108 J . Org. Chem., Vol. 39, No. I , 1974 the methine proton adjacent to the oxygen atom of 4 in KODD20 solution was found to be a doublet (J1 = 1.8 Hz) of quartets (Jz = 6.5 Hz). As a result of a decoupling experiment, J1 was found to correspond to the vicinal coupling between the two methine groups in agreement with the assignment of P-adduct structure t o 4. Analogously to the case of 2, the 3,5-dinitrobenzoate of 4 was obtained in 83% yield: mp 140-143" from methanol; ir (KBr) 1781 (SI, 1721 (s), 1550 (s), 1347 (s), 14292 (s), 1179 (s), 1120 cm-1 (m); nmr (CDC13) 6 1.51 (d, 3 H ) , 1.73 (s, 6 H ) , 2.3-3.1 (m, 3 HI, 4.80 (dq, 51 = 6.6, JZ = 2.8 Hz, 1H), 9.0-9.3 (m, 3 H ) . Anal. Calcd for C ~ H 1 6 0 8 N 2 C, : 51.14; H , 4.58; N, 7.95. Found: C, 51.12; H, 4.57; K,8.09. Isopropyl Alcohol Adducts of 5,6-Dihydro-6-methyl-2Hpyran-2-one. By the use of silica gel chromqtography (eluent, benzene-ethyl acetate mixture in 1:l ratio by v/v), two adducts were separated from the reaction mixture, 7b (yield 36%) and 6a (yield 16%). On the basis of both the spectroscopic and chemical evidences described below, 6a and 7b were concluded to he 6- and y-lactone, respectively. A. y-Lactone 7b was a viscous liquid: ir (neat) 3440 (broad), 1760 (broad), 1273 cm-I (broad); nmr (in benzene) d 0.95 (s, 3 H), 1.22 (s, 3 H ) , 1.10 (d, J = 6.2 Hz, 3 H), 0.8-2.8 ( m , 5 H), 2.99 (s, 1 H), 3.2-3.8 (m, 1 H ) ; nmr (CDC13) 6 1.24 (d, J = 6.2 Hz, 3 H ) , 1.25 (s, 3 H), 1.45 (s, 3 H), 1.3-1.7 (m, 2 H ) , 1.7-3.0 (m, 3 H ) , 2.74 (s, 1 H), 3.5-4.1 (m, 1 H ) . The frequency of the carbonyl absorption band corresponds to those of saturated y-lactones. As to the nmr spectra, we observe two singlet signals which correspond to three protons, respectively: the difference in chemical shifts between the two signals is as large as 0.2 ppm in both benzene and deuteriochloroform. It is suggested then that there are two highly nonequivalent methyl groups. In addition, the benzeneinduced shifts for these singlets are much larger than that for the doublet (1.10 ppm in benzene) which is assigned to the methyl protons coupled to an adjacent methine proton. These facts are in good agreement with the proposed structure 7b, but not with 6b. Finally, the hydroxyl proton signal of 7b splits into a doublet ( J = 4.9 Hz), when the acetone solution is cooled down below -10". Therefore, a secondary hydroxyl group must be involved in 7b. The structure of 7b is thus deduced. The corresponding 3,5-dinitrobenzoate was obtained by the usual method in 93% yield: m p 180-181" from methanol; ir (KBr) 1767 (s), 1756 (shoulder), 1726 (s), 1544 (s), 1347 (s), 1279 (s), 1173 (m), 1133 c m - I ( m ) ; nmr (CDC13) 6 1.31 (s, 3 HI, 1.48 (s, 3 H), 1.51 (d, J = 6.0 Hz, 3 H), 1.2-2.9 (m, 5 H), 5.0-5.5 (m, 1H), 9.0-9.3 (m, 3 H). Anal. Calcd for C16H1808N2: C, 52.47; H , 4.95; X, 7.65. Found: C, 52.52; H , 4.94; N,7.45. B. &Lactone 6a was a viscous liquid: ir (neat) 