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E X P E R I M E N T A
L
4-Ethynyl-S-aminometl~l-l,3-dimethylpyrazole (Va). A 1.7-g sample of compound (IVa) [1] was mixed
with sodium amide (from 2.3 g of sodium) in 300 ml of ammonia for 0.5 h, and 300 ml of ether was then added.
The ammonia was removed, and the excess of sodium amide and the sodium acetylide were decomposed with
water. After distillation of the ether compound (Va) was sublimed at 80-I00~C (1 mrn Hg). The yield was 1.2
g (80%); mp 76-65.5°C (from petroleum ether). Found ~: C 64.35; H 7.46; N 28. 31. CsHIINs. Calculated ~:
C 64.40; H 7.43; N 28.17. The PMR spectrum is given in Fig. 1. IR spectrum (carbontetrachloride, ~,
cm-1): 2118 (C----C), 3320 (HC-=C), 3400, 3220, 1618 (NH2 associated ).
Similarily from compound ([Vb) [I] we obtained 4-ethynyl-5-aminomethyl-l-methylpyrazole (Vb). The
yield was 80.8%; mp 47-47.5°C (from petroleum ether). Found %: N 32.04. CTHDNs. Calculated ~: N 31.09.
PMR spectrum (CDCIs, 5, ppm): 3.05 (HC=C); 1.42 (NH2); 3.88 (5-CH2N/); 7.47 (Z-H); 3.82 (NCHs). IR
spectrum (carbontstrachloride, ~, cm-1): 2124 (C='C), 3325 (H--C = C), 3407 (NH2).
Reaction of Phenylchloroacetylene (1) with Sodium Amide. The reaction of 10 g of compound (1) with
sodium amlde (from 13.3 g of sodium) was carried out as described for compound (IVa). By distillation we
isolated 4.3 g (57.5~) of compound (If) ~p 65°C/30 mm HE, nD2° 1.5480 [11]) and 1.4 g (16.3%) of compound (HI)
(bp 75°C/2 mm Hg) [11]. PMR spectrum (carbontetrachloride, 5, ppm): 3.57 (CH2); 7.20 (Cells). IR spec-
trum (carbontetrachloride, ~, cm-1): 2260 (C~ N), 3043, 3077, 3100 (C--H of r i n g ) .
A 1.3-g sample of compound (HI) was boiled with 20 ml of concentrated hydrochloric acid for 1.5 h; the
yield of phenylacetic acid was 0.8 g (53%); mp 76~C (from water). A mixed melting t e s t with an authentic
sample did not give a melting point depression.
.4-Bromosthynyl-l~3,5-trimethylpyrazole (VIIa). To a solution of KOBr, prepared from 7.8 g of Br2and
20 g of potassium hydroxide in 75 ml of water, at 10°C we added 4.7 g of compound (VI) [12] in 20 ml of di-
oxane. The mixture was stirred at 20°C for 3 h, and compound (VIIa) was extracted with chloroform. After
recrystallizatlon from a 20 : 1 mixture of petroleum ether and benzene the yield of compound (VIIa) was 5.5 g
(73.7~); mp 136-137°C. Found %: Br 37.60. CsHsBrN2. Calculated r~: Br 37.50. PMR spectrum (carbon
tetrachloride, 5, ppm): 3.65 (NCRs); 2.17 and 2.25 (3-and 5-CH3). IR spectrum (carbon tetrachloride, v,
cm-1): 2208 (C=" C).
4-Iodoethynyl-l,3,5-trlmsthyl~azole
droxide at 5°C, while stirring, we added 1.3 g of compound (VI) and then 7.8 g of iodine. The product was
then treated as described for (VIIa). 2.5-g sample of the crude compound (VIIb) was recrystaIlized from a
3:1 mixture of benzene and petroleum ether. The yield was 1.9 g (74.5%); m p 178-179°C (decomp.). Found
~: C 37.08; H 3.62; I 48.85. CsHgIN2. Calculated %: 36.94; H 3.49; I 48.80. PlMR spectrum (chloro-
(VIIb). T o 55 ml of a 12.5~ aqueous soIutlon of potassium hy-
A
C
form, 5, ppm): 3.73 (NCH~); 2.28 and 2.31 (3- and 5-CH3). IR spectrum (carbontetraohlorlde, ~, cm-1):
2180 (C =" C).
Reaction of 4-Bromoethynyl-1 r3,5-trimethylpyrazole (VIIa) with Sodium Amide. A 2.1-g sample of
compound (VIIa) in 100 ml of ether was added to sodiumamide (from2 g of sodium) in 150 ml of ammonia, and
the rn!~ure was stirred for 3 h. After the usual treatment 1.1 g (83.3%) of compound (VI) was isolated by
vacuum sublimation. The uneublimed residue (0.1 g) probably contains 1,3,5-trimethyl-4-pyrazoiylacetoni-
trile (~C=" N 2233 cm-1).
Under analogous c0nditio~ 0.5 g (88.2%) of compound (VI) was obtained from 1.1 g of compound (VIIb).
C
O N C L U S I O N S
i. The action of sodium a m l d e in a m m o n i a on 4-chloroethynyl-N-alkylpyrazoles
having a methyl group
at position 5 leads to the formation of rearranged substitution products, i.e., the respective 5-(aminomethyl)-
~frazolylaoetylenes. A suggestion is made about the mechanism of the reaction.
2. Under the same conditions 4-bromo- or
4-iodoethynyl-5-methylpyrazoles,
like phenylchloroacetylene,
exchange the halogen atom for sodium. At the same time a s m a l l amount of the a r y l - or heteroarylacetoni-
trile is formed.
L I T E R A T U R E C I T E D
1.
S. F. Vasilevskii, A. N. Sinyaknov, M. S. Shvartsberg, ar~ I. L. Kotlyarevsldi, Izv. Akad. Nauk
SSSR, Ser. Khlm., 2288 (1976).
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