synthesis of 4-(n,n- dimethylamino)-3-aryl-3-butene-2-one, ethyl-5-aryl-4-oxo-4h-pyran-2-carboxylate, ethyl-5-aryl-4-pyridones-2-carboxylate and 5-aryl-3-cyano-5-methyl-2-pyridones (aryl=3-thienyl, 2-furyl) are described.

Highly substituted 4H-pyrans can be smoothly synthesized from readily available 2-(1-alkynyl)-2-alkene-1-ones by DBU- or n-Bu(3)P catalyzed hetero-[4+2] cycloaddition reactions, in which 2-(1-alkynyl)-2-alkene-1-ones act as both heterodiene and heterodinenophile.

In the title mol-ecule, C(19)H(20)N(2)O(2), the cyclo-hexene ring adopts a sofa conformation, while the pyran ring adopts a flattened boat conformation. In the crystal, mol-ecules are linked by N-H⋯N and N-H⋯O hydrogen bonds, forming a two-dimensional network parallel to (010).

An environment friendly synthesis of 2-amino-3-cyano-4-aryl-7,7-dimethyl-5-oxo-4H-5,6,7,8-tetrahydrobenzo[b]pyran, 2aryl benzimidazole and 2-aryl-4, 5-dihydro-1H-imidazole derivatives using Mg-Al hydrotalcite as an efficient catalyst has been developed. The excellent efficiency of the catalyst can be attributed to its Lewis acidic sites which resulted in higher reaction yields for different sub...

The title compound, C(14)H(19)N(3)O(3), was synthesized by the reaction of 3-meth-oxy-propionitrile, tert-butyl bromo-acetate and eth-oxy-methyl-enemalononitrile. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into chains propagating along the b axis.

Synthesis of 4-(N,N- dimethylamino)-3-aryl-3-butene-2-one, ethyl-5-aryl-4-oxo-4H-pyran-2-carboxylate, ethyl-5-aryl-4-pyridones-2-carboxylate and 5-aryl-3-cyano-5-methyl-2-pyridones (aryl=3-thienyl, 2-furyl) are described.

A streamlined method for the enantioselective synthesis of 2-amino-4H-chromenes from readily available 2-alkyl-substituted phenols and active methylene compounds bearing a cyano group with up to 97% ee is presented. This reaction is a cascade procedure including manganese dioxide mediated C-H oxidation for the generation of o-quinone methides and bifunctional squaramide-catalyzed Michael additi...