3510 (broad), 1729 (s), 1254 cm-' (broad); nmr (in benzene) 6 0.98 (5, 6 H), 1.09 (d, J = 6.2 Hz, 3 H), 0.9-2.5 (m, 5 H ) , 2.46 (s, 1 H), 3.5-4.2 (m, 1 H). The proton signals of 6a in CDC13 gradually disappear and new sets of signals arise in return. Then a benzene solution of 6a was prepared and a very small amount of dry hydrogen chloride was bubbled into the solution. This treatment completed the transformation from 6a into the new compound 7a, which was easily recovered by purging the solvent with a nitrogen stream. C. y-Lactone 7a was recrystallized from n-hexane-benzene mixture: m p 122.5-123.5"; ir (KBr) 3250 (shoulder), 3400 (broad), 1761 (s), 1747 (shoulder), 1275 (m), 1262 (s), 1122 (s), 1103 cm-I (s); nmr (CDCl3) 6 1.23 (d, J = 6.3 Hz, 3 H ) , 1.25 (s, 3 HI, 1.45 (s, 3 H ) , 1.3-1.7 (m, 2 H ) , 1.7-2.9 (m, 3 H ) , 2.68 (s, 1 H ) , 3.38 (tq, J1 = Jz = 6.3 Hz, 1 H ) . The structure of multiplets with a pair of prominent peaks around 2.5 ppm is clearly different from the corresponding multiplets of 7b in which a single, sharp peak is observed at 2.5 ppm. The hydroxyl proton signal of 7a also splits into a doublet ( J = 4.8 Hz) when the acetone solution is cooled down. In vpc analyses, there is a small hut clear difference in retention time between 7a and 7b so that a pair of slightly overlapping peaks are observed when both of the compounds are injected into the column at the same time. Anal. Calcd for C9H1603: C, 62.76; H, 9.37. Found: C, 62.88; H , 9.66. Registry No. 1, 497-23-4; 2, 42867-48-1; 2 3,5-dinitrobenzoate, 42867-49-2; 3, 591-11-7; 4, 42867-50-5; 4 3,5-dinitrobenzoate, 42867-51-6; 5 , 108-54-3; 6a, 42867-52-7; 6b, 42867-53-8; 7a, 4286754.9; 7b, 42867-55-0; 7 3,5-dinitrobenzoate, 42867-56-1; isopropyl alcohol, 67-63-0; 3,5-dinitrobenzoyl chloride, 99-33-2.
References and Notes ( 1 ) Contribution No. 314 from t h e Department of Organic Synthesis,
Notes Faculty of Engineering, Kyushu University. T h e work was supported in part by a grant from the Ministry of Education. (a) P. de Mayo, J.-P. Pete, and M . Tchur, Can. J. Chem., 46, 2535 (1968); ( b ) P. Bladon and I . A. Williams, J. Chem. SOC. C, 2032 (1967); (c) M. Pfau, R. Duiou, and M . Vilkas, C. R. Acad. Sci., 254, 1817 (1962); ( d ) R . Dulou, M . Vilkas, and M . Pfau, ibid., 249, 429 (1 959). (a) M. Pfau, R. Dulou, and M . Vilkas, C. R. Acad. Sci., 251, 2186 (1960); (b) G. 0. Schenck and R. Steinmetz, Naturwissenschaften, 47,514 (1960). K. Ohga and T. Matsuo, Bull. Chem. SOC.Jap., 43, 3505 (1970). J . Thiele, R. Tischbein, and E. Lossow, Justus Liebigs Ann. Chem., 319,180 (1901). R. K u h n and D. Jerchel, Chem. Ber., 76,413 (1943)
Synthesis of Hydroxycitronellal. Hydration and Subsequent Hydrolysis of Imines, Enamines, or Oxazolidines Prepared from Citronellal and Amines Ritsuko Ishino* and J u Kumanotani* Engineering Research Institute, Faculty of Engineering, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo,
