Molecular Iodine Promoted Synthesis of New Pyrido[2,3‐d]pyrimidin‐4‐ols

Abstract

A highly efficient synthesis of novel pyrido [2,3-d]pyrimidin-4-ols was developed via an iodine-catalyzed tandem oxidative cyclization under focused microwave irradiation. Pyrido[2,3-d]pyrimidin-4-ols were obtained from easily available 2-amino-4-aryl-6-arylnicotinamides and benzylic amines with good to excellent yields.

Organochromium(II) and Organonitridochromium(V) N‐Heterocyclic Carbene Complexes: Synthesis and Structural Characterization

“…In the IR spectrum of 5 the Cr≡N multiple bond stretching frequency is observed at 1049 cm -1 . (17); C(1)-Cr(1)-C(7) 160.79(8), C(21)-Cr(1)-C(31) 150.00 (7), N(5)-Cr(1)-C(1) 99.61(8), N(5)-Cr(1)-C(7) 99.55 (9), N(5)-Cr(1)-C(21) 104.48 (9), N(5)-Cr(1)-C(31) 105.26(8).…”

“…Commercially available chemicals were purchased from the Aldrich, Acros, Alfa-Assar, or Lvyin Chemical Co and used as received. Compounds 1,3-diisopropyl-4,5-dimethylimidazole-2-ylidene (IPM) [15] and (IPM) 2 CrCl 2 (1) [9] were prepared according to the literature.…”

“…More recently we prepared the NHC-stabilized organic solvent-soluble CrCl 2 in the form of either dimeric [(IPM)CrCl(μ-Cl)(THF)] 2 (IPM = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) or monomeric (IPM) 2 CrCl 2 (1). [9] Compound 1 reacted with CpNa to yield an ionic compound [(IPM) 2 Cr(η 5 -Cp)] + Cp -, which was structurally similar to the above-mentioned [(IMM) 2 Cr(η 5 -Cp)] + Cp -, [7] but, as a different conversion route product. Compounds [(IPM)CrCl(μ-Cl)(THF)] 2 and 1 were further tested to show low to moderate activity for catalyzing the ethylene polymerization upon activation by methylalumoxane (MAO) under varied loadings.…”

Metal‐Free Cross‐Dehydrogenative Coupling (CDC): Molecular Iodine as a Versatile Catalyst/Reagent for CDC Reactions

“…Anovel method has been developed to obtain highly substituted pyrido[2,3-d]-pyrimidin-4-olsf rom readily available2amino-4-aryl-6-arylnicotinamide and benzylamine througho xidative cyclizationu nder microwave irradiation (Scheme 49). [61] The generality of the reactionh as been investigated by performing the reactionw ith both EDGs and EWGs on the phenyl ring of 261.T he reactioni sn ot affected by the nature of the substituents attached, and the desired products are produced in good to excellent yields. Mechanistically,t he process is similar to that described in Scheme 48.…”

“…A novel method has been developed to obtain highly substituted pyrido[2,3‐ d ]‐pyrimidin‐4‐ols from readily available 2‐amino‐4‐aryl‐6‐arylnicotinamide and benzylamine through oxidative cyclization under microwave irradiation (Scheme ) . The generality of the reaction has been investigated by performing the reaction with both EDGs and EWGs on the phenyl ring of 261 .…”