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Synthesis and structural study of novel 5‐aryl substituted 2‐amino‐4,7‐dioxopyrido[2,3‐ d ]pyrimidines
Author(s) -
Rodríguez Rená,
Suárez Margarita,
Ochoa Estael,
Pita Beatriz,
Espinosa Remberto,
Martín Nazario,
Quinteiro Margarita,
Seoane Carlos,
Soto Jose L.
Publication year - 1997
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570340338
Subject(s) - chemistry , aryl , pyrimidine , computational chemistry , proton nmr , stereochemistry , carbon 13 nmr , nmr spectra database , medicinal chemistry , spectral line , organic chemistry , alkyl , physics , astronomy
Abstract The tide compounds 4a‐c have been prepared in a one‐step procedure from 2,4‐diamino‐6‐hydroxy‐pyrimidine (1) and the corresponding arylidene substituted Meldrum's acids 2a‐e in very good yields. Semiempirical theoretical calculations (AMI) reveal two favoured conformations ( A and B ) for compounds 4a‐e. The 1 H‐nmr determinations, by using Karplus and Altona equations, clearly indicate that conformation A, with the aryl group on C5 in a pseudoaxial position, is that predominant in solution. The calculated charge density values for the olefinic carbons are in agreement with the experimental push‐pull effect observed in the 13 C‐nmr spectra.