis of Isoquinolines

The direction of the cyclocondensation of 2-fluoro-5-nitrobenzaldehyde with five amidines having α-hydrogen atoms has been studied. It was established that depending on the structure of the amidine the main products of the reaction may be not only quinazolines but also 3-aminoisoquinolines. A new convenient route has been found for the synthesis of 3-aminoisoquinolines consisting of the cyclocondensation of α-acylacetamidines with 2-fluoro-5-nitrobenzaldehyde.

REARRANGEMENT OF THE ADDUCTS OF α-(AMINOCARBONYL)- ACETAMIDOXIMES WITH ACYLACETYLENES, LEADING TO 2-AMINOPYRROLE DERIVATIVES*

The rearrangement and cyclization of O-vinylamidoximes, which are adducts of α-(aminocarbonyl)-acetamidoximes with acetylenic ketones, leads to 2-acylaminopyrroles.

N-Amination of unsymmetrically substituted pyrimidines. Synthesis of isomeric N-aminopyrimidones

N-Amination of 6-amino-2-methyl-4-pyrimidone with O-(mesitylenesulfonyl)hydroxylamine leads to the 3-amino derivative. The isomeric 1,6-diamino-2-methyl-4-pyrimidone was obtained by the N-amination of the O-benzoyl derivative of the initial pyrimidone and removal of the benzoyl protection.

N-Amination of 4-Pyrimidones by Mesitylenesulfonyl Hydroxylamine

The 3-amino derivatives are formed exclusively during the amination of the anions of 6-methyl-4-pyrimidones and 2-methyl-4-quinazolone by mesitylenesulfonyl hydroxylamine.