2
Journal of Chemistry
2.2.1. N,N-Diethylimidodicarbonimidic Diamide (1). Yield
NH
NH
NH
NH
37%. White crystals obtained from ethanol. Mp 190∘C (Dec).
.(2
1H NMR (400 MHz, DMSO-ꢆ6) ꢃ: 1.16 (t, 6H, CH × 2),
N
H
N
H
.(2
N
H
N
3
2.89 (q, 4H, N-CH × 2), 6.60 (bs, 5H, -NH × 5) ppm. 13C
2
Phenformin
Metformin
NMR (100 MHz, DMSO-d6) ꢃ: 11.1 (-CH ), 41.4 (CH ), 162.9
3
2
(C=NH) ppm. MS/EI: m/z (% int. rel). 157 (M+, 25%), 85
Figure 1: Biguanides that activate AMPK.
(100%). Anal. Calcd for C H N : C, 45.84; H, 9.62; N, 44.55.
6
15
5
Found: C, 45.80; H, 9.58; N, 44.57.
2.2.2. N-[Amino(imino)methyl]pyrrolidine-1-carboximidam-
ide (2). Yield 46%. White crystals obtained from ethanol. Mp
156.4–158.7∘C. 1H NMR (400 MHz, DMSO-ꢆ6) ꢃ: 1.82 (q, 4H,
CH -CH ), 3.07 (t, 4H, N-CH × 2), 6.60 (bs, 5H, -NH × 5)
number of metabolic diseases such as type 2 diabetes mellitus
Another biguanide, phenformin (Figure 1), also activates
AMPK, but in 1978 it was retired from the market due to its
toxicity, producing lactic acidosis as a major side effect that
prompted the withdrawal of phenformin as a treatment for
In our ongoing research on molecules with antidiabetic
activity [6, 7], we report in this manuscript the preparation of
ten alicyclic and aromatic biguanides (Table 1), as well as the
in vitro activation of AMPK. We also describe the molecular
docking of the most active compounds in the nucleotide
binding site on ꢀ-subunit of AMPK, and their in vivo anti-
hyperglycemic effect using a streptozotocin–nicotinamide rat
model of noninsulin dependent diabetes mellitus.
2
2
2
ppm. 13C NMR (100 MHz, DMSO-d6) ꢃ: 23.7 (CH -CH ),
2
2
44.7 (CH -N), 162.9 (C=NH) ppm. MS/EI: m/z (% int. rel).
2
155 (M+, 2%), 85 (100%). Anal. Calcd for C H N : C, 46.43;
6
13
5
H, 8.44; N, 45.12. Found: C, 46.50; H, 8.48; N, 45.01.
2.2.3. N-[Amino(imino)methyl]piperidine-1-carboximidamide
(3). Yield 63%. White crystals obtained from ethanol. Mp
116.5–118.0∘C. 1H NMR (400 MHz, DMSO-ꢆ6) ꢃ: 1.03 (m, 4H,
CH -CH ), 1.05 (m, 2H, CH ) 3.40 (t, 4H, N-CH × 2), 6.58
2
2
2
2
(bs, 5H, -NH × 5) ppm. 13C NMR (100 MHz, DMSO-d6) ꢃ:
18.5 (CH -CH ), 30.6 (CH ), 56.1 (CH -N), 162.9 (C=NH)
2
2
2
2
ppm. MS/EI: m/z (% int. rel). 169 (M+, 40%), 85 (100%). Anal.
Calcd for C H N : C, 49.68; H, 8.93; N, 41.38. Found: C,
7
15
5
2. Materials and Methods
49.62; H, 8.90; N, 41.40.
