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Pyridine Pyrimidine and Pyrazine Derivatives with an Isocyanato Substituent Vicinal to Nitrogen.

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spectrum of ( 5 ) which differs from that given previously[6!
This leads to the sequence n, x, n, K, ... for the four uppermost occupied molecular orbitals (arranged in order of
decreasing energy) and not to n, n, x, x,_._
as originally
presumed. In this case, unlike that of ( 4 ) , the order of the
orbitals referring to the irreducible representations B,, and
B,, is reversed.
4. In the photoelectron spectrum of i,4-cyclohexanedione
(6) the splitting A(n) cannot be determined unambiguously.
The band assigned to the ionization of the “lone” electron
i
- HO-Q
O
W
0
(7)
pairs is somewhat broadened and its shape near the maximum is indicative of a splitting of A(n)=O.l, eV. Such a
small value suggests that the twist conformation (7)
(symmetry O2)I7]is the preferred one.
Received: March 11,1971 [Z 390 IE]
German version : Angew. Chem. 83,405 (1971)
[I] Part 24 ofApplications of Photoelectron Spectroscopy. This work
is part of Project No. SR 2.120.69 of the Schweizerischer Nationalfond.
-Part 23: P . Bischof; E. Heilbronner, H . Prinzbach, and H . D. Murtin,
Helv. Chim. Acta, in press.
[2] J . R. Swenson and R . Hofmunn, Helv. Chim. Acta 53,2331 (1970).
[3] R. Hofmann, Accounts Chem. Res. 4, I (1971); R . Hofmann, E.
Heilbronner, and R. Gleiter, J. Amer. Chem. SOC.92, 706 (1970).
[4] ‘I: Koapmans, Physica 1, 104 (1933); W G. Richards, J. Mass Spectrom. Ion Physics 2,419 (1969).
[S] L. Salem and J . S. W i g h t , J. Chem. SOC. D 1969, 1370; J. Amer.
Chem. SOC.91, 5947 (1969); L. Salem, Chem. Brit. 5, 449 (1969); P .
Bischof, E. Haselbach, and E . Heilbronner, Angew. Chem. internat. Edit.
9,953 (1970); R. H o f m n n and R . B. Dauidson, private communication.
[6] D. W IIuner, C . Baker, A . D. Baker, and C . R. Brundle: Molecular
Photoelectron Spectroscopy. Wiley-Interscience. London 1970.
[7] P . Dowd, Th. Dyke, and W Klemperer, J. Amer. Chem. SOC.92,
6327 (1970).
[8] Tables of Interatomic Distances and Configuration in Molecules
and Ions. Special Publication No. 11, The Chemical Society, London
1958.
The isocyanato derivatives ( 4 ) to (10) have been prepared
for the first time in this way.
NCO
(4)
(5)
co
R
(6), R = C1
(7), R
(8), R
( 9 1 9
(10)
= CC13
= C2C1,
R = C6H5
They are distillable colorless liquids or solids of high
reactivity (Table 1).In their I
R spectra the NCO band lies
at 2250 cm-’.
Table 1. Properties of the isocyanato derivatives (4) to (10).
Pyridine, Pyrimidine, and Pyrazine Derivatives
with an Isocyanato Substituent Vicinal to Nitrogen
By Ulrich von Gizycki“]
No derivative of pyridine, pyrimidine, or pyrazine has
previously been isolated in which an isocyanato group
occurs in the vicinal position to nitrogen. 2-Isocyanatopyridine could be obtained only as dimer“’; and 2-isocyanato-3-methylpyridine(2) is stable only in its dimeric
form (3), m. p. 212-215°C. This dimer (3) is obtained in
quantitative yield by reaction of 3-methyl-2-pyridinamine
with diphenyl carbonate via the intermediates ( I ) and (2).
We have found that electronegative substituents hinder
this dimerization, so that 2-pyridinamines substituted in
this way can be converted into the monomeric isocyanato
derivatives. This reaction occurs very smoothly when the
aminoheterocycle is treated with oxalyl chloride. It can
be applied also to pyrimidinamines and pyrazinamines.
[‘I
Dr. U. v. Gizycki
Wissenschaftliches Hauptlaboratorium,
Farbenfabriken Bayer AG
5 0 9 Leverkusen (Germany)
402
(4)
(5)
(6)
(7)
(8)
(9)
(10)
B. p. (Tjtorr)
At room temp.
Yield (%)
101-102/0.06
9&91/0.06
81-82/0.1
115-1 17/0.1
143-144/0.08
147-148/0.1
100/0.07
Solid
Solid
Liquid
Liquid
Solid
Solid
Solid
85
90
90
75
72
95
70
The corresponding urethanes (Table 2) are obtained
smoothly by reaction with alcohols.
Table 2. Melting points of the urethanes prepared from the isocyanate
derivatives ( 4 ) to (10).
Isocyanate
Alcohol
M. p. (“C)
Ethanol
Cyclohexanol
I-Butanol
1,3-D1chloro-2-propanol
1,3-Dichlor0-2-propanol
1,3-Dichloro-2-propanol
Ally1 alcohol
131-132
144145
106-108
88-90
97-98
16162
80
Angew. Chem. internat. Edit.
