A Study of the Structures of Intermediates in the Reaction of 1,3-Diketones and Hydrazines.

New Synthetic Routes to Δ2-Pyrazolin-5-ones

“…Of the several reasonable alternative mechanisms, most of which differ only in the order of occurrence of the dozen or so minor steps, the given mechanism was favored for the following reasons. (a) Stable analogs of the intermediate 14 have been isolated by other workers (10). (b) The intermediate 14 can be diverted to an alternative product, 4-hydroxy-I-methyl-3,5-diphenylpyrazole (17), if Z -is a poorer leaving group than Br-.…”

Cyclization of hydrazones of .alpha.,.beta.-unsaturated carbonyl compounds. Biscarbamyl- and bisthiocarbamylhydrazones of malondialdehyde

“…Recrystallization was carried out from saturated hot water solutions: yield 61.5%; uv max (H20) 234 nm (e 8150) at pH 6.0; *H nmr (D20, 60°), lock signal i erf-butyl alcohol ( 1.28 from TMS), 7.08 (t, 1 H, Jm-= 1.6, Js.4 = 1.2 Hz, H-3), 5.28 (qt, 1 H, /6.4 = 10.0, "< = 4.0 Hz, H-5), 3.26 midpoint, 3.24 caled (8-line pattern, 1 H, gem /4,4-= -19.5, Ji,6 = 10.0, Ji.s = 1. 2 Hz, H-4), 2.82 midpoint, 2.85 caled (8-line pattern, 1 H, gem J4-,4 = -19.5, J4-,6 = 4.0, Jv,3 = 1.6 Hz, H'-4) (relative intensities of inner and outer lines of overall 16-line pattern caled11 1:2.6); nmr (DMSO-íZ6, 10% pyridine-ds, 31.5°) 7.46 (s, 1, NH of hydrazine, H-7), 7.08 (s, unresolved triplet, 1, CH, H-3), 6.72 (s, 2, NH of amide, H-9 and H'-9), 6.32 (s, 2, NH of amide, H-ll and H'-ll), 5.50 (d, 1, NH of hydrazine, H-6), 5.33 (m, 1 , H-5), 3.28 (center of 8-line pattern, 1 , /4|4• = -18 Hz, H-4), 2.95 (center of 8-line pattern, 1 H, J4.,4 = -18 Hz, H'-4) (relative intensities of inner and outer lines of overall 16-line pattern 1:2.6); mass spectrum (70 eV) m/e (rel intensity) 112 (18), 111 (2), 86 (3), 76 (2), 75 (10), 70 (7), 69 (100), 68 (45), 67 (4), 60 (2), 59 (2), 58 (3), 55 (3), 54 (4), 52 (3), 44 (25), 43 (43), 42 (43), 41 (14), 40 (7), 39 (7), 38 (2).…”

“…Recrystallizations of the sublimate from «-heptane yielded a product, mp 68-69°. For comparative purposes, pyrazole was also prepared from hydrazine HC1 and malonaldehvde: mp 69-70°;3 uv max (H20) 210 nm (e 3520) at pH 6.0; nmr (CDC13), from TMS, 6.28 (t, 1 H, J4|3 = 2.0, J4,5 = 2.0 Hz, H-4), 7.55 (d, 2 H, /5,4 and /3,4 = 2.0 Hz, H-3 and H-5), 11.92 (s, 1 H, HN); mass spectrum m/e (rel intensity) 68 M+ (100), 69 (8), 67 (15), 42 (9), 41 (50), 40 (29), 39 (19), 38 (12), 37 (5).…”