2.1. Chemicals and Analytical Methods. Starting materials
and solvents were purchased from Sigma-Aldrich and were
used without any further purification. Melting points were
determined using an EZ-Melt MPA120 automated melting
point apparatus from Stanford Research Systems and are
uncorrected. Reactions were monitored by thin layer chro-
2.2.4. N-[Amino(imino)methyl]morpholine-4-carboximidam-
ide (4). Yield 22%. White crystals obtained from ethanol. Mp
178.4–180.5∘C. 1H NMR (400 MHz, DMSO-d6) ꢃ: 3.06 (t, 4H,
CH -O-CH ), 3.75 (t, 4H, N-CH × 2), 6.61 (bs, 5H, NH ×
2
2
2
5) ppm. 13C NMR (100 MHz, DMSO-d6) ꢃ: 43.2 (CH -N),
2
63.7 (CH -O), 162.3 (C=NH) ppm. MS/EI: m/z (% int. rel). 171
2
matography on 0.2 mm precoated silica gel 60 F Merck
254
(M+, 15%), 85 (100%). Anal. Calcd for C H N O: C, 42.09;
1
6
13
5
plates. H NMR spectra were recorded on Varian Oxford
H, 7.68; N, 40.91. Found: C, 42.10; H, 7.65; N, 40.88.
(400 MHz) and 13C NMR (100 MHz), as well as H NMR
1
(200 MHz) and 13C NMR (50 MHz) instruments. Chemical
2.2.5. N-[Amino(imino)methyl]-4-methylpiperazine-1-carbox-
shifs are given in ppm relative to tetramethylsilane (Me Si,
4
imidamide (5). Yield 54%. White crystals obtained from
ꢃ ꢄ =) in DMSO-d and CDCl ; ꢅ values are given in Hz.
6
3
ethanol. Mp 148∘C (Dec). H NMR (400 MHz, DMSO-ꢆ6)
1
e following abbreviations are used: s, singlet; d, doublet;
q, quartet; dd, doublet of doublet; t, triplet; m, multiplet;
bs, broad signal. MS were recorded on a JEOL JMS-700
spectrometer by electronic impact. Element analyses have
been carried out on an Elementar Vario ELIII instrument.
ꢃ: 2.48 (s, 3H, CH ), 2.73 (m, 4H, CH -N-CH ), 3.38 (m,
3
2
6
2
4H, CH -NMe-CH ), 6.71 (bs, 5H, NH × 5) ppm. 13C NMR
2
2
(100 MHz, DMSO-d6) ꢃ: 42.5 (CH -N), 43.3 (CH -N), 49.6
2
2
(CH ), 163.3 (C=NH) ppm. MS/EI: m/z (% int. rel). 184 (M+,
3
2%), 85 (100%). Anal. Calcd for C H N : C, 45.63; H, 8.75;
7
16
N, 45.61. Found: C, 45.70; H, 8.75; N, 45.58.
2.2. General Procedure for the Synthesis of Compounds 1–10.
To a solution of dicyandiamide 21 (0.5 g, 0.0060 mol) in
toluene (5 mL) was added 1.1 mol equiv of corresponding
alkylamines 11–15 or arylamines 16–20. Afer the reaction
mixture was stirred at room temperature for 15 min, a
mixture 50 : 50 of HCl diluted in water (2.5 mL) was added
dropwise. is mixture was stirred at reflux for 3 to 16 h.
Afer that, the obtained residue was neutralized with a diluted
2.2.6. N-Benzylimidodicarbonimidic Diamide (6). Yield 56%.
White crystals obtained from ethanol. Mp 184.2–186.8∘C. 1H
NMR (400 MHz, DMSO-ꢆ6) ꢃ: 3.99 (d, 2H, CH ), 7.30 (m,
2
2H, H-2, H-6), 7.39 (m, 2H, H-3, H-5), 7.50 (m, 1H, H-4), 8.60
(bs, 6H, NH × 6) ppm. 13C NMR (100 MHz, DMSO-d6) ꢃ:
42.6 (CH -N), 129.4 (C-4), 128.8 (C-2, C-6), 129.0 (C-3, C-5),
2
solution of NH OH. Solvent was removed under vacuum,
134.5 (C-1), 154.9 (C=NH), 156.1 (C=NH) ppm. MS/EI: m/z
(% int. rel). 191 (M+, 2%), 91 (100%), 85 (40%). Anal. Calcd
for C H N : C, 56.53; H, 6.85; N, 36.62. Found: C, 56.50; H,
4
and the residues were washed with water. e crude solid
products were then recrystallized from ethanol affording title
compounds (Figure 2, Table 1).
9
13
5
6.85; N, 36.61.