Vol. 10 (1971) 1 No. 6
Experimental:
The a-aminoheterocycle (0.1 mol) is dissolved in anhydrous benzene or toluene and dropped into a boiling mixture
of oxalyl chloride (0.4-0.5 mol) and anhydrous benzene or
toluene (1-2 mol). The whole is boiled under reflux until
evolution of gas is completed ( 2 4 h). After filtration
(crystalline precipitates that are sometimes formed consist of the bisoxamides) and removal of solvent by distillation, the residue is distilled in a vacuum.
formation of the tritylated s-triazinamines, e.g., (7), m. p.
191-193°C.
c1
(7)
Received: March 11,1971 [ Z 391a IE]
German version: Angew. Chem. 83,406 (1971)
[l] U . 0. Gizycki and G . Oertel, Angew. Chem. 80, 363 (1968); Angew
Chem. internat. Edit. 7, 381 (1968).
Isocyanato-s-triazines
By Ulrich von Gizycki"'
Only one isocyanato-s-triazine, namely the 2,4-dichloro-6isocyanato derivative ( I ) , has previously been isolated,
and that from tetrameric cyanogen chloride by a route that
cannot be generalized"].
We have found that mono- and di-isocyanato derivatives
ofs-triazinecan be readily prepared in good yield by reaction
of the appropriate s-triazinamine with oxalyl chloride.
Experimental:
Finely powdered s-triazinamine (0.1 mol) is suspended in a
mixture of oxalyl chloride (0.3-0.5 mol per amino group)
and anhydrous toluene or chlorobenzene (1-2 mol) [but
distilled thiophane dioxide for ( 2 ) ] , and the mixture is
boiled under reflux until evolution of gas is complete
(7-8 h). After filtration and removal of solvent by distillation, the residue is distilled in a vacuum.
Received: March 11, 1971 [Z 391b IE]
German version: Angew. Chem. 83,407(1971)
[I] X Kodoma and 'Z Sekiba, J. SOC.Org. Syn. Chem., Japan 21, 888
(1963).
Isocyanatoquinones
By Ulrich von Gizycki'']
Quinones carrying an isocyanato substituent in the quinonoid ring have so far been unknown. We now report syntheses of two representatives of this new class of compound.
The isocyanato derivatives (1)-(6) are colorless solids or
liquids that distil without decomposition and are highly
reactive (Table 1). In their IR spectrum the NCO band lies
at 2250 cm- '. The reaction proceeds better the more
electronegative is the substituent R.
When a mixture of finely powdered 2,5-diamino-3,6-dichIoro-l,4-benzoquinone (100g), oxalyl chloride (400g),
anhydrous butyl acetate (200 ml), and anhydrous chlorobenzene (550 ml) is boiled under reflux until gas evolution
ceases (-36 h), then, on cooling, red needles of 2,5-dichloro-3,6-diisocyanato-1,4-benzoquinone
( I ) (about 50 g)
separate.
Table 1. Properties of the isocyanates ( I ) to (6)
Isocyanate
B. p. (T i t o r r )
At room temp.
Yield (%)
(1)
105-106/1&12
147.51760
13413510 2-0.3
84-8510.2
126-12710.9
152-15310.3
Solid
Liquid
Solid
Solid
Liquid
Solid
93
70
70
85
84
75
(2)
(3)
14)
(5)
(6 1
Table 2. Melting points of the urethanes prepared from the isocyanates
(1) to (6).
Isocyanate
Alcohol
M. p. ("C)
(1)
1,3-Dichloro-2-propanol
Phenol
1-Butanol
Phenol
1,3-Dichloro-2-propanol
Phenol
124-125
136-137
105-108
161-163
11&114 [a]
Dec. from 21 5
(2)
(3)
(4)
(5)
(6)
M. p. of ( I ) : 259-260°C. IR: NCO band at 2205 cm- ',
CO at 1665 and 1675 cm- '. Bis(ethy1urethane): orange
needles, m. p. 220-221 "C.
(2) was
Yellow 2-chloro-3-isocyanato-1,4-naphthoquinone
obtained analogously in 75% yield from 2-amino-3-chloro1,4-naphthoquinone (50 g) and oxalyl chloride (200 g) in
anhydrous o-dichlorobenzene.
"
[a] Contains solvent (CCI,).
The isocyanates ( I ) to (6) react smoothly with alcohols
or phenols, yielding urethanes or diurethanes (Table 2).
Reaction with triphenylmethanol at 0-20°C affords the
urethanes which at higher temperatures lose CO, with
[*] Dr. U. v. Gizycki
Wissenschaftliches Hauptlaboratorium,
Farbenfabriken Bayer AG
509 Leverkusen (Germany)
Angew. Chem. internat. Edit. 1 Vol. 10 (19711
(1)
0
(2)
The isocyanate (2) crystallizes after filtration and concentration of the solution to one-third of its volume.
',
M. p. of (2) : 140- 142"C. IR : NCO band at 2200 cmCO at 1670cm-'. Ethylurethane: yellow needles, m. p.
135-136"C.
Received: March 11,1971 [Z 391c IE]
German version: Angew. Chem. 83, 408(1971)
1 No. 6
403
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pyridin, isocyanates, pyrazines, nitrogen, substituents, vicinal, derivatives, pyrimidine
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