Cholinesterase Reactivators
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2-[(Hydroxyimino)methyl]pyridine-4-carboxamide (2)
A suspension of ester 1a (1.12 g, 6.15 mmol) in 25% aqueous ammonia (5.6 ml) was stirred at room
temperature for 24 h. The product was filtered off (0.89 g, 93%) and crystallized from 50% aqueous
ethanol; m.p. 241–243 °C. For C7H7N3O2 (165.2) calculated: 50.91% C, 4.27% H, 25.44% N; found:
50.62% C, 4.33% H, 25.28% N. 1H NMR spectrum: 11.31 s, 1 H (OH); 8.67 dd, 1 H, J = 0.6 and
5.0 (H-6); 8.16 s, 1 H + 8.13 dd, J = 0.6 and 1.6, 1 H (H-3, CH aldoxime); 7.70 dd, 1 H, J = 1.6
and 5.0 (H-5); 7.58 bs, 2 H (NH2).
2-[(Hydroxyimino)methyl]-4-methoxycarbonyl-1-methylpyridinium Iodide (3a)
A solution of oxime 1a (0.5 g, 3.3 mmol) and methyl iodide (1.5 g, 12 mmol) in dimethylformamide
(5 ml) was heated in an ampoule at 60 °C for 12 h. Then the reaction mixture was evaporated in
vacuum, and the residue was double crystallized from ethanol. Yield 0.63 (70%) of a yellow sub-
stance, m.p. 212–214 °C (dec.). For C9H11IN2O3 (322.1) calculated: 33.56% C, 3.44% H, 8.70% N,
1
39.40% I; found: 33.83% C, 3.24% H, 8.55% N, 39.11% I. H NMR spectrum: 9.18 d, 1 H, J = 6.5
(H-6); 8.73 s, 1 H (CH aldoxime); 8.64 d, 1 H, J = 1.9 (H-3); 8.36 dd, 1 H, J = 1.9 and 6.5 (H-5);
4.48 s, 3 H (NCH3); 4.02 s, 3 H (OCH3).
2-[(Hydroxyimino)methyl]-4-ethoxycarbonyl-1-methylpyridinium Iodide (3b)
The compound was prepared analogously to 3a; yield 70%. Crystallization from ethanol gave a yellow
substance, m.p. 191.5–194 °C (dec.). For C10H13IN2O3 (336.1) calculated: 35.73% C, 3.90% H,
8.33% N, 37.75% I; found: 35.35% C, 4.19% H, 8.11% N, 37.43% I. 1H NMR spectrum: 13.18 bs,
1 H (OH); 9.21 d, 1 H, J = 6.3 (H-6); 8.76 s, 1 H (CH aldoxime); 8.65 d, 1 H, J = 2.2 (H-3); 8.41 dd,
1 H, J = 2.2 and 6.3 (H-5); 4.49 s, 3 H (NCH3); 4.48 q, 2 H, and 1.40 t, 3 H, J = 7.2 (CH2CH3).
4-Carbamoyl-2-[(hydroxyimino)methyl]-1-methylpyridinium Iodide (3c)
The compound was prepared analogously to 3a; yield 65%. Crystallization from ethanol gave a yel-
low substance, m.p. 214–219 °C (dec.). For C8H10IN3O2 (307.1) calculated: 31.29% C, 3.28% H,
13.68% N, 41.32% I; found: 30.96% C, 3.35% H, 13.52% N, 41.08% I. 1H NMR spectrum: 12.85 bs, 1 H
(OH); 9.13 d, 1 H, J = 6.5 (H-6); 8.69 s, 1 H (CH aldoxime); 8.63 d, 1 H, J = 1.9 (H-3); 8.32 dd, 1 H,
J = 1.9 and 6.5 (H-5); 8.11 bs, 2 H (NH2); 4.41 s, 3 H (CH3).
1-(4-Bromobut-2-enyl)-2-[(hydroxyimino)methyl]pyridinium Bromide (4)
A mixture of pyridine-2-carbaldoxime (12.2 g, 0.1 mol) and 1,4-dibromobut-2-ene (42.5 g, 0.2 mol)
in acetone (400 ml) was allowed to stand at room temperature for 6 days. The product separated as
a grey substance (11.5 g, 34%), m.p. 121–127 °C (dec.).
4-Carbamoyl-2′-[(hydroxyimino)methyl]-1,1′-(but-2-ene-1,4-diyl)bispyridinium Dibromide (5a)
A solution of crude monoquaternary salt 4 (11.5 g, 0.034 mol) and isonicotinamide (5 g, 0.041 mol)
in dimethylformamide (100 ml) was allowed to stand for 2 days to obtain 13.44 g of the crude pro-
duct, m.p. 190–199 °C (dec.). This was crystallized from ethanol (160 ml) and water (20 ml) to obtain
12.85 g (81%) of the hemihydrate, m.p. 117–123 °C. For C16H18Br2N4O2 0.5 H2O (467.2) calcu-
lated: 41.14% C, 4.10% H, 11.99% N, 34.21% Br; found: 40.98% C, 4.26% H, 12.13% N, 34.01% Br.
1H NMR spectrum: 13.09 s, 1 H (OH); 9.29 d, 2 H, J = 6.6 (H-2′, H-6′); 9.21 d, 1 H, J = 6.0 (H-6); 8.79 bs,
1 H + 8.31 bs, 1 H (NH2); 8.71 s, 1 H (CH aldoxime); 8.66 t, 1 H, J = 8.5 (H-4); 8.51 d, 2 H, J =
Collect. Czech. Chem. Commun. (Vol. 63) (1998)