2,4-Dinitrofenilhidrazonas

1186

J. Org. Chem. 1985,50, 1186-1189
mol 76

by the NMR analysis, were as follows:
fraction
I 8

wt.

g

8a
0

12
100

0.25 0.62
0.41

9
10 11

12

0.29 0.25 0.21

5 62 93
100 100

95
38 I 0 0

Fraction 7, a liquid, was pure 5-ethyl-3-phenyl-l,2,4-oxadiazole (12):16 m / e 174.2, calcd M+ = 174.1; 'H NMR (CDC13)6 1.36 (t, J = 7.6 Hz, 3 H, CH3),2.88 ( q , J =7.6, 2 H, CHz),7.42 (m, 3 H, Ar H), 8.10 (m, 2 H, Ar H); 13CNMR (CDClJ 6 10.5 (CH,), 20.0 (CHJ, 126.8,127.1,128.5, 130.7,lB.O (C-3),180.4 (C-5);IR (neat) 3060, 3015, 2980, 2935, 2875, (all C-H), 1591,1570, 1475, 1445, 1360, 1342, 1305, 902, 780, 714, 690 cm-l. Fractions 11 and 12 both formed white crystals of 5-methyl3-phenyl-1,2,4-oxadiazole identical in mp, mmp, 'H and 13C (8a) NMR, and IR with anauthentic sample.1° Fractions 7-12, comprising 88% recovery by weight of the original crude product, represented a 41% yield of 8a and a 32% yield of 12, for a total yield of 73% of combined oxadiazoles. B. Reaction of Benzonitrile, Nitroethane, Ammonium Propionate, and Propionic Acid. In a parallel experiment employing 2.00 g (19 mmol) of benzonitrile, 14.2 g (156 mmol) of ammonium propionate,52.3 g (700 mmol) of nitroethane, and 24.8 g (335 " 1 0) of propionic acid, refluxed (N,) 72 h, there was obtained a 20%. yield of 8a and a 34% yield of 12;total yield 54% of oxadiazoles. Reaction of 1-Nitropropane with Ammonium Acetate in Acetic Acid. A. Formation of Propionic Acid. A solution of 14.2 g (184 mmol) of ammonium acetate in 62.5 g (702 mmol) of 1-nitropropane and 25 mL (436 mmol) ofacetic acid was refluxed under Nz for 72 h. The initially colorless solution gradually
(15) Morrocchi, S.; Ricca, A.; Velo, L. Tetrahedron Lett. 1967, 331.

turned to a deep amber-yellow. Gas chromatographic analysis of the crude reaction mixture run isothermally at 30 "C on the HP 5880A capillary column showed the following fractions [retention time, (compound) relative area]: 0.75 min (HOAc)1.09; 1.32 min (1-nitropropane) 3.97; 1.67 min (propionic acid) 1.39; 2.49 min (unknown) 0.74; 3.27 min (unknown) 0.86. Since all of the propionic acid must have originated from the 1-nitropropane, the yield of propionic acid was 26%. B. Trapping of Hydroxylamine. A mixture of 11.11g (61 "01) of benzophenone, 10.45g (136 "1 0) of ammonium acetate, 17.8 g (200 mmol) of 1-nitropropane, and 26.2 g(436 mmol) of acetic acid was refluxed under N2 for 10 h. The resulting pale yellow solution was cooled and then diluted with 150 mL of water to yield a white precipitate, which was thoroughly washed with HzO and air-dried. One recrystallization from 95% ethanol gives 7.17 g (60% yield) of benzophenone oxime, mp 137-139 "C. One more crystallization gave pure oxime, mp 139.5-141 "C, identical (mp,mmp, and IR) with an authentic sample16

Acknowledgment. We are grateful to the Department of Chemistry of Lehigh University for support of this work and also thank Dr. Uli Hacksell for helpful discussions.
Registry No. la, 100-52-7; lb, 93-02-7; 4a, 100-47-0; 4b, 5312-97-0; Sa, 1198-98-7; Sb, 95124-65-5; 8c, 69792-78-5; 8d, 95124-66-6; 8e, 81386-30-3; Sf, 95124-67-7; 8g, 95124-68-8; 9,1199-00-4;12, 10364-68-8;benzamidoxime, 613-92-3; acetamidoxime, 22059-22-9; 0-benzoylacetamidoxine, 22046-72-6; 4methylbenzaldehyde, 104-87-0; ammonium propionate, 17496-08-1; ammonium acetate, 631-61-8; nitroethane, 79-24-3; benzoyl chloride, 98-88-4; 2,4-dichlorobenzaldehyde, 874-42-0; 3-chlorobenzaldehyde, 587-04-2;3,5-dimethoxybenzaldehyde, 7311-34-4; 4-formylbenzoic acid, 619-66-9; 1-nitropropane,108-03-2;benzophenone, 119-61-9;benzophenone oxime, 574-66-3.
(16) Lackman, A. 'Organic Syntheses"; Wiley: New York, 1943; Collect. Vol. 11, p 70.

2,4-Dinitrophenylhydrazones: A Modified Method for the Preparation of These Derivatives and an Explanation of Previous Conflicting Results
Mohammad Behforouz,* Joseph L. Bolan, and Michael S. Flynt'
Department of Chemistry, Ball State University,...