Heterocycles from heterocycles. 1,3-Diaryl-4,5-imidazolidinediones from 1,3,5-triarylhexahydro-1,3,5-triazines and oxalyl chloride (original) (raw)
Chem. Heterocyclic Compds. 1998, 34, 69-72
Intramolecular cycloaddition of alkenes to nitrons is an efficient method of constructing hinged bridge systems [1][2][3][4]. Due to the high regio-and stereospecificity of formation of adducts and ease of transformation of their isoxazolidine fragment, this reaction was used in synthesis of complex structures, for example, the alkaloid luciduline [5], prostaglandins [6], secoishvaranol-12 sesquiterpene [3], and ambrosin [7].
Synthesis and reactivity of 2-dimethylamino-4-alkenyl-1, 3-oxazin-6-ones
Tetrahedron, 1989
The Vilsmeier-Haack reaction on 4-alkylideneisoxazolin+ones gives 2-dimethylamino-4-alkenyl-l,3-oxazin-6-ones. Depending on substitution pattern, from these oxazinones, cr-pyrones, 2-pyridones and pyridines may be obtained. The results confirm the thermal equilibrium between 2-dialkylamino-1,3-oxazin-6-ones, iminoketenes and vinylisocyanates. We recently reported on the synthesis and reactivity of 2_dialkylamino-1,3-oxazin-6-ones', and now report the synthesis and reactivity of L-dimethylamino-4-alkenyl-1,3-oxazin-6-ones 2, heterocycles which we have obtained by a Vilsmeier-Haack type reaction from 4-alkylideneisoxazolin+ones 1. The starting isoxazolones la-h have been reported (see Table I) while compounds li,j were prepared according to known methods 2,3 (see Experimental). As is well known for isoxazol-5-ones4, the 4-alkylideneisoxarol-5-ones may exist in CH and NH tautomeric forms5. When the Vilsmeier-Haack reaction is carried out on 4-alkylideneisoxarol-5-ones la-j, the corresponding 2-dimethylamino-4-alkenyl-l,3-oxatin-6-ones 2a-j are readily obtained in good yields (Scheme I and Table I). The reaction path is analogous with that previously reported for the Vilsmeier-Haack reaction of isoxazol-5-ones'. On compound lg the reaction has been carried out in DMF solution (see Experimental). In this case, besides the oxazinone 29, the derivative 3 has been obtained. The structure of compound 3 was assigned on the basis of single-crystal X-ray diffraction analysis and Figure I shows the molecular shape and numbering scheme. 74x5 3 (15) CH2C12-MeOH (1OO:l) 171-172' lh3 Ph Ma COOU E-2h (51) CH2C12-Et20 (JO:11 122-123' 3 Z-2h (28) 116-117" lig Me Me COOEt E-21 (82) hexane-Et20 (3:l) oil 3 Z-21 (8) 64-65' ljg n-C3H7 Be COOMe E-23 (80) CH2C12-Et20 (3O:l) 74-75d 3 Z-23 (14) oil "Et20-hexane. bEt2O. 'CH2C12-Et20. dhexane. e This reaction has been carried out at 8O'C in DMF. 2-Dimethylamino-4-alkenyI-1,3-oxazin-6-ones E. M. BECCALLI et al. aldehydooxazinones E-6b,c (Table III). WPyrone 7e from E-6e A solution of the aldehydooxazinone E-6e (1 mmol) in CH2Cl2 (50 mL) was irradiated (Pyrex vessel) with a high pressure Hg lamp (Philips HPK 125W) for 30 min. The residue from the solvent evaporation was purified by column chromatography to give pure a-pyrone 7e (Table III). Pyridines 8b,c,e from aldehydooxazinones E-6b,c,e. General Procedure The aldehydooxazinone 6 (0.5 mmol) was dissolved in dioxane (15 mL), and then H20 (5 ml) was added. The reaction mixture was heated under reflux for 3h. The residue from the SOlVent evaporation was purified by column chromatography to give pure compounds Bb,c,e (Table IV). 2-Pyridones 9h-j by thermal reaction of oxazinones E-2h-j. General Procedure The oxazinone 2 (300 mg) was dissolved in anhydrous dioxane (5 mL) and the reaction was carried out in a sealed tube at 115°C for 72h. After solvent evaporation, the residue was crystallized (for the crystallization solvents see Table V) to give pure 9h (67%), 9i (64%) and 9j (57%). 2-Pyridones lOh-j by reaction with H20 of the oxazinone Z-2h-j. General Procedure The oxazinone 2 (200 mg) was dissolv:d in dioxane (4 mL) and then H20 (2 mL) was added. The reaction was carried out at 110°C for 15h in a sealed tube. After solvent evaporation, the residue was crystallized to give pure pyridones lOh-j (Table V). 2-Pyridones 9h-j and lOh-j by reaction with H,O of the oxazinones E-Eh-j. General Procedure The reactions were carried out as described above and after 15h at 110°C pure pyridones 9h-j and lOh-j were obtained after columnu chromatography (Table V). X-ray Structure Oetermination. All single crystal X-ray measurements were performed on a Nonius CAD-4 diffractometer. The used radiation was graphite monochramated MoKa, n=O.71069A. The structures were solved by direct methods (program MULTAN14). The refinements were made by minimizing the function C~~(lP,IP, l)2 with weights w=410/[02(10)+0.000412,]. Crystal data and some details of data COlleCtiOn and of full-matrix least-squares refinement are given in Table VII. (A) oxazinone 3 (XR-1). Single crystals of XR-1 suitable for X-ray difraction study were grown from methylene chloride. The compound co-crystallizes with the solvent and the crystal formula is C20H21N303.1/6CH2C12 with formula weight 365.6. The molecules, essentially by means of eleCtrOStatiC interactions involving the nitrogen atoms, the oxygen atom bonded to the oxatine ring and the carbon atoms of the dimethylimido group, make layers parallel to the c axis. Between couple of layers, around a 3 crystallographic point, a hole ,is formed that include solvent. Such a structure is quite stable a do not change by changing the Table VI. Spectral data of new compounds. Product IR (cm-') 'H-NMR(CDC13I 6. J(
Keywords: cyanoselenoacetamide, N-methylmorpholinium 1,4,5,6,7,8-hexahydroquinoline-2-selenolates, multicomponent cyclocondensation, Hantzsch synthesis.
Chem. Heterocyclic Compds. 2009, 45, 308-316
were obtained for the first time from 8-aminoquinolines using the Povarov reaction. Various oxidizing agents were shown to effect the elimination of the substituent at C(4) with subsequent aromatization of the tetrahydroquinoline fragment.
Liebigs Annalen der Chemie, 1985
A synthesis of N-benzylidene-2-furanamines 8 by means of cyanide addition to acylchalcones 2, followed by piperidine-catalyzed cyclization in the presence of an aldehyde is reported. The 2-pyrrolones 4 are formed together with the compounds 8. In the absence of an aldehyde no furan is obtained. The intermediate 2-ary1-3-benzoyl-4-0~0-4-phenylbutanenitriles 3 are easily isolated. The N-benzylidene-2-furanamines 9 are obtained from the oxonitriles 5.