5-ethylpyridine-2-carbaldehyde(SALTDATA: FREE)

As depicted in step f of Scheme 1, MnO2 was prepared freshly bysimultaneously adding a solution of MnSO4 hydrate (14.5 g, 0.09 molin 25 mL water) and NaOH (7.6 g, 2.21 mol in 20 mL water) to awarm solution of KMnO4 (15.5 g, 0.10 mol in 100 mL water), refluxingthe mixture for 6 h, filtered and dried under reduced pressure.5-Ethylpyridin-2-yl-methanol (12.82 g, 93.4 mmol) was dissolved inchloroform and given to the dried MnO2 (16.24 g, 186.8 mmol). Themixture was refluxed in an ultrasonic bath for 5 days, filtered andpurified with column chromatography using a mixture petroleumether and ethyl acetate (4:1) on silica gel to give the product as a brightyellow liquid in 61percent yield. 1H NMR (500MHz, CDCl3): δ=10.03 (s, 1H, CHO), 8.60 (d, 4J(H, H) = 1.9 Hz, H-6), 7.87 (d, 3J(H, H) = 8.0 Hz, H-3), 7.70–7.63 (m, H-4), 2.73 (q, 3J(H, H) = 7.6 Hz, 2H, CH2CH3), 1.28(t, 3J(H, H) = 7.6 Hz, 3H, CH2CH3). 13C NMR (126 MHz, CDCl3): δ =193.30 (CHO), 151.06 (C-2), 150.18 (C-6), 144.67 (C-5), 136.28 (C-4), 121.72 (C-3), 26.43 (CH2CH3), 15.02 (CH2CH3).The latter was dissolved in 100 ml of trichloromethane, mixed with 8 g of manganese dioxide and refluxed for 2 hours. The solution was filtered hot and the filtrate rotated in. 4 g of 5-ethyl-pyridine-2-aldehyde were obtained.General procedure: General method: The Schiff bases were obtained by adding an ethanolic solution of the hydrazinyl component to the solution of the keto component in equimolar amounts, refluxing the mixture in the presence of catalytic amounts of acid. If not indicated otherwise, purification was carried out by recrystallization. Carbazides were prepared by adding an equimolar amount of hydrazine to the methanolic solution of the respective isothiocyanate [53]. For the picolinylidene derivatives with ethyl group in 5-position of the pyridine moiety (2e, 2k), 5-Ethylpicolinaldehyde was prepared from 5-ethyl-2-methyl-pyridine as reported previously [13, 115]. The reaction of General procedure: General method: The Schiff bases were obtained by adding an ethanolic solution of the hydrazinyl component to the solution of the keto component in equimolar amounts, refluxing the mixture in the presence of catalytic amounts of acid. If not indicated otherwise, purification was carried out by recrystallization. Carbazides were prepared by adding an equimolar amount of hydrazine to the methanolic solution of the respective isothiocyanate [53]. For the picolinylidene derivatives with ethyl group in 5-position of the pyridine moiety (2e, 2k), 5-Ethylpicolinaldehyde was prepared from 5-ethyl-2-methyl-pyridine as reported previously [13, 115]. The reaction of General procedure: General method: The Schiff bases were obtained by adding an ethanolic solution of the hydrazinyl component to the solution of the keto component in equimolar amounts, refluxing the mixture in the presence of catalytic amounts of acid. If not indicated otherwise, purification was carried out by recrystallization. Carbazides were prepared by adding an equimolar amount of hydrazine to the methanolic solution of the respective isothiocyanate [53]. For the picolinylidene derivatives with ethyl group in 5-position of the pyridine moiety (2e, 2k), 5-Ethylpicolinaldehyde was prepared from 5-ethyl-2-methyl-pyridine as reported previously [13, 115]. The reaction of 5-ethyl-picolinaldehyde (200mg, 1.48mmol) with 2-hydrazinobenzothiazole (244.5mg, 1.480mmol) in ethanolic solution under acetic acid catalysis resulted in cream-colored precipitate, which delivered the pure product in 46% yield (192.2mg, 0.681mmol) after recrystallization. 1H NMR (500MHz, DMSO-d6): delta=12.41 (bs, 1H), 8.46 (dd, 1H, 5J(H, H)=0.6Hz, 4J(H, H)=2.1Hz), 8.13 (s, 1H), 7.84 (d, 1H, 3J(H, H)=7.9Hz), 7.79 (d, 1H, 3J(H, H)=7.9Hz), 7.73 (ddd, 1H, 3J(H, H)=0.5Hz, 3J(H, H)=2.1Hz, 3J(H, H)=8.2Hz), 7.48 (d, H, 3J(H, H)=4.8Hz), 7.31 (td, 1H, 3J(H, H)=1.3Hz, 3J(H, H)=8.0Hz), 7.17-7.10 (sm, 1H), 2.66 (q, 2H, 3J(H, H)=7.7Hz), 1.21 (t, 3H, 3J(H, H)=7.7Hz). 13C NMR (126MHz, DMSO-d6): 167.0, 150.8, 148.9, 139.4, 136.0, 126.0, 121.8, 121.5, 119.0, 25.2, 15.1 - the signals for HC=N, C-3, C-3'a, C-7'a were not visible. Anal. Calcd. for C15H14N4S: C: 63.80; H: 5.00; N: 19.84. Found: C: 63.47; H: 4.886; N: 19.81

Molecular Weight:135.16
XLogP3:1.4
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:2
Exact Mass:135.068413911
Monoisotopic Mass:135.068413911
Topological Polar Surface Area:30
Heavy Atom Count:10
Complexity:114
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes