Synthesis of Pyrrolo[2,1- c ][1,4]oxazine-1,6,7-triones by the Reaction of 3-Methylenemorpholin-2-ones with Oxalyl Chlor
- PDF / 729,810 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 25 Downloads / 149 Views
hesis of Pyrrolo[2,1-c][1,4]oxazine-1,6,7-triones by the Reaction of 3-Methylenemorpholin-2-ones with Oxalyl Chloride N. A. Tret’yakova, M. V. Dmitrieva, and A. N. Maslivetsa,* a
Perm State University, Perm, 614990 Russia *e-mail: [email protected]
Received March 17, 2020; revised March 26, 2020; accepted March 30, 2020
Abstract—(Z)-3-(2-Aryl-2-oxoethylidene)morpholin-2-ones were synthesized by the reaction of aroylpyruvic acids with ethanolamine or 2-propanolamine. The products reacted with oxalyl chloride to form 8-aroyl-3,4dihydropyrrolo[2,1-c][1,4]oxazin-1,6,7(1H)-triones. Keywords: enaminoketone, 3-methylenemorpholin-2-one, pyrroloxazinetrione, oxalyl chloride, hetareno[e]pyrrole, 4-hetarylfurandione, X-ray diffraction
DOI: 10.1134/S1070428020080060 Heterocyclic enaminoketones react with oxalyl chloride to form hetareno[e]pyrrole-2,3-diones [1–13] or 4-heterylfuran-2,3-diones [14] or their mixture [15]. To obtain more evidence which would make it possible to predict what of the two mentioned directions would be realized, we synthesized substituted 3-methylenemorpholin-2-ones, representatives of a new class of heterocyclic enaminoketones, and studied their reaction with oxalyl chloride. The structure of the substituted morpholinones seems to be borderline for the realization of one of the alternative directions of the reaction with oxalyl chloride Heating aroylpyruvic acids 1a–1f with ethanolamine 2a or 2-propanolamine 2b in the presence of acetic acid in a 1 : 1 : 1 ratio in toluene with a Dean–Stark trap for 4–8 h (until water no longer evolved) gave (Z)-3-(2-aryl2-oxoethylidene)morpholin-2-ones 3a–3k (Scheme 1). The structure of compounds 3a, 3e, and 3i was confirmed by X-ray diffraction (XRD) analysis. Compounds 3a–3c were described earlier [16], which compounds 3d–3k were synthesized for the first time. Under the conditions of synthesis of compounds 3a–3c described in [16], specifically heating under reflux in 1,4-dioxane for 1–1.5 h) [16], we faced strong tarring of the reaction mixture and lower yields of products. Compounds 3a–3k are high-melting light yellow crystalline substances soluble in DMSO, DMF, acetone, ethyl acetate, chloroform, and 1,4-dioxane, sparingly
soluble in aromatic hydrocarbons, and insoluble in alkanes and water. The IR spectra of compounds 3a–3k contain absorption bands of the NH bond (3198–3247 cm–1, broad), lactam C1=O group (1730–1744 cm–1), and C=O group of the aroyl fragment (1615–1623 cm–1). The 1H NMR spectra of compounds 3a–3k display, along with proton signals of the methylene groups of the morpholine ring and the aromatic rings and their substituents, a singlet of the methine proton (6.50– 6.56 ppm) and a singlet of the NH proton (10.48– 10.66 ppm). The 13C NMR spectra of compounds 3a–3k show characteristic signals of the ketone carbonyl of the aroyl fragment (186.7–189.1 ppm) and lactam C1=O group (160.1–160.8 ppm). The reaction of compounds 3a–3k with oxalyl chloride under the conditions usual for the synthesis of five-membered dioxaheterocycles (heating in anhydrous chlor
Data Loading...
