128
A.G. Makarov et al. / Journal of Fluorine Chemistry 165 (2014) 123–131
N
Free 16 was obtained by treatment of 16Á2HCl with aqueous
Na2CO3 followed by extraction with Et2O. The filtrate was
neutralized with 5.27 g of Na2CO3 and extracted with Et2O
(20 Â 15 ml). Combined ether extract was dried over MgSO4,
evaporated to dryness and the residue was sublimed at 90 8C/
1 mm. Compound 16 was obtained in the form of colorless
crystals.
SeO2
SeCl4
R
R
F
Se
Se
N
NH2
NH2
26-28
R
F
N
N
F
13, 14, 17
(d) (modified procedure [7b]) A mixture of 227 mg (0.0008 mol) of
24, 503 mg (0.008 mol) of Zn dust, 1.5 ml (0.018 mol) of
hydrochloric acid and 2.7 ml of ethanol was refluxed for 4 h.
After cooling to 20 8C, 15 ml of water was added, the precipitate
of was filtered off. The filtrate was evaporated to dryness and
the residue sublimed at 120 8C/1 mm. Combined product was
crystallized from ethanol. Compound 17 was obtained in the
form of white crystals.
26
Scheme 5. Synthesis of compounds 26–28.
(b) A solution of 1.36 g (4.1 mmol) of 36 in 30 ml of MeCN was
added dropwise during 2 h to refluxed and stirred suspension
of 0.71 g (4.7 mmol) of freshly calcinated CsF in 200 ml of
MeCN. After additional 0.5 h, the reaction mixture was cooled
to 20 8C and filtered. The solvent was distilled off under
reduced pressure and the residue was extracted with hexane
(5 Â 10 ml), the extract was evaporated and the residue
sublimed in vacuo (110 8C/1 mm). Compound 22 was obtained
4.3.5. Quinoxalines 1–8
in the form of light-yellow crystals. UV–vis,
216 (4.15, sh.), 232 (4.25), 304 (4.07), 311 (4.05), 317 (3.14),
344 (3.49, sh.). FL, lmax exc), nm: 406 (316).
lmax, nm, (log e):
(a) A mixture of 250 mg (1.4 mmol) of 10, 116 mg (1.7 mol) of
crystalline glyoxal (a), or 241 mg (1.7 mol) of 40% aqueous
glyoxal (b), and 6 ml of ethanol was refluxed for 4 h. The
solvent was distilled off at reduced pressure, and the residue
was sublimed at 50 8C/1 mm and crystallized from hexane.
Compound 1 [4a] was obtained in the form of colorless crystals
(
l
4.3.4. 1,2-Diaminoarenes 12–14, 16 and 17
suitable to XRD. UV–vis (EtOH),
lmax, nm, (log e): 236 (4.49),
311 (3.58). FL, lmax exc), nm: 410 (310).
(
l
(a) A mixture of 285 mg (ꢀ0.002 mol) of 20, 275 mg (ꢀ0.006 mol)
of NaBH4, 78 mg (0.0003 mol) of Co(OAc)2Á4H2O and 5 ml of
ethanol was refluxed for 9 h. After cooling to 20 8C, the reaction
mixture was diluted with water, and precipitate was filtered off
and washed with ether. The filtrate was extracted with ether
(4 Â 25 ml). The combined ether solution was dried over
MgSO4 and evaporated. Concentrated HCl (0.1 ml) was added
to the residue, and the mixture was extracted with toluene
(3 Â 7 ml). Aqueous solution was neutralized with 353 mg of
Na2CO3, evaporated to dryness and the residue sublimed at
75 8C/1 mm. Compound 12 was obtained in the form of
colorless crystals.
(b) A mixture of 3.5 mmol of 11 or 12 and 514 mg (3.5 mmol) of
40% aqueous glyoxal in 15 ml of ethanol was refluxed for 5 h,
the solvent was distilled off under reduced pressure, and the
residue sublimed at 80 8C/1 mm.
Compound 2 was obtained in the form of white crystals.
Single crystals suitable to XRD were obtained by crystallization
from ethanol. UV–vis,
FL, lmax exc), nm: 388 (310).
Compound 3 was obtained in the form of white crystals.
UV–vis, max, nm, (log ): 234 (4.46), 313 (3.60). FL, lmax exc),
nm: 409 (310).
lmax, nm, (log e): 239 (4.57), 310 (3.42).
(
l
l
e
(l
(c) A solution of 380 mg (2.6 mmol) of 40% aqueous glyoxal in
10 ml of ethanol was added during 2 h to refluxed solution of
2.6 mmol of 13, or 14, or 15 in 10 ml of the same solvent. The
reaction mixture was refluxed for 3 h, the solvent was distilled
off under reduced pressure, and the residue sublimed at 70 8C/
1 mm and crystallized from hexane.
(b) Compounds 13 and 14 were prepared by reduction of 21 and 22
by SnCl2/HCl under conditions [35] similar to described above
(item 4.3.1), and purified by sublimation in vacuo and
crystallized from hexane. Compounds 13 and 14 were obtained
in the form of colorless crystals.
(c) A mixture of 840 mg (ꢀ4 mmol) of 39 [36], 3.05 g (ꢀ14 mmol)
of SnCl2Á2H2O and of 4 ml (ꢀ50 mmol) of concentrated HCl was
refluxed for 0.5 h. After cooling to room temperature, crystals
of 16Á2HCl (0.133 g) were filtered off being suitable to XRD.
Compound 4 was obtained in form of yellowish crystals.
UV–vis,
nm: 382 (318).
l
max, nm, (log
e
): 242 (4.67), 318 (3.57). FL, lmax (lexc),
´
˚
Fig. 5. XRD molecular structure (displacement ellipsoids at 30%) of 26 (Cl atoms are 0.60: 0.40(1) disordered over two positions) and 28. Selected bond lengths (A) and bond
angles (8): 26: Se2–N1 1.791(6), Se2–N3 1.798(6), N1–C7a 1.327(9), N3–C3a 1.323(9), C3a–C7a 1.440(10); N1–Se2–N3 93.4(3), Se2–N1–C7a 107.2(4), Se2–N3–C3a 106.8(5),
N1–C7a–C3a 116.0(6), N3–C3a–C7a 116.5(6). 28: Se2–N1 1.788(6), Se2–N3 1.803(7), N1–C9b 1.322(9), N3–C3a 1.311(11), C3a–C9b 1.431(11); N1–Se2–N3 92.9(3), Se2–N1–
C9b 107.1(5), Se2–N3–C3a 107.1(5), N3–C3a–C9b 116.4(7), N1–C9b–C3a 116.4(7).