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Molbank 2002, 2002(1), M277; https://doi.org/10.3390/M277

Short Note
Chiral Methyl 7,8,9-Trichloro-6,7,8,9-tetrahydro-5-oxopyrido-[2,3-a]indolizine-10-carboxylates (OPIC)
1
Faculté des Sciences Dhar El Mehraz, Departement de Chimie, 30000 Fès, Morocco
2
Faculté des Sciences d'Oujda, Departement de Chimie, 60000 Oujda, Morocco
*
Author to whom correspondence should be addressed.
Received: 19 April 2002 / Accepted: 4 May 2002 / Published: 16 February 2003
Keywords:
Indolizine - Oxopyrido- Chlorination - Cycloacylation- OPIC
Molbank 2002 m277 i001
The 3,3'-dihydoxycarbonyl-2,2'-bipyridine acid 1 used for the preparation of diastereoisomeric compounds 2a-b has been obtained by described method of Blau [1].
Procedure A: To 10 mL of clean thionyl chloride (new bottle without further distillation), were added 600 mg (2.5 mmol) of 3,3'-dihydroxycarbonyl-2,2'-bipyridine 1 and the mixture was refluxed for 5 h. Then the excess of SOCl2 was removed under vacuum to leave an unstable yellow residue [1]. 20 mL of toluene and then 1 mL of MeOH were added and the solution was heated at reflux for 3 h. 40 mL of chloroform were added and the organic phase was washed with a cooled solution of sodium hydrogen carbonate (2.5%), and then dried on sodium sulfate. The crude product was chromatographed on silica column. Only compound 3 was obtained as product of reaction (55-60%); the rest is the unreacted stating material 1.
Procedure B: When we used an old bottle of SOCl2, in the same conditions (procedure A), three white solids were successively obtained: a mixture of petroleum ether/dichloromethane 10/90 eluted first compound 2a (310 mg, 31 %), and then in the ratio 5/95 derivative 2b (70 mg, 7%) was recovered; and finally with ether/acetone 40/60, the diester 3 (450 mg, 52%) was eluted, which has been described elsewhere [2].
Molbank 2002 m277 i002
Compound 2a: methyl (7S,8R,9S)-7,8,9-trichloro-5-oxo-5,7,8,9-tetrahydropyrido-[2,3-a] indolizine-10-carboxylate (Labelling used for NMR assignments)
m.p. = 121-122 °C; Analysis Calc. (Found) for C13H9N2O3Cl3: C 44.94 (44.98), H 2.59 (2.63), N 8.06 (7.99); Mass spectrum : m/z = 347.0 (Calc. for C13H9N2O3Cl3: 346.60); IR (KBr) n cm-1: 1744 (C=O, s), 1717 (C=O, s), 1601,1581 (C=C, w), 1434 (C=N, m), 1297 (C-O, w); 1H NMR (250.14 MHz; CDCl3) d ppm: 8.9 (dd, H2, 3JH2-H3 = 4.9 Hz, 4JH2-H4 = 1.6 Hz), 8.2 (dd, 1 H, H4,3JH4-H3 = 7.8 Hz,4JH4-H2 = 1.6 Hz), 7.53 (dd, 1 H, H3, 3JH3-H4 = 7.8 Hz, 3JH3-H2 = 4.9 Hz), 6.49 (dd, 1 H, H7, 3JH7-H8 = 1.33 Hz, 4JH7-H9 = 2.1 Hz), 5.35 (t, 1 H, H8, 3JH8-H7 = 1.33 Hz, 3JH8-H9 = 1.33 Hz), 5.03 (dd, 1 H, H9, 3JH9-H8 = 1.33 Hz,4JH7-H9 = 2.1 Hz), 4.0 (s, 3 H, CH3).
Compound 2b: methyl (7R,8R,9S)-7,8,9-trichloro-5-oxo-5,7,8,9-tetrahydropyrido-[2,3-a]-indolizine-10-carboxylate
Mass spectrum : m/z = 347.0 (Calc. for C13H9N2O3Cl3: 346.60); 1H NMR (200.131 MHz; CDCl3) d ppm: 8.86 (dd, 1 H, H2, 3JH2-H3 = 4.9 Hz, 4JH2-H4 = 1.6 Hz), 8.14 (dd, 1 H, H4, 3JH4-H3 = 7.8 Hz, 4JH4-H2 = 1.6 Hz), 7.48 (dd, 1 H, H3, 3JH3-H4 = 7.8 Hz, 3JH3-H2 = 4.9 Hz), 6.47 (d,1 H, H8, 3JH8-H9 = 3 Hz), 5.26 (d, 1 H, H10, 3JH10-H9 = 9.8 Hz), 4.52 (dd, 1 H, H9, 3JH9-H8 = 3.05 Hz, 3JH9-H10 = 9.75 Hz), 3.96 (s, 3H, CH3).

Supplementary Materials

Supplementary File 1Supplementary File 2Supplementary File 3Supplementary File 4Supplementary File 5Supplementary File 6

Acknowledgement

This work was supported by the Grants of Ministry of Education of Morocco Kingdom (PROTARS No. P1T2/27), France - Maroc collaboration (AI N 98/ 160/ SM). We are indebted to Prof. P. Dixneuf and H. Le Bozec for further development of this new heterocyclic chemistry.

References and Notes

  1. Blau, F. Ber. Dtsch. Chem. Ges. 1888, 21, 1077.
  2. Ben-Hadda, T.; Sam, N.; Le Bozec, H.; Dixneuf, P. H. Inorg. Chem. Com 1999, 2, 460.
  • Sample Availability: Available from the authors
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