Synthesis and Structural Study of 3,4‐Dihydro‐2(1 H )‐pyridones and Isoxazolo[5,4‐ b ]pyridin‐6(7 H )‐ones

Abstract

A series of isoxazolo [5,4-b]pyridin-6(7H)-ones (8) have been prepared with a high stereochemical control from the novel 3,4-dihydro-2(1H)-pyridones (7) by reaction with hydroxylamine hydrochloride and subsequent 5-endo-trig cyclization. A structural study by X-ray analyses and theoretical

Synthesis and structural study of new highly lipophilic 1,4-dihydropyridines

“…In previous works we have widely used theoretical calculations for determining the structural and conformational features of 1,4-DHPs and 3,4-dihydropyridone derivatives and we have demonstrated that ab initio and semiempirical calculations (at the AM1 level) reproduce adequately the geometry of this type of compound, taking into account the X-ray diffraction studies. [24][25][26][27] All compounds were calculated using a semiempirical AM1 method. In the case of model compounds 4k, 4n and 4o calculations were performed using ab initio HF/6-31G* and DFT (B3LYP/6-31G*) methods for the sake of comparison.…”

“…s, 9 Â CH 2 ), 0.85 (3H, t, J ¼ 6.4 Hz, CH 3 ); 13 C NMR (DMSO-d 6 ), d: 167.4 (C5-CQO), 166.9 (C3-CQO), 164.9 (C1 0 ), 149.1 (C3 0 ), 146.1, 146.0 (C2, C6); 135.5 (C5 0 ), 121.4, 121.2 (C4 0 , C6 0 ), 100.3 (C3) 100.2 (C5), 62.9 (OCH 2 ), 50.0 (OCH 3 ), 41.1 (C4), 31.3 (CH 2 ), 29.0 (2 Â CH 2 ), 28.9 (CH 2 ), 28.7 (CH 2 ), 28.6 (2 Â CH 2 ), 28.2 (OCH 2 CH 2 ), 25.5 (CH 2 ), 22.1 (CH 2 ), 18.3 (2 Â CH 3 ), 13.9 (CH 2 CH 3 ); MS-EI m/z(%) 456 (M 1 , 1), 378 (100), 271 (4), 210 (41), 178 (5) 3,5-dicarboxylate (4c). Obtained from 1g, 2a and 3a in 65% yield, mp: 167-169 1C, IR (KBr) n 3260 (NH), 2225 (CN), 1690 (CQO), 1628 and 1593 (CQC); 1 H NMR (DMSOd 6 ), d: 8.90 (1H, s, NH), 8.40 (1H, d, J ¼ 4.7 Hz, H3 0 ), 7.58 (1H, td, J ¼ 7.7 Hz, J ¼ 1.8 Hz, H5 0 ), 7.18 (1H, d, J ¼ 7.7 Hz, H6 0 ), 7.11 (1H, dd, J ¼ 7.7 Hz, J ¼ 4.7 Hz, H4 0 ), 5.01 (1H, s, H4), 4.14 (2H, t, J ¼ 6.0 Hz, OCH 2 ), 3.53 (3H, s, OCH 3 ), 2.83 (2H, m, CH 2 CN), 2.25 (3H, s, CH 3 -C2), 2.24 (3H, s, CH 3 -C6); 13 C NMR (DMSO-d 6 ), d: 167.4 (C5-CQO), 166.5 (C3-CQO), 164.7 (C1 0 ), 149.1 (C3 0 ), 147.2, 146.1 (C2, C6), 135.8 (C5 0 ), 121.6 (C6 0 ), 121.4 (C4 0 ), 118.8 (CN), 100.5 (C5), 99.5 (C3), 58.4 (OCH 2 ), 50.6 (OCH 3 ), 41.0 (C4), 18.6 (CH 3 -C2), 18.3 (CH 3 -C6), 17.5 (CH 2 -CN); MS-EI m/z(%) 341 (M 1 , 2), 263 (100), 210 (26), 178 (5). Anal.…”

Synthesis of dihydropyranones and dihydropyrano[2,3-d][1,3]dioxine-diones by cyclization reaction of Meldrum’s acid with arylaldehydes and 1,3-dicarbonyls under thermal and ultrasound irradiation

“…[17][18][19][20][21][22][23] Our literature survey revealed that there are some examples in the synthesis of 3,4-dihydro-α-pyranones by several groups. [24][25][26][27][28][29][30][31] But, little efforts have been paid to the synthesis of dihydropyranone and dihydropyrano [2,3-d] [1,3]dioxine-dione derivatives. [32][33][34][35][36][37][38] To make the synthesis of this kind of compound in a more efficient and in continuation of our studies on one-pot multi-component reactions, [39][40][41] we report here a one-pot three-component reaction of Meldrum's acid, arylaldehydes, and various 1,3-dicarbonyls in the presence of KOH as a base in H2O:EtOH under thermal and ultrasound irradiation.…”

1H and 13C spectral assignment of 2(1H)‐pyridone derivatives

“…12,13 In connection with our studies of novel calcium channel modulators, we have previously described the synthesis and conformational study of 5-alkoxycarbonyl-6-methyl-3,4-dihydropyridines 14 and 5-acetyl-4-aryl-3,4-dihydro-6-methyl-2(1H)-pyridones. 15 Recently we also reported a solid-phase synthesis method 16 and a solventfree synthesis under microwave irradiation of 5-alkoxycarbonyl-6-methyl-3,4-dihydropyridones. 17 We have also reported the mass spectrometric behaviour of substituted 3,4-dihydro-2(1H)-pyridin-2-ones by electrospray ionization and ion-trap fragmentation methods.…”