139452-53-2Relevant articles and documents
Tetrahydropyridine (THP) ring expansion under the action of activated terminal alkynes. The first synthesis and X-ray crystal structure of tetrahydropyrimido[4,5-d]azocines
Voskressensky, Leonid G.,Borisova, Tatiana N.,Kostenev, Innokenti S.,Kulikova, Larisa N.,Varlamov, Alexey V.
, p. 999 - 1001 (2006)
Tetrahydropyridopyrimidines (THPPm) 1-3 underwent tandem cleavage-cyclization piperidine ring enlargement under the action of terminal activated alkynes to produce tetrahydropyrimido[4,5-d]azocines 4-7 in good preparative yields. The latter compounds are representatives of a new heterocyclic system.
Transformations of tetrahydrobenzo[b][1,6]naphthyridines and tetrahydropyrido[4,3-b]pyrimidines under the action of dimethyl acetylene dicarboxylate
Voskressensky, Leonid G.,Borisova, Tatiana N.,Kostenev, Innokenti S.,Vorobiev, Ilia V.,Varlamov, Alexey V.
, p. 1975 - 1979 (2007/10/03)
10-Cyanotetrahydrobenzo[b][1,6]naphthyridines 3, 4 undergo addition of DMAD, followed by a Stevens rearrangement of the intermediate ylide to yield methyl dioates 8 and 9. An alternative transformation sequence starts with migration of the dimethyl butenedioate anion to the carbon of the CN group, followed by the addition of 1 mol of water, to provide succinates 10 and 11. In contrast, tetrahydropyrido[4,3-b]pyrimidines 5-7 undergo a tandem cleavage process, involving one molecule of solvent. The resulting enamines are easily cleaved by strong acids, to give dihydropyrymidinylethylamines, which are scarcely available by other synthetic means.
Dehydrogenation of 6-Azaquinazoline Derivatives. Formation of Unexpected Quinonediimine Intermediates
Huber, Imre,Fueloep, Ferenc,Lazar, Janos,Bernath, Gabor,Toth, Gabor
, p. 157 - 162 (2007/10/02)
2,6-Disubstituted 5,6,7,8-tetrahydropyridopyrimidin-4(3H)-one (6-azaquinazoline) derivatives 7a-e were synthesized from N-substituted 3-methoxycarbonyl-4-piperidones 5a, b and amidines 6a-c.Compounds 7a-d and the debenzylated derivatives 8a-c under
