Muehlstaedt, Manfred et al. published their research in Journal fuer Praktische Chemie (Leipzig) in 1970 | CAS: 13417-49-7

5,6-Dihydro-2H-pyran-3-carbaldehyde (cas: 13417-49-7) belongs to tetrahydropyran derivatives. Dihydropyrans and tetrahydropyrans are examples of cyclic ethers widespread in nature. The most notable anticancer agent, bryostatin, and eribulin are marine macrolides having intriguing tetrahydropyran and furan motif. HPLC of Formula: 13417-49-7

Mechanisms of the synthesis of pyridine basis by the gas-phase reaction of α,β-unsaturated aldehydes and ammonia was written by Muehlstaedt, Manfred;Uebel, Hans J.;Moll, Karl K.. And the article was included in Journal fuer Praktische Chemie (Leipzig) in 1970.HPLC of Formula: 13417-49-7 This article mentions the following:

Comparison between the products of the gas-phase reaction of NH3 with acrolein (I), crotonaldehyde (II), 3-formyl-5,6-dihydro-2H-pyran (III), 3-formyl-2,6-dimethyl-5,6-dihydro-2H-pyran (IV) and 2-formyl-3,4-dihydro-2H-pyran (V), with the formation of pyridines, indicated that III, IV and V were not intermediates in the reaction of I and II. No diene and aldol reaction was involved in the dimerization of I and II prior to the pyridine formation. The dimerizations seem to occur by α-β addition The reaction of I gave pyridine (VI) and 3-methylpyridine (VII), that of II 4-methyl-3-ethylpyridine, that of III VII, that of IV 2-methyl-5-ethylpyridine, and that of V gave VI and VII. In the experiment, the researchers used many compounds, for example, 5,6-Dihydro-2H-pyran-3-carbaldehyde (cas: 13417-49-7HPLC of Formula: 13417-49-7).

5,6-Dihydro-2H-pyran-3-carbaldehyde (cas: 13417-49-7) belongs to tetrahydropyran derivatives. Dihydropyrans and tetrahydropyrans are examples of cyclic ethers widespread in nature. The most notable anticancer agent, bryostatin, and eribulin are marine macrolides having intriguing tetrahydropyran and furan motif. HPLC of Formula: 13417-49-7

Referemce:
Tetrahydropyran – Wikipedia,
Tetrahydropyran – an overview | ScienceDirect Topics