Pyridine-3-carbaldehyde synthesis

Thieno[3,2-c]pyridine, 4,5,6,7-tetrahydro-biological activity, 4, 1015 Thieno[2,3-6]pyridine-2-carbaldehyde synthesis, 4, 1014... 

In addition to its use in the preparation of the square pyramidal Mo and W complexes 38 and 39, the Schiff base derived from pyridine carbaldehyde-(2) and S-(—)-a-phenyl ethyl amine54 was also used for the synthesis of optically active Co complexes of the tetrahedral type60. Unlike the Mo and W compounds, the separated Co diastereoisomers 40a, 40b one of which is shown in Scheme 20, are optically stable. The rigidity of the tetrahedral Co complexes and the nonrigidity of the square pyramidal Mo and W complexes give a further indication of the intramolecular character of the epimerization of 38 and 39. 

Hughes M, Prince RH, Wyeth P (1978) Metal ion function in alcohol dehydrogenases-II. The metal binding sites of pyridine carbaldehyde and N-benzyldihydronicotinamide. J Inorg Nucl Chem 40 713-718 Huskey WP, Schowen RL (1983) Reaction coordinate tunneling in hydride-transfer reactions. J Am Chem Soc 105 5704-5706 Inouye Y, Oda J, Baba N (1983) Reduction with chiral dihydropyridine reagents. In Morrison JD (ed) Asymmetric synthesis, vol 2. Academic Press, New York, p91... 

Amines While 3-pyrrolylaldehydes or ketones and 2-pyridyl ketones are transformed into rearranged and/or reduced McMurry products [50, 51], 2-pyrrolylalde-hydes or ketones and 3-benzoylpyridine can be coupled by low-valent titanium reagents, as shown by the synthesis of compounds 34, or 35 and 36, respectively [50-53] (Figure 6.6). Coupling of 3-pyridine carbaldehydes gives the dipyridyl... 

With the aid of a Knoevenagel condensation and a Staudinger reaction, 2-azidocyclopent-l-ene 1-carbaldehydes (195) can be converted into suitable products for a cyclopenta[b]pyridine synthesis [89JCS(P1)1369], as shown in Scheme 72. In order to bring the ester carbonyl function and the imino-phosphorane group into close proximity suitable for cyclization reactions, the 1,3-diene system 196 should possess the s-cis conformation. Furthermore, the exocyclic double bond should show a cis conformation. To achieve... 

A simple two-step synthesis of 4-arylthieno[3,2-c]pyridine-6-carboxylic acids has recently been presented by Eweiss (Scheme 74) (B-81MI31703). The condensation of thiophene-2-carbaldehyde with an N -aroylated a-amino acid yields a thienylidene azlactone (281) which on treatment with AICI3 is converted to a thieno[3,2-c]pyridine (283). A nitrilium ion (282) resulting from a vinyl-oxygen fission is probably involved as an intermediate. Sandberg s method already mentioned in the previous section has also been applied to the synthesis of thieno[3,2-c]pyridines (Scheme 75). 

The synthesis of quadridentate imine chelates usually requires the combination of two equivalents of the carbonyl compound and a diamine, as in the formation of complexes of ligands (6),17 18 (7)19 and (8).20,21 In similar fashion, thermodynamic template reactions allow the very effective synthesis of quinquedentate and sexadentate metal complexes of ligands such as (9),22 (10),23 (ll),24 (12)25 and (13).26 Condensation of 1,1,1-tris(aminomethyl)ethane with pyridine-2-carbaldehyde alone yields... 

Pyridine ring construction according to strategy P is based on the one-step formation of the C(4)-N(5) and C(7)-C(7a) bonds. For example, this approach provides the basis for the synthesis of the simplest isomeric dithienopyridines (1988CS281). The Stille cross-coupling reaction of 2-tributylstannyl-3-thiophene-carbaldehyde (256) with thienylcarbamates 115, 257, and 258 affords the target compounds 259-261, respectively, in different yields. 

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